%0 report %@ %A Hoffman, E.E., Carpenter, J., Chen, Q.J., Kohut, J., Merrick, R., Meyer-Gutbrod, E., Nowacek, D.P., Raghukumar, K., Record, N., Oskvig, K., Wyne, S.:Nenkey, P.:Nguyen, T. %D 2024 %J US National Academies of Science; Engineering and Medicine %R doi:10.17226/27154 %T Potential Hydrodynamic Impacts of Offshore Wind Energy on Nantucket Shoals Regional Ecology: An Evaluation from Wind to Whales %U https://doi.org/10.17226/27154 %X %0 journal article %@ 2296-7745 %A Christiansen, N., Carpenter, J.R., Daewel, U., Suzuki, N., Schrum, C. %D 2023 %J Frontiers in Marine Science %P 1178330 %R doi:10.3389/fmars.2023.1178330 %T The large-scale impact of anthropogenic mixing by offshore wind turbine foundations in the shallow North Sea %U https://doi.org/10.3389/fmars.2023.1178330 %X Structure drag from offshore wind turbines and its physical impacts on the marine environment of the German Bight are investigated in this study. The flow past vertical cylinders, such as wind turbine foundations, and associated turbulent mixing has long been studied, but questions remain about anticipated regional implications of offshore wind infrastructure on physical and biogeochemical conditions. Here, we present two existing modeling approaches for simulating wind turbine foundation effects in regional ocean models and discuss the problematic use of very high resolution in hydrostatic modeling. By implementing a low-resolution structure drag parameterization in an unstructured-grid model, we demonstrate the impacts of monopile drag on hydrodynamic conditions, validated against recent in-situ measurements. Although the anthropogenic mixing is confined at wind farm sites, our simulations show that structure-induced mixing affects much larger, regional scales. The additional turbulence production emerges as the driving mechanism behind the monopile impacts, leading to changes in both the current velocities and stratification, with magnitudes of about 10%, similar in magnitude to regional annual and interannual variabilities. This study provides new insights into the hydrodynamic impact of offshore wind farms at their current development levels and emphasizes the need for further research in view of potential restructuring of the future coastal environment. %0 journal article %@ 1070-6631 %A Holand, K., Kalisch, H., Bjørnestad, M., Streßer, M., Buckley, M., Horstmann, J., Roeber, V., Carrasco-Alvarez, R., Cysewski, M., Frøysa, H.G. %D 2023 %J Physics of Fluids %N 9 %P 092105 %R doi:10.1063/5.0165053 %T Identification of wave breaking from nearshore wave-by-wave records %U https://doi.org/10.1063/5.0165053 9 %X Using data from a recent field campaign, we evaluate several breaking criteria with the goal of assessing the accuracy of these criteria in wave breaking detection. Two new criteria are also evaluated. An integral parameter is defined in terms of temporal wave trough area, and a differential parameter is defined in terms of maximum steepness of the crest front period. The criteria tested here are based solely on sea surface elevation derived from standard pressure gauge records. They identify breaking and non-breaking waves with an accuracy between 84% and 89% based on the examined field data. %0 journal article %@ 1070-6631 %A Loft, M., Kühl, N., Buckley, M.P., Carpenter, J.R., Hinze, M., Veron, F., Rung, T. %D 2023 %J Physics of Fluids %P 72108 %R doi:10.1063/5.0156963 %T Two-Phase Flow Simulations of Surface Waves in Wind-Forced Conditions %U https://doi.org/10.1063/5.0156963 %X The paper is devoted to two-phase flow simulations and investigates the ability of a diffusive interface Cahn–Hilliard volume-of-fluid model to capture the dynamics of the air–sea interface at geophysically relevant Reynolds numbers. It employs a hybrid filtered/averaging improved detached eddy simulation method to model turbulence and utilizes a continuum model to account for surface tension if the diffuse interface is under-resolved by the grid. A numerical wind-wave tank is introduced, and results obtained for two known wind-wave conditions are analyzed in comparison to experimental data at matched Reynolds numbers. The focus of the comparison is on both time-averaged and wave-coherent quantities, and includes pressure, velocity as well as modeled and resolved Reynolds stresses. In general, numerical predictions agree well with the experimental measurements and reproduce many wave-dependent flow features. Reynolds stresses near the water surface are found to be especially important in modulating the critical layer height. It is concluded that the diffusive interface approach proves to be a promising method for future studies of air–sea interface dynamics in geophysically relevant flows. %0 journal article %@ 2296-665X %A Koedel, U., Schuetze, C., Fischer, P., Bussmann, I., Sauer, P., Nixdorf, E., Kalbacher, T., Wichert, V., Rechid, D., Bouwer, L., Dietrich, P. %D 2022 %J Frontiers in Environmental Science %P 772666 %R doi:10.3389/fenvs.2021.772666 %T Challenges in the Evaluation of Observational Data Trustworthiness From a Data Producers Viewpoint (FAIR+) %U https://doi.org/10.3389/fenvs.2021.772666 %X Recent discussions in many scientific disciplines stress the necessity of “FAIR” data. FAIR data, however, does not necessarily include information on data trustworthiness, where trustworthiness comprises reliability, validity and provenience/provenance. This opens up the risk of misinterpreting scientific data, even though all criteria of “FAIR” are fulfilled. Especially applications such as secondary data processing, data blending, and joint interpretation or visualization efforts are affected. This paper intends to start a discussion in the scientific community about how to evaluate, describe, and implement trustworthiness in a standardized data evaluation approach and in its metadata description following the FAIR principles. It discusses exemplarily different assessment tools regarding soil moisture measurements, data processing and visualization and elaborates on which additional (metadata) information is required to increase the trustworthiness of data for secondary usage. Taking into account the perspectives of data collectors, providers and users, the authors identify three aspects of data trustworthiness that promote efficient data sharing: 1) trustworthiness of the measurement 2) trustworthiness of the data processing and 3) trustworthiness of the data integration and visualization. The paper should be seen as the basis for a community discussion on data trustworthiness for a scientifically correct secondary use of the data. We do not have the intention to replace existing procedures and do not claim completeness of reliable tools and approaches described. Our intention is to discuss several important aspects to assess data trustworthiness based on the data life cycle of soil moisture data as an example. %0 journal article %@ 0196-2892 %A Streßer, M., Seemann, J., Carrasco, R., Cysewski, M., Horstmann, J., Baschek, B., Deane, G. %D 2022 %J IEEE Transactions on Geoscience and Remote Sensing %P 5105514 %R doi:10.1109/TGRS.2021.3103417 %T On the Interpretation of Coherent Marine Radar Backscatter From Surf Zone Waves %U https://doi.org/10.1109/TGRS.2021.3103417 %X Observations of microwave backscatter from shoaling and breaking surface waves acquired with a shore-based, coherent-on-receive X-band marine radar are presented. The radar was located at the dune cliff of a sandy beach with two breaker bars. Waves were approximately shore-normal (inclination < 10°) during the study period. Consistent with other studies, the backscatter intensity from breaking waves is significantly increased (≈10 dB compared to nonbreaking) with Doppler velocities close to the wave phase velocity in shallow water. The strong backscatter from active breakers can cause a significant amount of signal artifacts due to the leakage of pulse energy into adjacent range cells, in particular behind the breaking crests. In the near range, the backscatter from the undisturbed surface and such pulse smearing artifacts appear as distinct peaks inside the Doppler spectra. Thus, the velocity of both sources of scatterering can be retrieved using a dedicated peak separation algorithm. In the far range (r > 500 m), the artifacts dominate the Doppler signal behind breaking wave crests. Therefore, when investigating the spatio-temporal evolution of breaking wave-induced Doppler velocities with marine radar, the analysis should be restricted to the wave crests and the well-illuminated front faces of the waves. The evolution of Doppler spectra tracked along the crest of an exemplary individual breaking wave is extracted during the steepening, active- and post-breaking stage. %0 journal article %@ 0003-0007 %A Weber, U., Attinger, S., Baschek, B., Boike, J., Borchardt, D., Brix, H., Brüggemann, N., Bussmann, I., Dietrich, P., Fischer, P., Greinert, J., Hajnsek, I., Kamjunke, N., Kerschke, D., Kiendler-Scharr, A., Körtzinger, A., Kottmeier, C., Merz, B., Merz, R., Riese, M., Schloter, M., Schmid, H., Schnitzler, J., Sachs, T., Schütze, C., Tillmann, R., Vereecken, H., Wieser, A., Teutsch, G. %D 2022 %J Bulletin of the American Meteorological Society %N 2 %P E339-E348 %R doi:10.1175/BAMS-D-20-0158.1 %T MOSES: A Novel Observation System to Monitor Dynamic Events Across Earth Compartments %U https://doi.org/10.1175/BAMS-D-20-0158.1 2 %X Several German Helmholtz Association centers have developed this research facility as a mobile and modular “system of systems” to record energy, water, greenhouse gas and nutrient cycles on the land surface, in coastal regions, in the ocean, in polar regions, and in the atmosphere – but especially the interactions between the Earth compartments. During the implementation period (2017-2021), the measuring systems were put into operation and test campaigns were performed to establish event-driven campaign routines. With MOSES’ regular operation starting in 2022, the observation system will then be ready for cross-compartment and cross-discipline research on the environmental impacts of dynamic events. %0 journal article %@ 2352-3409 %A Schütt, E., Lehmann, M., Hieronymi, M., Dare, J., Krasemann, H., Hitchcock, D., Platt, A., Amai, K., McKelvey, T. %D 2022 %J Data in Brief %P 107759 %R doi:10.1016/j.dib.2021.107759 %T Dataset of five years of in situ and satellite derived chlorophyll a concentrations and its spatiotemporal variability in the Rotorua Te Arawa Lakes, New Zealand %U https://doi.org/10.1016/j.dib.2021.107759 %X Horizontal patchiness of water quality attributes in lakes substantially influences the ability to accurately determine an average condition of a lake from traditional in situ sampling. Monitoring programmes for lake water quality often rely on water samples from one or few locations but the assumption of representativeness is seldomly tested. Satellite observations can support environmental monitoring by detecting horizontal variability of water quality attributes over entire lakes. This article is a co-submission with Lehmann et al. (2021), who present a method to create a regional calibration of a satellite chlorophyll a algorithm and a spatial analysis of an image time series to detect recurring patchiness. Our method was developed on 13 lakes in the central North Island of New Zealand and this publication makes available the data used in our analysis and the spatial fields of results. These data are immediately valuable for practitioners operating within the region of interest providing a five year archive of synoptic water quality data and spatial fields to help optimize in situ monitoring efforts. In addition, there is value to the wider scientific community as the study lakes are a useful ‘natural lab’ for the development of aquatic remote sensing methods due to the range of trophic conditions and water colour in a single satellite image scene. Together with decades of in situ water quality records, our data is therefore useful for the development and validation of widely applicable methods of water quality retrieval from satellite data. %0 journal article %@ 0094-8276 %A Carpenter, J.R., Waterman, S., Scheifele, B. %D 2022 %J Geophysical Research Letters %N 24 %P e2022GL100450 %R doi:10.1029/2022GL100450 %T Enhanced Mixing of Heat in the Arctic Ocean Halocline in Weakly Turbulent Conditions %U https://doi.org/10.1029/2022GL100450 24 %X In the low-energy mixing environment of the Arctic Ocean halocline, a unique mixing mechanism of temperature is present. It consists of the formation of small-vertical-scale (∼1 m) intrusive features, with temperature anomalies up to ∼0.1°C, that create mean-square vertical temperature gradients that are orders of magnitude greater than the background. This finescale temperature structure results in enhanced heat fluxes in conditions of extremely weak turbulence and is responsible for an irreversible mixing of heat into cold halocline waters. The rates of thermal variance dissipation and heat transport are comparable to turbulent mechanisms in the Arctic Ocean, such as internal wave-driven mixing and double diffusive convection. We propose that in conditions of low turbulence, and in the presence of lateral thermal variability, the temperature field displays a self-regulating mechanism by which it is able to enhance its finescale structure to generate enhanced mixing, thus compensating for the lack of turbulent fluxes. %0 journal article %@ 2169-8961 %A Fettweis, M., Schartau, M., Desmit, X., Lee, B., Terseleer, N., Van der Zande, D., Parmentier, K., Riethmüller, R. %D 2022 %J Journal of Geophysical Research : Biogeosciences %N 1 %P e2021JG006332 %R doi:10.1029/2021JG006332 %T Organic Matter Composition of Biomineral Flocs and Its Influence on Suspended Particulate Matter Dynamics Along a Nearshore to Offshore Transect %U https://doi.org/10.1029/2021JG006332 1 %X The seasonal variation in concentration of transparent exopolymer particles (TEPs), particulate organic carbon (POC) and particulate organic nitrogen (PON) were investigated together with floc size and the concentration of suspended particulate matter (SPM) along the cross-shore gradient, from the high turbid nearshore toward the low-turbid offshore waters in the Southern Bight of the North Sea. Our data demonstrate that biophysical flocculation cannot be explained by these heterogeneous parameters, but requires a distinction between a more reactive labile (“fresh”) and a less reactive refractory (“mineral-associated”) fraction. Based on all data, we separated the labile and mineral-associated POC, PON, and TEP using a semi-empirical model approach. The model's estimates of fresh and mineral-associated organic matter (OM) show that great parts of the POC, PON, and TEP are associated with suspended minerals, which are present in the water column throughout the year, whereas the occurrence of fresh TEP, POC, and PON is restricted to spring and summer months. In spite of a constantly high abundance of total TEP throughout the entire year, it is its fresh fraction that promotes the formation of larger and faster sinking biomineral flocs, thereby contributing to reducing the SPM concentration in the water column over spring and summer. Our results show that the different components of the SPM, such as minerals, extracellular OM and living organisms, form an integrated dynamic system with direct interactions and feedback controls. %0 journal article %@ 2469-990X %A Carpenter, J., Liang, Y., Timmermans, M., Heifetz, E. %D 2022 %J Physical Review Fluids %N 8 %P 083501 %R doi:10.1103/PhysRevFluids.7.083501 %T Physical mechanisms of the linear stabilization of convection by rotation %U https://doi.org/10.1103/PhysRevFluids.7.083501 8 %X Despite the well-known limitations of linear stability theory in describing nonlinear and turbulent flows, it has been found to accurately capture the transitions between certain nonlinear flow behavior. Specifically, the transition in heat flux scaling in rotating convective flows can be well predicted by applying a linear stability analysis to simple profiles of a convective boundary layer. This fact motivates the present study of the linear mechanisms involved in the stability properties of simple convective setups subject to rotation. We look at an idealized two-layer setup and gradually add complexity by including rotation, a bounded domain, and viscosity. The two-layer setup has the advantage of allowing for the use of wave interaction theory, traditionally applied to understand stratified and homogeneous shear flow instabilities, in order to quantify the various physical mechanisms leading to the growth of convective instabilities. We quantitatively show that the physical mechanisms involved in the stabilization of convection by rotation take two different forms acting within the stratified interfacial region, and in the homogeneous mixed layers. The latter of these we associate with the tendency of a rotating flow to develop Taylor columns (TCs). This TC mechanism can lead to both a stabilization or destabilization of the instability and varies depending on the parameters of the problem. A simple criterion is found for classifying the influence of these physical mechanisms. %0 journal article %@ 2169-9275 %A Becherer, J., Burchard, H., Carpenter, J., Graewe, U., Merckelbach, L. %D 2022 %J Journal of Geophysical Research : Oceans %N 8 %P e2022JC018561 %R doi:10.1029/2022JC018561 %T The Role of Turbulence in Fueling the Subsurface Chlorophyll Maximum in Tidally Dominated Shelf Seas %U https://doi.org/10.1029/2022JC018561 8 %X Glider observations show a subsurface chlorophyll maximum (SCM) at the base of the seasonal pycnocline in the North Sea during stable summer conditions. A colocated peak in the dissipation rate of turbulent kinetic energy suggests the presence of active turbulence that potentially generates a nutrient flux to fuel the SCM. A one-dimensional turbulence closure model is used to investigate the dynamics behind this local maximum in turbulent dissipation at the base of the pycnocline (PCB) as well as its associated nutrient fluxes. Based on a number of increasingly idealized forcing setups of the model, we are able to draw the following conclusions: (a) only turbulence generated inside the stratified PCB is able to entrain a tracer (e.g., nutrients) from the bottom mixed layer into the SCM region; (b) surface wind forcing only plays a secondary role during stable summer conditions; (c) interfacial shear from the tide accounts for the majority of turbulence production at the PCB; (d) in stable summer conditions, the strength of the turbulent diapycnal fluxes at the PCB is set by the strength of the anticyclonic component of the tidal currents. %0 journal article %@ 2169-9275 %A Streßer, M., Horstmann, J., Baschek, B. %D 2022 %J Journal of Geophysical Research : Oceans %N 8 %P e2022JC018437 %R doi:10.1029/2022JC018437 %T Surface Wave and Roller Dissipation Observed With Shore-Based Doppler Marine Radar %U https://doi.org/10.1029/2022JC018437 8 %X Surface wave energy and dissipation are observed across the surf zone. Utilizing the concept of surface rollers, a new scaling is introduced to obtain the energy flux and dissipation related to rollers from Doppler velocities measured by a shore-based X-band marine radar. The dissipation of wave energy and hence the transformation of the incoming wave height (or energy) is derived using the coupled wave and roller energy balance equations. Results are compared to in-situ wave measurements obtained from a wave rider buoy and two bottom mounted pressure wave gauges. A good performance in reproducing the significant wave height is found yielding an overall root-mean-square error of 0.22 m and a bias of −0.12 m. This is comparable to the skill of numerical wave models. In contrast to wave models, however, the radar observations of the wave and roller energy flux and dissipation neither require knowledge of the bathymetry nor the incident wave height. Along a 1.5 km long cross-shore transect on a double-barred, sandy beach in the southern North Sea, the highest dissipation rates are observed at the inner bar over a relatively short distance of less than 100 m. During the peak of a medium-severe storm event with significant wave heights over 3 m, about 50% of the incident wave energy flux is dissipated at the outer bar. %0 journal article %@ 0022-1120 %A Carpenter, J., Buckley, M., Veron, F. %D 2022 %J Journal of Fluid Mechanics %P A26 %R doi:10.1017/jfm.2022.714 %T Evidence of the critical layer mechanism in growing wind waves %U https://doi.org/10.1017/jfm.2022.714 %X Highly resolved laboratory measurements of the airflow over wind-generated waves are examined using a novel wave growth diagnostic that quantifies the presence of Miles’ critical layer mechanism of wind-wave growth. The wave growth diagnostic is formulated based on a linear stability analysis, and results in growth rates that agree well with those found by a pressure reconstruction method as well as other, less direct, methods. This finding, combined with a close agreement between the airflow measurements and the predictions of linear stability (critical layer) theory, demonstrate that the Miles’ critical layer mechanism can cause significant wave growth in young (wave age c/u∗=6.3, where c is the wave phase speed, and u∗ the friction velocity) wind-forced waves. %0 conference lecture %@ %A Navarro Ariza, W., Streßer, M., Carrasco, R., Seemann, J., Horstmann, J. %D 2022 %J IGARSS 2022 - 2022 IEEE International Geoscience and Remote Sensing Symposium %T A Calibration-Free Methodology to Estimate Significant Wave Height Using Time-Sequences of X-Band Marine Radar Images %U %X %0 conference paper %@ 2153-7003 %A Navarro, W., Streßer, M., Carrasco, R., Seemann, J., Horstmann, J. %D 2022 %J IGARSS 2022 - 2022 IEEE International Geoscience and Remote Sensing Symposium %P 6907-6910 %R doi:10.1109/IGARSS46834.2022.9883799 %T A Calibration-Free Methodology to Estimate Significant Wave Height Using Time-Sequences of X-Band Marine Radar Images %U https://doi.org/10.1109/IGARSS46834.2022.9883799 %X This research applies a calibration-free method to estimate the significant wave height (Hs) using the amplitude of the electromagnetic signal acquired by a coherent on receive X-Band radar that operates in horizontal polarization. The ex-periments were conducted from 8th to 11 th November 2015 at the research platform FINO-3 located in the German Bight of the southern North Sea. Unlike the traditional wave disper-sion based procedure, the proposed method uses other filtering and signal processing techniques to invert the sea surface elevation from the sea clutter radar images. The compari-son of radar-derived Hs to in-situ measurements collected by a waver rider buoy resulted in a root mean square error of 0.33 m with a bias of 0.09 m and a correlation coefficient of r=0.92 . Validation of Hs estimates considering the AWAC measurements shows a RMSE of 0.24 m with a bias of 0.18 m and r=0.96 . Therefore, this calibration free methodol-ogy is very well suited to be applied to X-Band marine radars operated from offshore platforms as well as ships. %0 journal article %@ 0044-7447 %A März, C., Freitas, F.S., Faust, J.C., Godbold, J.A., Henley, S.F., Tessin, A.C., Abbott, G.D., Airs, R., Arndt, S., Barnes, D.K.A., Grange, L.J., Gray, N.D., Head, I.M., Hendry, K.R., Hilton, R.G., Reed, A.J., Rühl, S., Solan, M., Souster, T.A., Stevenson, M.A., Tait, K., Ward, J., Widdicombe, S. %D 2022 %J Ambio %P 370-382 %R doi:10.1007/s13280-021-01638-3 %T Biogeochemical consequences of a changing Arctic shelf seafloor ecosystem %U https://doi.org/10.1007/s13280-021-01638-3 %X Unprecedented and dramatic transformations are occurring in the Arctic in response to climate change, but academic, public, and political discourse has disproportionately focussed on the most visible and direct aspects of change, including sea ice melt, permafrost thaw, the fate of charismatic megafauna, and the expansion of fisheries. Such narratives disregard the importance of less visible and indirect processes and, in particular, miss the substantive contribution of the shelf seafloor in regulating nutrients and sequestering carbon. Here, we summarise the biogeochemical functioning of the Arctic shelf seafloor before considering how climate change and regional adjustments to human activities may alter its biogeochemical and ecological dynamics, including ecosystem function, carbon burial, or nutrient recycling. We highlight the importance of the Arctic benthic system in mitigating climatic and anthropogenic change and, with a focus on the Barents Sea, offer some observations and our perspectives on future management and policy. %0 report %@ 1866-3192 %A Bussmann, I., Anselm, N., Brix, H., Fischer, P., Flöser, G., Geissler, F., Kamjunke, N. %D 2021 %J Berichte zur Polar- und Meeresforschung %R doi:10.48433/BzPM_0751_2021 %T The MOSES Sternfahrt Expeditions of the Research Vessels ALBIS, LITTORINA, LUDWIG PRANDTL, MYA II and UTHÖRN to the Elbe River, Elbe Estuary and German Bight in 2020 %U https://doi.org/10.48433/BzPM_0751_2021 %X SUMMARY AND ITINERARYBuilding on our cruises and experiences in 2019, we wanted to continue and expand the trips in 2020 (cf. BzPM_0741_2020). In discussion with colleagues from Modular Observation Solutions for Earth Systems (MOSES) and Program-oriented Funding (PoF) IV of the Helmholtz Association, the planned cruise in 2020 served as a joint test case for MOSES instrumentation, as well as the further establishment of the communication between the groups concerning preparation of common campaigns, planning of available equipment, determination of responsibilities and building collaborating teams to investigate processes across the compartments. A special focus was set on the intercalibration of sensors and parameters, by insisting on several inter-calibration times for most sensors, measuring at the same time and location.The data management will be challenging as data from marine institutes / sensors will have to be combined with terrestrial institutes / sensors. All sensors were registered in MOSES data management tool (https://moses-dmp.gfz-potsdam.de/) beforehand. The registration procedure had been considerably improved, now the applicability in practice was to be checked. All sensors and data are now linked in the new MOSES data discovery portal (https://moses-data.gfz-potsdam.de). The decisive factor for the southern North Sea (or German Bight) is which water body and with which constituents it arrives in the Tide-Elbe area and how it is further modified in this area. Thus, the idea arose to continuously trace a group of parameters from the beginnings of the Elbe to the North Sea. What are the main impact factors for terrestrial and coastal water quality during floods and low water periods? Data for a better understanding of the different branches of the relevant event chain were provided by investigations within the Elbe river catchment (starting at the Czech/German border), along the middle course, Tide-Elbe und Elbe estuary (German Bight). To follow the water from the Elbe our campaign started with the Albis (research vessel from the UFZ), travelling with the water velocity of the Elbe; from 4 to 12 August. As the water takes about 2 weeks to travel from Geesthacht to Cuxhaven at the river mouth, the next campaign started on 25 and 26 August 2020. The Ludwig Prandtl (HZG) started at ebb tide near Cuxhaven, thus reducing the marine influence and focusing on the Elbe water. The estuarine cruise was followed by the marine cruise, from 31 August to 3 September 2020 5Summary and Itinerarywith three coastal research vessels, covering a broad area within the German Bight. Different thematic teams were covering the various processes across the considered compartments: terrestrial waters, coastal and marine zones. The basic hydrographic parameters (temperature and conductivity or salinity) were measured by FerryBoxes and probes on the ships, with some instruments actually being passed from ship to ship. Similarly, atmospheric and dissolved greenhouse gases (CH4 and CO2) were measured throughout. To learn more about the phytoplankton or productivity of the water, chlorophyll a, turbidity and nutrients were also determined. The carbon cycle was continuously described with the parameters TA, DOC, POC and DIC (total alkalinity, dissolved and particulate organic carbon, and dissolved inorganic carbon).As improvement from the previous cruises, we extended the duration of our cruises. Thus, for Sternfahrt_5 we could cover a wide area for four days with three ships, even though Corona restrictions allowed only 4 scientists on board and partly restricted access to the vessels.Also, the problem of switching from “on the way” modus to vertical sampling has been solved as now all vessels have d-ship installed which provides exact timing of the stations and switches. This information is now incorporated into the O2A as actions, consequently the data can be easily separated.In the following chapters and the tables in the annex, we explain in more detail the set-up of the cruises and our experiences. All of our data are now deposited in the database athttps://sensor.awi.de and https://www.ufz.de/record/dmp. However, such complex set-up as in our combined Elbe-2020 cruises are not easily mirrored in the database, thus this cruise report should also help to use the obtained data and their meta data along the river Elbe and its estuary as well as in the southern North Sea. %0 journal article %@ 0094-8276 %A Macovei, V., Petersen, W., Brix, H., Voynova, Y. %D 2021 %J Geophysical Research Letters %N 11 %P e2021GL092645 %R doi:10.1029/2021GL092645 %T Reduced Ocean Carbon Sink in the South and Central North Sea (2014–2018) Revealed From FerryBox Observations %U https://doi.org/10.1029/2021GL092645 11 %X Surface seawater carbon dioxide partial pressure (pCO2) in the south-central North Sea was measured between 2014 and 2018 using FerryBox-integrated membrane sensors on ships-of-opportunity. Average annual pCO2 variability was biologically controlled, with thermal effects modulating its amplitude. Deseasonalized winter trends of seawater pCO2 were positive (4.4 ± 2.0–8.4 ± 2.9 µatm yr−1), biogeochemically driven, stronger than the atmospheric pCO2 trend, and more pronounced than previous analyses. The trends calculated including all deseasonalized monthly averages were even higher (9.7 ± 2.8–12.2 ± 1.4 µatm yr−1). During our investigation, the southern study area became a stronger source and the northern part became a weaker sink for atmospheric carbon. Overall, average sea-air CO2 flux in our study area, from the Skagerrak to the Southern Bight (53°N), changed from −0.75 ± 0.61 mmol m−2 day−1 in 2014 to +0.20 ± 0.96 mmol m−2 day−1 in 2018. %0 journal article %@ 2296-7745 %A Schulz-Stellenfleth, J., Foerderreuther, S., Horstmann, J., Staneva, J. %D 2021 %J Frontiers in Marine Science %P 648266 %R doi:10.3389/fmars.2021.648266 %T Optimisation of Parameters in a German Bight Circulation Model by 4DVAR Assimilation of Current and Water Level Observations %U https://doi.org/10.3389/fmars.2021.648266 %X Uncertain parameters in a 3D barotropic circulation model of the German Bight are estimated with a variational optimisation approach. Surface current measurements from a high frequency (HF) radar are used in combination with acoustic Doppler current profiler (ADCP) and tide gauge observations as input for a 4DVAR assimilation scheme. The required cost function gradients are estimated using an adjoint model code. The focus of the study is on systematic errors of the model with the control vector including parameters of the bathymetry, bottom roughness, open boundary forcing, meteorological forcing as well as the turbulence model. The model uses the same bathymetry, open boundary forcing, and metereological forcing as the operational model run at the Federal Maritime and Hydrographic Agency (BSH). The baroclinic BSH model is used as a reference to put the performance of the optimised model into perspective. It is shown that the optimised model has better agreement with HF radar data and tide gauge observations both within the fortnight training period and the test period 1 month later. Current profile measurements taken at two platforms indicate that both models have comparable error magnitudes at those locations. The optimised model was also compared with independent drifter data. In this case, drifter simulations based on the BSH model and the respective operational drift model including some surface wave effects were used as a reference. Again, these comparison showed very similar results overall, with some larger errors of the tuned model in very shallow areas, where no observations were used for the tuning and surface wave effects, which are only explicitly considered in the BSH model, play a more important role. The tuned model seems to be slightly more dissipative than the BSH model with more energy entering through the western boundary and less energy leaving toward the north. It also became evident that the 4DVAR cost function minimisation process is complicated by momentum advection, which leads to non-differentiable dependencies of the model with respect to the control vector. It turned out that the omission of momentum advection in the adjoint code still leads to robust estimates of descent directions. %0 journal article %@ 2296-7745 %A Callies, U., Kreus, M., Petersen, W., Voynova, Y. %D 2021 %J Frontiers in Marine Science %P 666653 %R doi:10.3389/fmars.2021.666653 %T On Using Lagrangian Drift Simulations to Aid Interpretation of in situ Monitoring Data %U https://doi.org/10.3389/fmars.2021.666653 %X One key challenge of marine monitoring programs is to reasonably combine information from different in situ observations spread in space and time. In that context, we suggest the use of Lagrangian transport simulations extending both forward and backward in time to identify the movements of water bodies from the time they were observed to the time of their synopsis. We present examples of how synoptic maps of salinity generated by this method support the identification and tracing of river plumes in coastal regions. We also demonstrate how we can use synoptic maps to delineate different water masses in coastal margins. These examples involve quasi-continuous observations of salinity taken along ferry routes. A third application is the synchronization of measurements between fixed stations and nearby moving platforms. Both observational platforms often see the same water body, but at different times. We demonstrate how the measurements from a fixed platform can be synchronized to measurements from a moving platform by taking into account simulation-based time shifts. %0 journal article %@ 2169-9275 %A Reverdin, G., Olivier, L., Foltz, G., Speich, S., Karstensen, J., Horstmann, J., Zhang, D., Laxenaire, R., Carton, X., Branger, H., Carrasco, R., Boutin, J. %D 2021 %J Journal of Geophysical Research : Oceans %N 4 %P e2020JC016981 %R doi:10.1029/2020JC016981 %T Formation and Evolution of a Freshwater Plume in the Northwestern Tropical Atlantic in February 2020 %U https://doi.org/10.1029/2020JC016981 4 %X In February 2020, a 120-km-wide freshwater plume was documented by satellite and in situ observations near the Demerara Rise (7°N/54°W-56°W). It was initially stratified in the upper 10 m with a freshwater content of 2–3 m of Amazon water distributed down to 40 m. On February 2nd, ship transects indicate an inhomogeneous shelf structure with a propagating front in its midst, whereas minimum salinity close to 30 pss was observed close to the shelf break on February 5th. The salinity minimum eroded in time but was still observed 13–16 days later with 33.3 pss minimum value up to 400 km from the shelf break. At this time, the mixed layer depth was close to 20 m. The off-shelf flow lasted 10 days, contributing to a plume area extending over 100,000 km2 and associated with a 0.15 Sv (106 m3 s−1) freshwater transport. The off-shelf plume was steered northward by a North Brazil Current ring up to 12°N and then extended westward toward the Caribbean Sea. Its occurrence followed 3 days of favorable wind direction closer to the Amazon estuary, which contributed to north-westward freshwater transport on the shelf. Other such events of freshwater transport in January–March are documented since 2010 in salinity satellite products in 7 out of 10 years, and in 6 of those years, they were preceded by a change in wind direction between the Amazon estuary and the Guianas favoring the north-westward freshwater transport toward the shelf break. %0 journal article %@ 0739-0572 %A Lund, B., Dai, H., Graber, H., Guigand, C., Haus, B., Lodise, J., Novelli, G., Özgökmen, T., Rebozo, M., Ryan, E., Carrasco, R., Horstmann, J., Streßer, M. %D 2021 %J Journal of Atmospheric and Oceanic Technology %N 9 %P 1441-1455 %R doi:10.1175/JTECH-D-20-0123.1 %T UAS current mapping: A wave-based heading and position correction %U https://doi.org/10.1175/JTECH-D-20-0123.1 9 %X Our unmanned aerial system (UAS) current mapping is based on optical video data of the sea surface. We use three-dimensional fast Fourier transform and least-squares fitting to measure the surface waves’ phase velocities and the currents via the linear dispersion relationship. Our UAS is a low-cost off-the-shelf quadcopter with inaccurate camera position and attitude measurements, which may cause spurious currents as large as the signal. We present a novel wave-based UAS heading and position correction, improving the image rectification accuracy by a factor of ~3.5 and the current measurements’ temporal repeatability by factors of 1.8 to 4.8. This validation study maps the currents at high spatiotemporal resolution (5 m and 4 s) across the ~700 m wide tidally dominated Bear Cut channel in Miami, Florida. The UAS currents are compared to flotsam tracks, obtained through automated UAS video object detection and tracking, drifter tracks, and acoustic Doppler current profiler measurements. The root-mean-square errors of the cross- and along-channel currents are better than 0.03 m/s for the flotsam comparison and better than 0.06 m/s for the drifter comparison; the latter revealed a 0.06 m/s along-wind bias due to wind- and wave-driven vertical current shear. UAS current mapping could be used to monitor river discharge, buoyant pollutants, or submesoscale fronts and eddies; the proposed wave-based heading and position correction enables its use in areas without ground control points. %0 journal article %@ 2296-7745 %A Birchill, A., Beaton, A., Hull, T., Kaiser, J., Mowlem, M., Pascal, R., Schaap, A., Voynova, Y., Williams, C., Palmer, M. %D 2021 %J Frontiers in Marine Science %P 698102 %R doi:10.3389/fmars.2021.698102 %T Exploring Ocean Biogeochemistry Using a Lab-on-Chip Phosphate Analyser on an Underwater Glider %U https://doi.org/10.3389/fmars.2021.698102 %X The ability to make measurements of phosphate (PO43-) concentrations at temporal and spatial scales beyond those offered by shipboard observations offers new opportunities for investigations of the marine phosphorus cycle. We here report the first in situ PO43- dataset from an underwater glider (Kongsberg Seaglider) equipped with a PO43- Lab-on-Chip (LoC) analyser. Over 44 days, a 120 km transect was conducted in the northern North Sea during late summer (August and September). Surface depletion of PO43- (<0.2 µM) was observed above a seasonal thermocline, with elevated, but variable concentrations within the bottom mixed layer (0.30-0.65 µM). Part of the variability in the bottom layer is attributed to the regional circulation and across shelf exchange, with the highest PO43- concentrations being associated with elevated salinities in northernmost regions, consistent with nutrient rich North Atlantic water intruding onto the shelf. Our study represents a significant step forward in AUV sensor capabilities and presents new capability to extend research into the marine phosphorous cycle and, when combined with other recent Lab-on-Chip developments, nutrient stoichiometry. %0 journal article %@ 0924-7963 %A Rühl, S., Thompson, C., Queiros, A., Widdicombe, S. %D 2021 %J Journal of Marine Systems %P 103595 %R doi:10.1016/j.jmarsys.2021.103595 %T Decadal patterns and trends in benthic-pelagic exchange processes %U https://doi.org/10.1016/j.jmarsys.2021.103595 %X In marine environments, the exchange of particles and solutes between the seafloor and overlying water column, known as benthic-pelagic (B/P) coupling is an important component in many biological and biogeochemical cycles. Key processes and drivers involved in this exchange display strongly seasonal variability, especially in temperate coastal environments. The magnitude and timings of these seasonal patterns however are not identical year-on-year, and the influence of this inter-annual variability on the rate and direction of B/P exchange, as well as the influence of longer term, multi-year trends, are less well understood. In this current study, multi-year temporal patterns of benthic-pelagic solute and particle exchange were investigated on the examples of particulate organic carbon and dissolved inorganic nitrogen time series data, to assess connections between inter- and multi-annual processes and characterize their nature and what drives them. To this end, a decadal (2009–2018) time-series dataset that combines biological, physical, meteorological and chemical measurements from the Western Channel Observatory, Plymouth, UK was analysed in combination with supplementary data from several environmental monitoring agencies. Time-series decomposition using seasonal decomposition with locally estimated scatterplot smoothing revealed that the main causes of inter-annual variability were extreme outlier events, some of which were influential enough to cause multi-annual trends. Stochastic meteorological and biological extremes, such as exceptional storms and phytoplankton blooms explained a large proportion of outlier events in the time series. Global-scale climatic fluctuations, such as North Atlantic Oscillation (NAO) and Southern Oscillation Index were reflected in benthic-pelagic exchange trends when they co-occurred in an additive manner (e.g. positive NAO and El Niño). The importance of multi-parameter long-term observatories, such as the Western Channel Observatory, is highlighted, and the use of transdisciplinary time-series datasets to identify individual events which have large ecosystem-level impacts is demonstrated. In order to identify and monitor long-term effects, such as climate trends or decadal global ocean cycles, multi-decadal sustained observations are of vital importance. %0 journal article %@ 2311-5521 %A Calil, P., Suzuki, N., Baschek, B., da Silveira, I. %D 2021 %J Fluids %N 2 %P 54 %R doi:10.3390/fluids6020054 %T Filaments, Fronts and Eddies in the Cabo Frio Coastal Upwelling System, Brazil %U https://doi.org/10.3390/fluids6020054 2 %X We investigate the dynamics of meso- and submesoscale features of the northern South Brazil Bight shelf region with a 500-m horizontal resolution regional model. We focus on the Cabo Frio upwelling center, where nutrient-rich, coastal waters are transported into the mid- and outer shelf, because of its importance for local and remote productivity. The Cabo Frio upwelling center undergoes an upwelling phase, from late September to March, and a relaxation phase, from April to early September. During the upwelling phase, an intense front around 200 km long and 20 km wide with horizontal temperature gradients as large as 8 ∘C over less than 10 km develops. A surface-intensified frontal jet of 0.7 ms−1 in the upper 20 m and velocities of around 0.3 ms−1 reaching down to 65 m depth makes this front a preferential cross-shelf transport pathway. Large vertical mixing and vertical velocities are observed within the frontal region. The front is associated with strong cyclonic vorticity and strong variance in relative vorticity, frequently with O(1) Rossby numbers. The dynamical balance within the front is between the pressure gradient, Coriolis and vertical mixing terms, which are induced both by the winds, during the upwelling season, and by the geostrophic frontal jet. Therefore, the frontal dynamics may be largely described as sum of Ekman and turbulent thermal wind balances. During the upwelling phase, a mix of barotropic and baroclinic instabilities dominates in the upwelling center. However, these instabilities do not lead to the local formation of coherent eddies when the front is strong. In the relaxation phase, the front vanishes, and the water column becomes less stratified. The interaction between eastward coastal currents generated by sea level variability, coastal intrusions of the Brazil Current, and sporadic wind-driven, coastal upwelling events induce the formation of cyclonic eddies with diameters of, approximately, 20 km. They are in gradient-wind balance and propagate along the 100-m isobath on the shelf. During this phase baroclinic instability dominates. Cold filaments with widths of 2 km are formed due to straining and stretching of cold, coastal temperature anomalies. They last for a few days and are characterized by downwelling as large as 1 cms−1. The turbulent thermal wind balance provides a good first order estimate of the dynamical balance within the filament, but vertical and horizontal advection are shown to be important. To our knowledge, this is the first account of these smaller scale features in the region. Because these meso- and submesoscale features on the shelf heavily affect the water properties crucial to productivity of the South Brazil Bight, it is important to take these features into account for a better understanding of the functioning of this ecosystem and its resilience to both direct human activities as well as to climate change. %0 journal article %@ 2072-4292 %A Manso-Navarte, I., Rubio, A., Jorda, G., Carpenter, J., Merckelbach, L., Caballero, A. %D 2021 %J Remote Sensing %N 4 %P 674 %R doi:10.3390/rs13040674 %T Three-Dimensional Characterization of a Coastal Mode-Water Eddy from Multiplatform Observations and a Data Reconstruction Method %U https://doi.org/10.3390/rs13040674 4 %X Coastal mesoscale eddies are important oceanic structures partially responsible for regulating ocean-shelf exchanges. However, their description and characterization are challenging; observations are often too scarce for studying their physical properties and environmental impacts at the required spatio-temporal resolution. Therefore, models and data extrapolation methods are key tools for this purpose. Observations from high-frequency radar, one satellite and two gliders, are used here to better characterize the three-dimensional structure of a coastal mode-water eddy from a multiplatform approach in the southeastern Bay of Biscay in spring 2018. After the joint analysis of the observations, a three-dimensional data reconstruction method is applied to reconstruct the eddy current velocity field and estimate the associated water volume transport. The target eddy is detected by surface observations (high-frequency radar and satellite) for two weeks and presents similar dimensions and lifetimes as other eddies studied previously in the same location. However, this is the first time that the water column properties are also observed for this region, which depicts a mode-water eddy behavior, i.e., an uplift of the isopycnals in the near-surface and a downlift deeper in the water column. The reconstructed upper water column (1–100 m) eddy dynamics agree with the geostrophic dynamics observed by one of the gliders and result in cross-shelf inshore (offshore) volume transports between 0.04 (−0.01) and 0.15 (−0.11) Sv. The multiplatform data approach and the data reconstruction method are here highlighted as useful tools to characterize and three-dimensionally reconstruct coastal mesoscale processes in coastal areas. %0 journal article %@ 2296-7745 %A Carlson, D.F., Carr, G., Crosbie, J.L., Lundgren, P., Peissel, N., Pett, P., Turner, W., Rysgaard, S. %D 2021 %J Frontiers in Marine Science %P 665582 %R doi:10.3389/fmars.2021.665582 %T The 2017 Mission Arctic Citizen Science Sailing Expedition Conductivity, Temperature, and Depth Profiles in Western Greenland and Baffin Bay %U https://doi.org/10.3389/fmars.2021.665582 %X %0 journal article %@ 0146-9592 %A Harmel, T., Agagliate, J., Hieronymi, M., Gernez, P. %D 2021 %J Optics Letters %N 8 %P 1860-1863 %R doi:10.1364/OL.420344 %T Two-term Reynolds–McCormick phase function parameterization better describes light scattering by microalgae and mineral hydrosols %U https://doi.org/10.1364/OL.420344 8 %X The presence of hydrosols, taken as suspension of micro- or macroscopic material in water, strongly alters light propagation and thus the radiance distribution within a natural or artificial water volume. Understanding of hydrosols’ impacts on light propagation is limited by our ability to accurately handle the angular scattering phase function inherent to complex material such as suspended sediments or living cells. Based on actual quality-controlled measurements of sediments and microalgae, this Letter demonstrates the superiority of a two-term five-parameter empirical phase function as recently proposed for scattering by nanoparticle layers [Nanoscale 11, 7404 (2019) [Cro. The use of such phase function parameterizations presents new potentialities for various radiative transfer and remote sensing applications related to an aquatic environment. %0 online contribution %@ %A Eschenbach, C. %D 2021 %J Earth System Knowledge Platform [eskp.de] %R doi:10.48440/eskp.059 %T Offshore-Windkraftanlagen verwirbeln Wasser und Luft %U https://doi.org/10.48440/eskp.059 %X Offshore-Windkraftanlagen stehen im ständig bewegten Meerwasser und im Wind. Dort entnehmen sie Energie aus der Umwelt. Was aber macht das mit der Umwelt, mit der Luft und dem Wasser in ihrer direkten und weiteren Umgebung? %0 journal article %@ 0094-8276 %A Thomson, J., Lund, B., Hargrove, J., Smith, M., Horstmann, J., MacKinnon, J. %D 2021 %J Geophysical Research Letters %N 3 %P e2020GL090735 %R doi:10.1029/2020GL090735 %T Wave‐Driven Flow Along a Compact Marginal Ice Zone %U https://doi.org/10.1029/2020GL090735 3 %X Observations of surface waves and ice drift along a compact sea ice edge demonstrate the importance of waves in a marginal ice zone. An analytic model is presented for the along‐ice drift forced by the radiation stress gradient of oblique waves. A momentum balance using quadratic drag to oppose the wave forcing is sufficient to explain the observations. Lateral shear stresses in the ice are also evaluated, though this balance does not match the observations as well. Additional forcing by local winds is included and is small relative to the wave forcing. However, the wave forcing is isolated to a narrow region around 500‐m wide, whereas the wind forcing has effects on larger scales. The simplistic drag is assessed using observations of shear and turbulent dissipation rates. The results have implications for the shape and evolution of the ice edge, because the lateral shear may be a source of instabilities. %0 journal article %@ 0022-3670 %A Scheifele, B., Waterman, S., Carpenter, J. %D 2021 %J Journal of Physical Oceanography %N 1 %P 169-186 %R doi:10.1175/JPO-D-20-0057.1 %T Turbulence and Mixing in the Arctic Ocean’s Amundsen Gulf %U https://doi.org/10.1175/JPO-D-20-0057.1 1 %X This study uses CTD and microstructure measurements of shear and temperature from 348 glider profiles to characterize turbulence and turbulent mixing in the southeastern Beaufort Sea, where turbulence observations are presently scarce. We find that turbulence is typically weak: the turbulent kinetic energy dissipation rate, ε, has a median value (with 95% confidence intervals) of 2.3 (2.2, 2.4) × 10−11 W kg−1 and is less than 1.0×10−10 W kg−1 in 68% of observations. Variability in ε spans five orders of magnitude, with indications that turbulence is bottom enhanced and modulated in time by the semidiurnal tide. Stratification is strong and frequently damps turbulence, inhibiting diapycnal mixing. Buoyancy Reynolds number estimates suggest that turbulent diapycnal mixing is unlikely in 93% of observations; however, a small number of strongly turbulent mixing events are disproportionately important in determining net buoyancy fluxes. The arithmetic mean diapycnal diffusivity of density is 4.5 (2.3, 14) ×10−6 m2 s−1, three orders of magnitude larger than that expected from molecular diffusion. Vertical heat fluxes are modest at O(0.1) W m−2, of the same order of magnitude as those in the Canada Basin double-diffusive staircase, however, staircases are generally not observed. Despite significant heat present in the Pacific Water layer in the form of a warm-core mesoscale eddy and smaller, O(1) km, temperature anomalies, turbulent mixing was found to be too low to release this heat to shallower depths. %0 journal article %@ 0022-3670 %A Becherer, J., Moum, J., Calantoni, J., Colosi, J., Barth, J., Lerczak, J., McSweeney, J., MacKinnon, J., Waterhouse, A. %D 2021 %J Journal of Physical Oceanography %N 8 %P 2565-2582 %R doi:10.1175/JPO-D-21-0047.1 %T Saturation of the Internal Tide over the Inner Continental Shelf. Part II: Parameterization %U https://doi.org/10.1175/JPO-D-21-0047.1 8 %X Here, we develop a framework for understanding the observations presented in Part I. In this framework, the internal tide saturates as it shoals as a result of amplitude limitation with decreasing water depth H. From this framework evolves estimates of averaged energetics of the internal tide; specifically, energy ⟨APE⟩, energy flux ⟨FE⟩, and energy flux divergence ∂x⟨FE⟩. Since we observe that dissipation ⟨D⟩ ≈ ∂x⟨FE⟩, we also interpret our estimate of ∂x⟨FE⟩ as ⟨D⟩. These estimates represent a parameterization of the energy in the internal tide as it saturates over the inner continental shelf. The parameterization depends solely on depth-mean stratification and bathymetry. A summary result is that the cross-shelf depth dependencies of ⟨APE⟩, ⟨FE⟩, and ∂x⟨FE⟩ are analogous to those for shoaling surface gravity waves in the surf zone, suggesting that the inner shelf is the surf zone for the internal tide. A test of our simple parameterization against a range of datasets suggests that it is broadly applicable. %0 journal article %@ 2169-9275 %A Napolitano, D., da Silveira, I., Tandon, A., Calil, P. %D 2021 %J Journal of Geophysical Research : Oceans %N 1 %P e2020JC016731 %R doi:10.1029/2020JC016731 %T Submesoscale Phenomena Due to the Brazil Current Crossing of the Vitória‐Trindade Ridge %U https://doi.org/10.1029/2020JC016731 1 %X At 20.5°S, the Brazil Current and the Intermediate Western Boundary Current interact with a quasi‐zonal seamount chain, the Vitória‐Trindade Ridge (VTR). While the mesoscale variability generated due to these western boundary currents crossing the VTR has been recently studied, the submesoscale dynamics associated with such features have never been addressed. Here, we use new observations and a 2‐ km‐resolution model to analyze the role of the VTR seamounts in the regional submesoscale dynamics, their seasonality, and instabilities. We present new high‐resolution velocity and density observations that capture submesoscale features associated with the flow. Within these regions, potential vorticity (PV) reveals patches of symmetrically unstable flow close to seamounts. The horizontal resolution (Δx ≃ 1.5 km) of our quasi‐synoptic observations (10 h) partially resolves submesoscale instabilities. Our Regional Oceanic Modeling System simulation identifies two regimes of submesoscale activity in the region, one typically associated with the seasonal cycle of the mixed layer, and a second associated with flow–topography interactions. A spatiotemporal analysis of the vertical buoyancy fluxes points to these flow–topography interactions as the main source of recurrent, deeper instabilities. As the VTR emerges as a submesoscale hotspot in the oligotrophic South Atlantic, the lack of observations still remains the main obstacle to better understand submesoscale processes in the region. %0 journal article %@ 1541-5856 %A Macovei, V., Voynova, Y., Becker, M., Triest, J., Petersen, W. %D 2021 %J Limnology and Oceanography: Methods %N 1 %P 37-50 %R doi:10.1002/lom3.10403 %T Long‐term intercomparison of two pCO2 instruments based on ship‐of‐opportunity measurements in a dynamic shelf sea environment %U https://doi.org/10.1002/lom3.10403 1 %X The partial pressure of carbon dioxide (pCO2) in surface seawater is an important biogeochemical variable because, together with the pCO2 in the atmosphere, it determines the direction of air–sea carbon dioxide exchange. Large‐scale observations of pCO2 are facilitated by Ships‐of‐Opportunity (SOOP‐CO2) equipped with underway measuring instruments. The need for expanding the observation capacity and the challenges involving the sustainability and maintenance of traditional equilibrator systems led the community toward developing simpler and more autonomous systems. Here we performed a comparison between a membrane‐based sensor and a showerhead equilibration sensor installed on two SOOP‐CO2 between 2013 and 2018. We identified time‐ and space‐adequate crossovers in the Skagerrak Strait, where the two ship routes often crossed. We found a mean total difference of 1.5 ± 10.6 μatm and a root mean square error of 11 μatm. The pCO2 values recorded by the two instruments showed a strong linear correlation with a coefficient of 0.91 and a slope of 1.07 (± 0.14), despite the dynamic nature of the environment and the difficulty of comparing measurements from two different vessels. The membrane‐based sensor was integrated with a FerryBox system on a ship with a high sampling frequency in the study area. We showed the strength of having a sensor‐based network with a high spatial coverage that can be validated against conventional SOOP‐CO2 methods. Proving the validity of membrane‐based sensors in coastal and continental shelf seas and using the higher frequency measurements they provide can enable a thorough characterization of pCO2 variability in these dynamic environments. %0 journal article %@ 0022-3670 %A Becherer, J., Moum, J., Calantoni, J., Colosi, J., Barth, J., Lerczak, J., McSweeney, J., MacKinnnon, J., Waterhouse, A. %D 2021 %J Journal of Physical Oceanography %N 8 %P 2553-2563 %R doi:10.1175/JPO-D-20-0264.1 %T Saturation of the Internal Tide over the Inner Continental Shelf. Part I: Observations %U https://doi.org/10.1175/JPO-D-20-0264.1 8 %X Broadly distributed measurements of velocity, density, and turbulence spanning the inner shelf off central California indicate that (i) the average shoreward-directed internal tide energy flux ⟨FE⟩ decreases to near 0 at the 25-m isobath; (ii) the vertically integrated turbulence dissipation rate ⟨D⟩ is approximately equal to the flux divergence of internal tide energy ∂x⟨FE⟩; (iii) the ratio of turbulence energy dissipation in the interior relative to the bottom boundary layer (BBL) decreases toward shallow waters; (iv) going inshore, ⟨FE⟩ becomes decorrelated with the incoming internal wave energy flux; and (v) ⟨FE⟩ becomes increasingly correlated with stratification toward shallower water. %0 journal article %@ 0022-1120 %A Yousefi, K., Veron, F., Buckley, M. %D 2021 %J Journal of Fluid Mechanics %P A33 %R doi:10.1017/jfm.2021.377 %T Turbulent and wave kinetic energy budgets in the airflow over wind-generated surface waves %U https://doi.org/10.1017/jfm.2021.377 %X The momentum and energy exchanges at the ocean surface are central factors determining the sea state, weather patterns and climate. To investigate the effects of surface waves on the air–sea energy exchanges, we analyse high-resolution laboratory measurements of the airflow velocity acquired above wind-generated surface waves using the particle image velocimetry technique. The velocity fields were further decomposed into the mean, wave-coherent and turbulent components, and the corresponding energy budgets were explored in detail. We specifically focused on the terms of the budget equations that represent turbulence production, wave production and wave–turbulence interactions. Over wind waves, the turbulent kinetic energy (TKE) production is positive at all heights with a sharp peak near the interface, indicating the transfer of energy from the mean shear to the turbulence. Away from the surface, however, the TKE production approaches zero. Similarly, the wave kinetic energy (WKE) production is positive in the lower portion of the wave boundary layer (WBL), representing the transfer of energy from the mean flow to the wave-coherent field. In the upper part of the WBL, WKE production becomes slightly negative, wherein the energy is transferred from the wave perturbation to the mean flow. The viscous and Stokes sublayer heights emerge as natural vertical scales for the TKE and WKE production terms, respectively. The interactions between the wave and turbulence perturbations show an energy transfer from the wave to the turbulence in the bulk of the WBL and from the turbulence to the wave in a thin layer near the interface. %0 online contribution %@ %A Eschenbach, C. %D 2021 %J Earth System Knowledge Platform [eskp.de] %R doi:10.48440/eskp.063 %T Korrosionsschutz für Offshore-Windkraft : Problem für die Umwelt? %U https://doi.org/10.48440/eskp.063 %X Offshore-Windkraftanlagen produzieren zuverlässig Strom. In Deutschland haben sie im Jahr 2020 etwa 27 Milliarden Kilowattstunden Strom geliefert. Die Anlagen setzen jedoch auch ständig chemische Stoffe in das Wasser und die sie umgebenden Sedimente frei: Aluminium, Zink und zahlreiche andere (potentiell) giftige Schwermetalle stammen vor allem aus dem Korrosionsschutz der Anlagen. Aktuelle Untersuchungen gehen der Frage nach, inwiefern Windkraftanlagen Schadstoffe abgeben und welche Auswirkungen das mittel- bis langfristig auf die Meeresumwelt hat. %0 book part %@ 2522-8692 %A Horstmann, J., Dzvonkovskaya, A. %D 2021 %J Springer Handbook of Atmospheric Measurements %P 953-968 %R doi:10.1007/978-3-030-52171-4_33 %T High Frequency Radar %U https://doi.org/10.1007/978-3-030-52171-4_33 %X High frequency (HF) radars operate at radio frequencies between 3 and 30 MHz, where electromagnetic waves have the ability to propagate along the ocean surface and therefore to obtain information beyond the horizon. All the information measured by a HF radar corresponds to physical parameters of the upper couple of meters of the ocean surface. Today, HF radar systems are typically used along the coast, as they offer the unique opportunity to monitor the coastal area within a distance of 40 – 200 km. A HF radar system transmits electromagnetic waves and measures the backscatter intensity and speed of ocean waves. This information is primarily used to estimate surface currents and ocean wave properties. However, in the last decade, HF radars have also been shown to be extremely useful for several other applications such as surface wind measurements and tsunami monitoring, as well as vessel traffic support. %0 dataset %@ %A Macovei, V., Voynova, Y., Gehrung, M., Petersen, W. %D 2021 %J PANGAEA %R doi:10.1594/PANGAEA.930383 %T Ship-of-Opportunity, FerryBox-integrated, membrane-based sensor pCO2, temperature and salinity measurements in the surface North Sea since 2013 %U https://doi.org/10.1594/PANGAEA.930383 %X The submitted datasets contain surface seawater partial pressure of carbon dioxide (pCO2) values measured with Kongsberg Contros/4H-Jena HydroC-FT membrane-based sensors. These sensors were integrated on the FerryBoxes installed on commercial vessels travelling in the North Sea and maintained by the Institute of Coastal Ocean Dynamics at the Helmholtz-Zentrum Hereon, Germany. The pCO2 data were reprocessed from the raw data and corrected for sensor post-calibration where this was available. The instrument produces a result every second. 20-second averages are used for calculations and reported. Temperature and salinity results are also provided where available. These were measured from the underway with Falmouth Scientific Instruments / Teledyne Instruments sensors also integrated with the FerryBox. The sensors were regularly maintained and occasionally replaced. Each sensor replacement results in a new dataset within this publication series. The files are named using the ship name and date of the first measurement. %0 journal article %@ 0094-8276 %A Bjørnestad, M., Buckley, M., Kalisch, H., Streßer, M., Horstmann, J., Frøysa, H.G., Ige, O.E., Cysewski, M., Carrasco-Alvarez, R. %D 2021 %J Geophysical Research Letters %N 21 %P e2021GL095722 %R doi:10.1029/2021GL095722 %T Lagrangian Measurements of Orbital Velocities in the Surf Zone %U https://doi.org/10.1029/2021GL095722 21 %X Eulerian and Lagrangian measurements of orbital velocities in waves approaching a beach are analyzed with the goal of understanding the relative influence of wave-by-wave variations in mean-water level, wave height and incipient wave breaking on mass transport properties of waves in the surf zone. It is shown quantitatively that elevated local mean-water level correlates positively with increased Lagrangian mass transport at the free surface. Eulerian ADV measurements in the fluid column suggest that the depth-integrated wave-by-wave mass transport also correlates positively with the local mean-water level, and is only weakly linked to wave height and wave-breaking events. %0 journal article %@ 2296-7745 %A Fischer, P., Dietrich, P., Achterberg, E., Anselm, N., Brix, H., Bussmann, I., Eickelmann, L., Flöser, G., Friedrich, M., Rust, H., Schütze, C., Koedel, U. %D 2021 %J Frontiers in Marine Science %P 770977 %R doi:10.3389/fmars.2021.770977 %T Effects of Measuring Devices and Sampling Strategies on the Interpretation of Monitoring Data for Long-Term Trend Analysis %U https://doi.org/10.3389/fmars.2021.770977 %X A thorough and reliable assessment of changes in sea surface water temperatures (SSWTs) is essential for understanding the effects of global warming on long-term trends in marine ecosystems and their communities. The first long-term temperature measurements were established almost a century ago, especially in coastal areas, and some of them are still in operation. However, while in earlier times these measurements were done by hand every day, current environmental long-term observation stations (ELTOS) are often fully automated and integrated in cabled underwater observatories (UWOs). With this new technology, year-round measurements became feasible even in remote or difficult to access areas, such as coastal areas of the Arctic Ocean in winter, where measurements were almost impossible just a decade ago. In this context, there is a question over what extent the sampling frequency and accuracy influence results in long-term monitoring approaches. In this paper, we address this with a combination of lab experiments on sensor accuracy and precision and a simulated sampling program with different sampling frequencies based on a continuous water temperature dataset from Svalbard, Arctic, from 2012 to 2017. Our laboratory experiments showed that temperature measurements with 12 different temperature sensor types at different price ranges all provided measurements accurate enough to resolve temperature changes over years on a level discussed in the literature when addressing climate change effects in coastal waters. However, the experiments also revealed that some sensors are more suitable for measuring absolute temperature changes over time, while others are more suitable for determining relative temperature changes. Our simulated sampling program in Svalbard coastal waters over 5 years revealed that the selection of a proper sampling frequency is most relevant for discriminating significant long-term temperature changes from random daily, seasonal, or interannual fluctuations. While hourly and daily sampling could deliver reliable, stable, and comparable results concerning temperature increases over time, weekly sampling was less able to reliably detect overall significant trends. With even lower sampling frequencies (monthly sampling), no significant temperature trend over time could be detected. Although the results were obtained for a specific site, they are transferable to other aquatic research questions and non-polar regions. %0 report %@ %A Le Traon, P., Abadie, V., Ali, A., Behrens, A., Staneva, J., Hieronymi, M., Krasemann, H. %D 2021 %J %R doi:10.48670/moi-cafr-n813 %T The Copernicus Marine Service from 2015 to 2021: six years of achievements %U https://doi.org/10.48670/moi-cafr-n813 %X This report and summary offer information on the achievements of the Copernicus Marine Service during the 2015-2021 period. The information is collected from the Mercator Ocean Journal Special Issue #57 as well as the Copernicus Marine General Assembly conference in January 2021. The components of the service include, data producers, central information and dissemination systems, user services, along with cross-cutting coordination activities (scientific evolution, product quality, multi-year processing, ocean reporting and user uptake). The summary of this report is designed to show a synthesised review of the report and is designed for policymakers and the general public. %0 conference paper %@ %A Macovei, V., Voynova, Y., Becker, M., Triest, J., Petersen, W. %D 2021 %J Advances in operational oceanography : expanding Europe's ocean observing and forecasting capacity : Proceedings of the 9th EuroGOOS International Conference %P 30-33 %R doi:10.13155/83160 %T An instrument intercomparison exercise in the Skagerrak allows extending the FerryBox pCO2 observational coverage across the Central and Southern North Sea %U https://doi.org/10.13155/83160 %X oceans and dynamic coastal seas. %0 journal article %@ 0022-3670 %A Spydell, M.S., Suanda, S.H., Grimes, D.J., Becherer, J., McSweeney, J.M., Chickade, C., Moulton, M., Thomson, J., Lerczak, J., Barth, J., Macmahan, J., Colosi, J., Romeiser, R., Waterhouse, A.F., Calantoni, J., Feddersen, F. %D 2021 %J Journal of Physical Oceanography %N 12 %P 3629-3650 %R doi:10.1175/JPO-D-21-0095.1 %T Internal Bore Evolution across the Shelf near Pt. Sal, California, Interpreted as a Gravity Current %U https://doi.org/10.1175/JPO-D-21-0095.1 12 %X Off the central California coast near Pt. Sal, a large-amplitude internal bore was observed for 20 h over 10 km cross shore, or 100–10-m water depth (D), and 30 km along coast by remote sensing, 39 in situ moorings, ship surveys, and drifters. The bore is associated with steep isotherm displacements representing a significant fraction of D. Observations were used to estimate bore arrival time tB, thickness h, and bore and nonbore (ambient) temperature difference ΔT, leading to reduced gravity g′. Bore speeds c, estimated from mapped tB, varied from 0.25 to 0.1 m s−1 from D = 50 to 10 m. The h varied from 5 to 35 m, generally decreased with D, and varied regionally along isobath. The bore ΔT varied from 0.75° to 2.15°C. Bore evolution was interpreted from the perspective of a two-layer gravity current. Gravity current speeds U, estimated from the local bore h and g′, compared well to observed bore speeds throughout its cross-shore propagation. Linear internal wave speeds based on various stratification estimates result in larger errors. On average bore thickness h = D/2, with regional variation, suggesting energy saturation. From 50- to 10-m depths, observed bore speeds compared well to saturated gravity current speeds and energetics that depend only on water depth and shelf-wide mean g′. This suggests that this internal bore is the internal wave analog to a saturated surfzone surface gravity bore. Along-coast variations in prebore stratification explain variations in bore properties. Near Pt. Sal, bore Doppler shifting by barotropic currents is observed. %0 preprint %@ %A Onken, R., Baschek, B. %D 2021 %J Ocean Science Discussions %R doi:10.5194/os-2021-86 %T Properties and evolution of a submesoscale cyclonic spiral %U https://doi.org/10.5194/os-2021-86 %X The evolution of a submesoscale cyclonic spiral of 1 km in diameter is simulated with ROMS (Regional Ocean Modeling System) using 33.3 m horizontal resolution in a triple-nested configuration. The generation of the spiral starts from a dense filament that is rolled into a vortex and detaches from the filament. During spin-up, extreme values are attained by various quantities, that are organized in single-arm and multi-arm spirals. The spin-down starts when the cyclone separates from the filament. At the same time, the horizontal speed develops a dipole-like pattern and isotachs form closed contours around the vortex center. The amplitudes of most quantities decrease significantly, but the instantaneous vertical velocity w exhibits high-frequency oscillations and more pronounced extremes than during spin-up. The oscillations are due to vortex Rossby waves (VRWs), that circle the eddy counterclockwise and generate multi-arm spirals with alternating signs by means of azimuthal vorticity advection. Experiments with virtual surface drifters and isopycnal floats indicate downwelling everywhere near the surface. The downwelling is most intense in the center of the spiral at all depth levels, leading to a radial outflow in the thermocline and weak upwelling at the periphery. This overturning circulation is driven by convergent near-surface flow and associated subduction of isopycnals. While the downwelling in the center may support the export of particulate organic carbon from the mixed layer into the main thermocline, the upwelling at the periphery effectuates an upward isopycnal transport of nutrients, enhancing the growth of phytoplankton in the euphotic zone. %0 journal article %@ 0303-2434 %A Lehmann, M., Schütt, E., Hieronymi, M., Dare, J., Krasemann, H. %D 2021 %J International Journal of Applied Earth Observation and Geoinformation %P 102547 %R doi:10.1016/j.jag.2021.102547 %T Analysis of recurring patchiness in satellite-derived chlorophyll a to aid the selection of representative sites for lake water quality monitoring %U https://doi.org/10.1016/j.jag.2021.102547 %X Horizontal patchiness of water quality attributes in lakes substantially influences the ability to accurately determine an average condition of a lake from traditional in situ sampling. Therefore, spatial variability has to be accounted for in monitoring programmes which aim at determining the states and trends of ecosystem attributes. We used five years of Sentinel-2 Multispectral Instrument (MSI) data and conducted spatial analyses of surface chlorophyll a (Chl) concentration to map its variability and provide concrete recommendations for resource managers to design in situ sampling programmes. First, we developed a regional calibration of Chl predictions by C2RCC, an openly available processor for atmospheric corrections and water constituent retrieval, using in situ data from eleven temperate lakes in the central North Island of Aotearoa New Zealand. Using 93 match-up samples, we re-fitted C2RCC’s partitioning of constituent absorption coefficients to achieve an improved prediction accuracy for Chl (r2 = 0.79, root mean square error = 5.4 mg m−3). The new relationship was applied to all cloud-free images for thirteen regional lakes for further spatial analysis. We found that the medians calculated within areas of different sizes around in situ sampling locations may increase or decrease, illustrating an unpredictable uncertainty of the representativeness of any in situ sample. We went on to summarise five years of spatial variability by assessing each pixel for its tendency to be near the lake median Chl, higher (near the upper quartile) or lower (near the lower quartile). This spatiotemporal analysis revealed recurring patchiness that we converted to an indication of the representativeness of any location in the lake useful for the selection of more representative sites for future monitoring programmes. %0 journal article %@ 0022-3670 %A Funke, C., Buckley, M., Schultze, L., Veron, F., Timmermans, M., Carpenter, J. %D 2021 %J Journal of Physical Oceanography %N 11 %P 3449-3460 %R doi:10.1175/JPO-D-20-0311.1 %T Pressure Fields in the Airflow over Wind-Generated Surface Waves %U https://doi.org/10.1175/JPO-D-20-0311.1 11 %X The quantification of pressure fields in the airflow over water waves is fundamental for understanding the coupling of the atmosphere and the ocean. The relationship between the pressure field, and the water surface slope and velocity, are crucial in setting the fluxes of momentum and energy. However, quantifying these fluxes is hampered by difficulties in measuring pressure fields at the wavy air-water interface. Here we utilise results from laboratory experiments of wind-driven surface waves. The data consist of particle image velocimetry of the airflow combined with laser-induced fluorescence of the water surface. These data were then used to develop a pressure field reconstruction technique based on solving a pressure Poisson equation in the airflow above water waves. The results allow for independent quantification of both the viscous stress and pressure-induced form drag components of the momentum flux. Comparison of these with an independent bulk estimate of the total momentum flux (based on law-of-the-wall theory) shows that the momentum budget is closed to within approximately 5%. In the partitioning of the momentum flux between viscous and pressure drag components, we find a greater influence of form drag at high wind speeds and wave slopes. An analysis of the various approximations and assumptions made in the pressure reconstruction, along with the corresponding sources of error, is also presented. %0 journal article %@ 0022-3670 %A Liang, Y., Carpenter, J., Timmermans, M. %D 2021 %J Journal of Physical Oceanography %N 11 %P 3335-3346 %R doi:10.1175/JPO-D-21-0060.1 %T The effect of rotation on double diffusive convection: perspectives from linear stability analysis %U https://doi.org/10.1175/JPO-D-21-0060.1 11 %X Diffusive convection can occur when two constituents of a stratified fluid have opposing effects on its stratification and different molecular diffusivities. This form of convection arises for the particular temperature and salinity stratification in the Arctic Ocean and is relevant to heat fluxes. Previous studies have suggested that planetary rotation may influence diffusive-convective heat fluxes, although the precise physical mechanisms and regime of rotational influence are not well understood. A linear stability analysis of a temperature and salinity interface bounded by two mixed layers is performed here to understand the stability properties of a diffusive-convective system, and in particular the transition from non-rotating to rotationally-controlled heat transfer. Rotation is shown to stabilize diffusive convection by increasing the critical Rayleigh number to initiate instability. In the rotationally-controlled regime, a −4/3 power law is found between the critical Rayleigh number and the Ekman number, similar to the scaling for rotating thermal convection. The transition from non-rotating to rotationally-controlled convection, and associated drop in heat fluxes, is predicted to occur when the thermal interfacial thickness exceeds about 4 times the Ekman layer thickness. A vorticity budget analysis indicates how baroclinic vorticity production is counteracted by the tilting of planetary vorticity by vertical shear, which accounts for the stabilization effect of rotation. Finally, direct numerical simulations yield generally good agreement with the linear stability analysis. This study, therefore, provides a theoretical framework for classifying regimes of rotationally-controlled diffusive-convective heat fluxes, such as may arise in some regions of the Arctic Ocean. %0 journal article %@ 2296-7745 %A Bussmann, I., Brix, H., Flöser, G., Ködel, U., Fischer, P. %D 2021 %J Frontiers in Marine Science %P 728308 %R doi:10.3389/fmars.2021.728308 %T Detailed Patterns of Methane Distribution in the German Bight %U https://doi.org/10.3389/fmars.2021.728308 %X Although methane is a widely studied greenhouse gas, uncertainties remain with respect to the factors controlling its distribution and diffusive flux into the atmosphere, especially in highly dynamic coastal waters. In the southern North Sea, the Elbe and Weser rivers are two major tributaries contributing to the overall methane budget of the southern German Bight. In June 2019, we continuously measured methane and basic hydrographic parameters at a high temporal and spatial resolution (one measurement per minute every 200–300 m) on a transect between Cuxhaven and Helgoland. These measurements revealed that the overall driver of the coastal methane distribution is the dilution of riverine methane-rich water with methane-poor marine water. For both the Elbe and Weser, we determined an input concentration of 40–50 nmol/L compared to only 5 nmol/L in the marine area. Accordingly, we observed a comparatively steady dilution pattern of methane concentration toward the marine realm. Moreover, small-scale anomalous patterns with unexpectedly higher dissolved methane concentrations were discovered at certain sites and times. These patterns were associated with the highly significant correlations of methane with oxygen or turbidity. However, these local anomalies were not consistent over time (days, months). The calculated diffusive methane flux from the water into the atmosphere revealed local values approximately 3.5 times higher than background values (median of 36 and 128 µmol m-2 d-1). We evaluate that this occurred because of a combination of increasing wind speed and increasing methane concentration at those times and locations. Hence, our results demonstrate that improved temporal and spatial resolution of methane measurements can provide a more accurate estimation and, consequently, a more functional understanding of the temporal and spatial dynamics of the coastal methane flux. %0 journal article %@ 0739-0572 %A Merckelbach, L., Carpenter, J. %D 2021 %J Journal of Atmospheric and Oceanic Technology %N 7 %P 1265-1275 %R doi:10.1175/JTECH-D-20-0206.1 %T Ocean Glider Flight in the Presence of Surface Waves %U https://doi.org/10.1175/JTECH-D-20-0206.1 7 %X Autonomous, buoyancy-driven ocean gliders are increasingly used as a platform for the measurement of turbulence microstructure. In the processing of such measurements, there is a sensitive (quartic) dependence of the turbulence dissipation rate ϵ on the speed of flow past the sensors, or alternatively, the speed of the glider through the ocean water column. The mechanics of glider flight is therefore examined by extending previous flight models to account for the effects of ocean surface waves. It is found that due to the relatively small buoyancy changes used to drive gliders, the surface wave-induced motion, superimposed onto the steady-state motion, follows to a good approximation the motion of the wave orbitals. Errors expected in measuring ϵ at the ocean near-surface due to wave-induced relative velocities are generally less than 10%. However, pressure perturbations associated with the wave motion can cause significant perturbations in the glider-measured pressure signal and consequently also in the measured vertical glider velocity signal. This effect of surface waves is only present in the shallow water regime. It arises from an incomplete cancellation of the wave-induced pressure perturbation with the hydrostatic component due to vertical glider displacements, whereas for deep-water waves this cancellation is complete. %0 journal article %@ 1541-5856 %A Kostakis, I., Twardowski, M., Roesler, C., Röttgers, R., Stramski, D., McKee, D., Tonizzo, A., Drapeau, S. %D 2021 %J Limnology and Oceanography: Methods %N 9 %P 589-625 %R doi:10.1002/lom3.10447 %T Hyperspectral optical absorption closure experiment in complex coastal waters %U https://doi.org/10.1002/lom3.10447 9 %X Accurate measurements of absorption data are required for the development and validation of inversion algorithms for upcoming hyperspectral ocean color imaging sensors, such as the NASA Phytoplankton, Aerosol, Cloud, and ocean Ecosystem mission. This study aims to provide uncertainty estimates associated with leading approaches to measure hyperspectral absorption coefficients in complex coastal waters. Absorption spectra were collected at 12 different stations, all located in the Indian River Lagoon, Florida, USA, between 09 January 2017 and 13 January 2017. Measurements included spectral absorption coefficients in the visible range (400–700 nm) associated with dissolved, aCDOM, total particulate, ap, and total nonwater, anw, fractions, and were made both in situ and from discrete samples. Discrete sample approaches included dual-beam spectrophotometer, liquid waveguide capillary cell, point-source integrating cavity absorption meter (PSICAM) for dissolved matter absorption samples, and quantitative filter technique ICAM measurements and the dual-beam spectrophotometer with center-mounted integrating sphere filter pad technique, while the Turner Designs ICAM, and WET Labs AC-s, and AC-9 instruments were used to determine absorption coefficients in situ. The Gershun approach, determining absorption from measurement of the irradiance quartet with respect to depth was also assessed in situ. Measurement uncertainties and relative accuracies were quantified for each of these approaches. Results showed generally strong agreements between different discrete sample methods, with average percent absolute error %δabs < 7% for aCDOM and < 9% for ap. In situ approaches showed higher variability and reduced accuracy. For anw, %δabs deviation relative to PSICAM data was on average 12% to 20%. Results help identify remaining technological gaps and need for improvements in the different absorption measurement approaches. %0 journal article %@ 0308-597X %A Estes, M., Jr., Anderson, C., Appeltans, W., Bax, N., Bednaršek, N., Canonico, G., Djavidnia, S., Escobar, E., Fietzek, P., Gregoire, M., Hazen, E., Kavanaugh, M., Lejzerowicz, F., Lombard, F., Miloslavich, P., Möller, K.O., Monk, J., Montes, E., Moustahfid, H., Muelbert, M.M.C., Muller-Karger, F., Peavey Reeves, L.E., Satterthwaite, E.V., Schmidt, J.O., Sequeira, A.M.M., Turner, W., Weatherdon, L.V. %D 2021 %J Marine Policy %P 104699 %R doi:10.1016/j.marpol.2021.104699 %T Enhanced monitoring of life in the sea is a critical component of conservation management and sustainable economic growth %U https://doi.org/10.1016/j.marpol.2021.104699 %X Marine biodiversity is a fundamental characteristic of our planet that depends on and influences climate, water quality, and many ocean state variables. It is also at the core of ecosystem services that can make or break economic development in any region. Our purpose is to highlight the need for marine biological observations to inform science and conservation management and to support the blue economy. We provide ten recommendations, applicable now, to measure and forecast biological Essential Ocean Variables (EOVs) as part of economic monitoring efforts. The UN Decade of Ocean Science for Sustainable Development (2021–2030) provides a timely opportunity to implement these recommendations to benefit humanity and enable the USD 3 trillion global ocean economy expected by 2030. %0 journal article %@ 1424-8220 %A Horstmann, J., Bödewadt, J., Carrasco, R., Cysewski, M., Seemann, J., Streβer, M. %D 2021 %J Sensors %N 23 %P 7828 %R doi:10.3390/s21237828 %T A Coherent on Receive X-Band Marine Radar for Ocean Observations %U https://doi.org/10.3390/s21237828 23 %X Marine radars are increasingly popular for monitoring meteorological and oceanographic parameters such as ocean surface wind, waves and currents as well as bathymetry and shorelines. Within this paper a coherent on receive marine radar is introduced, which is based on an incoherent off the shelf pulsed X-band radar. The main concept of the coherentization is based on the coherent on receive principle, where the coherence is achieved by measuring the phase of the transmitted pulse from a leak in the radar circulator, which then serves as a reference phase for the transmitted pulse. The Doppler shift frequency can be computed from two consecutive pulse-pairs in the time domain or from the first moment of the Doppler spectrum inferred by means of a short time Fast Fourier Transform. From the Doppler shift frequencies, radial speed maps of the backscatter of the ocean surface are retrieved. The resulting backscatter intensity and Doppler speed maps are presented for horizontal as well as vertical polarization, and discussed with respect to meteorological and oceanographic applications. %0 journal article %@ 2169-9275 %A Lazaneo, C., Napolitano, D., da Silveira, I., Tandon, A., MacDonald, D., Avila, R., Calil, P. %D 2020 %J Journal of Geophysical Research : Oceans %N 1 %P e2019JC015338 %R doi:10.1029/2019JC015338 %T On the Role of Turbulent Mixing Produced by Vertical Shear Between the Brazil Current and the Intermediate Western Boundary Current %U https://doi.org/10.1029/2019JC015338 1 %X An intensification of the vertical shear is observed below the surface mixed layer at 21°S due to the mutually opposing flows of the Brazil Current and the Intermediate Western Boundary Current. The propensity to develop turbulence and mixing due to vertical shear over intense stabilizing density gradients is an important characteristic of such environments. For the first time, microscale measurements were made in the Brazil Current‐Intermediate Western Boundary Current system, providing direct quantitative values of the turbulent fluctuations. Peaks of relative strong dissipation rates of turbulent kinetic energy (O(10 urn:x-wiley:jgrc:media:jgrc23794:jgrc23794-math-0001) W/kg) were observed close to the base of the surface mixed layer. On the other hand, prominent peaks of turbulent kinetic energy dissipation rates of up to 2 orders of magnitude higher than the background were observed at deeper levels, where stratification begins to lose intensity. Analyzing such peaks, caused by intense vertical shear or weak stratification—and sometimes both—, allows a characterization of the local mixing processes and the role played by vertical exchanges of biogeochemical properties. Based on the estimated nitrate gradient and the vertical diffusivity, we show that turbulent mixing driven by vertical shear plays an important role in the supply of nitrate to the upper layer. %0 journal article %@ 0142-7873 %A Möller, K., St. John, M., Temming, A., Diekmann, R., Peters, J., Floeter, J., Sell, A., Herrmann, J., Gloe, D., Schmidt, J., Hinrichsen, H., Möllmann, C. %D 2020 %J Journal of Plankton Research %N 6 %P 702-713 %R doi:10.1093/plankt/fbaa044 %T Predation risk triggers copepod small-scale behavior in the Baltic Sea %U https://doi.org/10.1093/plankt/fbaa044 6 %X Predators not only have direct impact on biomass but also indirect, non-consumptive effects on the behavior their prey organisms. A characteristic response of zooplankton in aquatic ecosystems is predator avoidance by diel vertical migration (DVM), a behavior which is well studied on the population level. A wide range of behavioral diversity and plasticity has been observed both between- as well as within-species and, hence, investigating predator–prey interactions at the individual level seems therefore essential for a better understanding of zooplankton dynamics. Here we applied an underwater imaging instrument, the video plankton recorder (VPR), which allows the non-invasive investigation of individual, diel adaptive behavior of zooplankton in response to predators in the natural oceanic environment, providing a finely resolved and continuous documentation of the organisms’ vertical distribution. Combing observations of copepod individuals observed with the VPR and hydroacoustic estimates of predatory fish biomass, we here show (i) a small-scale DVM of ovigerous Pseudocalanus acuspes females in response to its main predators, (ii) in-situ observations of a direct short-term reaction of the prey to the arrival of the predator and (iii) in-situ evidence of pronounced individual variation in this adaptive behavior with potentially strong effects on individual performance and ecosystem functioning. %0 journal article %@ 0022-3670 %A McSweeney, J., Lerczak, J., Barth, J., Becherer, J., MacKinnon, J., Waterhouse, A., Colosi, J., MacMahan, J., Feddersen, F., Calatoni, J., Simpson, A., Celona, S., Haller, M., Terill, E. %D 2020 %J Journal of Physical Oceanography %N 10 %P 2965-2981 %R doi:10.1175/JPO-D-20-0090.1 %T Alongshore Variability of Shoaling Internal Bores on the Inner Shelf %U https://doi.org/10.1175/JPO-D-20-0090.1 10 %X Temperature and velocity measurements from 42 moorings were used to investigate the alongshore variability of nonlinear internal bores as they propagated across the central California inner shelf. Moorings were deployed September–October 2017 offshore of the Point Sal headland. Regional coverage was ~30 km alongshore and ~15 km across shore, spanning 9–100-m water depths. In addition to subtidal processes modulating regional stratification, internal bores generated complex spatiotemporal patterns of stratification variability. Internal bores were alongshore continuous on the order of tens of kilometers at the 50-m isobath, but the length scales of frontal continuity decreased to O(1 km) at the 25-m isobath. The depth-averaged, bandpass-filtered (from 3 min to 16 h) internal bore kinetic energy (¯¯¯¯¯¯¯¯¯KEIB) was found to be nonuniform along a bore front, even in the case of an alongshore-continuous bore. The pattern of along-bore ¯¯¯¯¯¯¯¯¯KEIB variability varied for each bore, but a 2-week average indicated that ¯¯¯¯¯¯¯¯¯KEIB was generally strongest around Point Sal. The stratification ahead of a bore influenced both the bore’s amplitude and cross-shore evolution. The data suggest that alongshore stratification gradients can cause a bore to evolve differently at various alongshore locations. Three potential bore fates were observed: 1) bores transiting intact to the 9-m isobath, 2) bores being overrun by faster, subsequent bores, leading to bore-merging events, and 3) bores disappearing when the upstream pycnocline was near or below middepth. Maps of hourly stratification at each mooring and the estimated position of sequential bores demonstrated that an individual internal bore can significantly impact the waveguide of the subsequent bore. %0 book part %@ %A Möller, K. %D 2020 %J Biodiversität im Meer und an Land. Vom Wert biologischer Vielfalt %P 158-161 %R doi:10.2312/eskp.2020.1.7.3 %T Neue Einblicke durch Plankton-Observatorien %U https://doi.org/10.2312/eskp.2020.1.7.3 %X Am Anfang der Nahrungskette im Meer steht das Plankton. Plankton zeichnet sich durch eine ausgesprochen breite Artenvielfalt aus. Mittels neuer Unterwasser-Plankton-Observatorien soll die Vielfalt des Planktons besser erfasst werden. So können auch die Veränderungen der Biodiversität im Plankton erkannt werden, die im Zusammenhang mit dem Klimawandel auftreten. ■ Plankton ist die Basis der Ökosysteme des Meeres. ■ Durch den Klimawandel ändern sich die Artenverteilung und -zusammensetzung im Meer. ■ Mehr Wissen über die Zusammenhänge ist eine wichtige Voraussetzung für das nachhaltige Management mariner Ökosysteme. ■ Die Verteilung des Planktons kann mittels neuer bildgebender Verfahren erfasst werden. ■ Vor Helgoland wird ein neues Unterwasser-Zooplankton-Observatorium (ZooObs) eingesetzt. %0 journal article %@ 0094-8276 %A Carpenter, J., Rodrigues, A., Schultze, L., Merckelbach, L., Baschek, B., Umlauf, L. %D 2020 %J Geophysical Research Letters %N 23 %P e2020GL090365 %R doi:10.1029/2020GL090365 %T Shear Instability and Turbulence Within a Submesoscale Front Following a Storm %U https://doi.org/10.1029/2020GL090365 23 %X Narrow baroclinic fronts are observed in the surface mixed layer (SML) of the Baltic Sea following an autumn storm. The fronts are subjected to hydrodynamic instabilities that lead to submesoscale and turbulent motions while restratifying the SML. We describe observations from an ocean glider that combines currents, stratification, and turbulence microstructure in a high horizontal resolution (150–300 m) to analyze such fronts. The observations show that SML turbulence is strongly modulated by frontal activity, acting as both source and sink for turbulent kinetic energy. In particular, a direct route to turbulent dissipation within the front is linked to shear instability caused by elevated nongeostrophic shear. The turbulent dissipation of frontal kinetic energy is large enough that it could be a significant influence in the evolution of the front and demonstrates that small‐scale turbulence can act as a significant sink of submesoscale kinetic energy. %0 journal article %@ 2169-9275 %A Savelyev, I., Buckley, M., Haus, B. %D 2020 %J Journal of Geophysical Research : Oceans %N 1 %P e2019JC015573 %R doi:10.1029/2019JC015573 %T The Impact of Nonbreaking Waves on Wind‐Driven Ocean Surface Turbulence %U https://doi.org/10.1029/2019JC015573 1 %X A comprehensive study on the properties of upper ocean turbulence and its response to a variety of wind and wave forcing conditions was conducted at the Surge Structure Atmosphere INteraction (SUSTAIN) facility, University of Miami, RSMAS. The dimensions of SUSTAIN wind‐wave‐current tunnel are 18 m long, 6 m wide, and 2 m high, uniquely allowing for freely forming turbulence unconstrained by side walls. The grid of input parameters covered a range of wave steepness (ak : 0–0.27) within each investigated wind speed (U 10: 2–20 m/s), allowing for the isolation of wave effects on the turbulence driven by both wind and waves. The response of turbulence to each pair of wind‐wave parameters was measured in steady‐state conditions (after 20+ min of settling time) by a suite of nonintrusive turbulence visualization techniques, located at 10 m fetch. These included 3‐D visualization of water tracing dye entrainment by turbulence, underwater particle image velocimetry, and passive and active thermal imagery resolving surface skin temperature and velocity fluctuations. The resulting data set includes both qualitative 3‐D view of subsurface turbulent structures and precise quantitative turbulent kinetic energy (TKE) measurements mapped out in response to the grid of input parameters. In lower winds, TKE was found to grow substantially in response to increasing wave steepness, in line with the expected effect of increasing wave forcing. However, in higher winds the effect of increasing wave steepness on TKE was found to be negative. It is hypothesized to be due to the rise of airflow separation, effectively sheltering much of the water surface from turbulence production by wind friction. %0 report %@ 1866-3192 %A Bussmann, I., Brix, H., Esposito, M., Friedrich, M., Fischer, P. %D 2020 %J Berichte zur Polar- und Meeresforschung %R doi:10.2312/BzPM_0741_2020 %T The MOSES Sternfahrt Expeditions of the Research Vessels LITTORINA, LUDWIG PRANDTL, MYA II, UTHÖRN to the inner German Bight in 2019 %U https://doi.org/10.2312/BzPM_0741_2020 %X %0 online contribution %@ %A Eschenbach, C., Horstmann, J. %D 2020 %J Earth System Knowledge Platform [eskp.de] %R doi:10.48440/eskp.056 %T Windböen kurzfristig vorhersagen %U https://doi.org/10.48440/eskp.056 %X Windböen auf hoher See können für Segler aber auch für Versorgungshelikopter von Offshore-Anlagen zu einer echten Gefahr werden. Windkraftanlagen im Meer sind durch Böen besonderen Belastungen und Schadensrisiken ausgesetzt. Könnte man Böen kurzfristig vorhersagen, ließen sich die Rotorblätter schnell und gezielt aus der Böe drehen. Mit dem Einsatz von Radartechnik ist das Helmholtz-Zentrum Geesthacht einer besseren Vorhersage von Windböen nun einen großen Schritt näher gekommen. %0 journal article %@ 1726-4170 %A Delaigue, L., Thomas, H., Mucci, A. %D 2020 %J Biogeosciences %N 2 %P 547-566 %R doi:10.5194/bg-17-547-2020 %T Spatial variations in CO2 fluxes in the Saguenay Fjord (Quebec, Canada) and results of a water mixing model %U https://doi.org/10.5194/bg-17-547-2020 2 %X The Saguenay Fjord is a major tributary of the St. Lawrence Estuary and is strongly stratified. A 6–8 m wedge of brackish water typically overlies up to 270 m of seawater. Relative to the St. Lawrence River, the surface waters of the Saguenay Fjord are less alkaline and host higher dissolved organic carbon (DOC) concentrations. In view of the latter, surface waters of the fjord are expected to be a net source of CO2 to the atmosphere, as they partly originate from the flushing of organic-rich soil porewaters. Nonetheless, the CO2 dynamics in the fjord are modulated with the rising tide by the intrusion, at the surface, of brackish water from the Upper St. Lawrence Estuary, as well as an overflow of mixed seawater over the shallow sill from the Lower St. Lawrence Estuary. Using geochemical and isotopic tracers, in combination with an optimization multiparameter algorithm (OMP), we determined the relative contribution of known source waters to the water column in the Saguenay Fjord, including waters that originate from the Lower St. Lawrence Estuary and replenish the fjord's deep basins. These results, when included in a conservative mixing model and compared to field measurements, serve to identify the dominant factors, other than physical mixing, such as biological activity (photosynthesis, respiration) and gas exchange at the air–water interface, that impact the water properties (e.g., pH, pCO2) of the fjord. Results indicate that the fjord's surface waters are a net source of CO2 to the atmosphere during periods of high freshwater discharge (e.g., spring freshet), whereas they serve as a net sink of atmospheric CO2 when their practical salinity exceeds ∼5–10. %0 journal article %@ 0022-3670 %A Becherer, J., Moum, J., Colosi, J., Lerczak, J., McSweeney, J. %D 2020 %J Journal of Physical Oceanography %N 8 %P 2373-2391 %R doi:10.1175/JPO-D-19-0178.1 %T Turbulence Asymmetries in Bottom Boundary Layer Velocity Pulses Associated with Onshore-Propagating Nonlinear Internal Waves %U https://doi.org/10.1175/JPO-D-19-0178.1 8 %X The inner shelf is a region inshore of that part of the shelf that roughly obeys Ekman dynamics and offshore of the surf zone. Importantly, this is where surface and bottom boundary layers are in close proximity, overlap, and interact. The internal tide carries a substantial amount of energy into the inner shelf region were it eventually dissipates and contributes to mixing. A part of this energy transformation is due to a complex interaction with the bottom, where distinctions between nonlinear internal waves of depression and elevation are blurred, indeed, where polarity reversals of incoming waves take place. From an intensive set of measurements over the inner shelf off central California, we identify salient differences between onshore pulses from waves with properties of elevation waves and offshore pulses from shallowing depression waves. While the velocity structures and amplitudes of on/offshore pulses 1 m above the seafloor are not detectably different, onshore pulses are both more energetically turbulent and carry more sediments than offshore pulses. Their turbulence is also oppositely skewed: onshore pulses slightly to the leading edges, offshore pulses to the trailing edges of the pulses. We consider in turn three independent mechanisms that may contribute to the observed asymmetry: propagation in adverse pressure gradients and the resultant inflection point instability, residence time of a fluid parcel in the pulse, and turbulence suppression by stratification. The first mechanism may largely explain higher turbulence in the trailing edge of offshore pulses. The extended residence time may be responsible for the high and more uniform turbulence distribution across onshore compared to offshore pulses. Stratification does not play a leading role in turbulence modification inside of the pulses 1 m above the bed. %0 journal article %@ 0035-9009 %A Heifetz, E., Maor, R., Guha, A. %D 2020 %J Quarterly Journal of the Royal Meteorological Society %P 1056-1064 %R doi:10.1002/qj.3719 %T On the opposing roles of the Boussinesq and non‐Boussinesq baroclinic torques in surface gravity wave propagation %U https://doi.org/10.1002/qj.3719 %X Here we suggest an alternative understanding of the surface gravity wave propagation mechanism based on the baroclinic torque, which operates to translate the interfacial vorticity anomalies at the air–water interface. We demonstrate how the non‐Boussinesq term of the baroclinic torque acts against the Boussinesq one to hinder wave propagation. By standard vorticity inversion and mirror imaging, we then show how the existence of the bottom boundary affects the two types of torque. Since the opposing non‐Boussinesq torque results solely from the mirror image, it vanishes in the deep‐water limit and its magnitude is half of the Boussinesq torque in the shallow‐water limit. This reveals that the Boussinesq approximation is valid in the deep‐water limit, even though the density contrast between air and water is large. The mechanistic roles played by the Boussinesq and non‐Boussinesq parts of the baroclinic torque remain obscured in the standard derivation where the time‐dependent Bernoulli equation is implemented instead of the interfacial vorticity equation. Finally, we note on passing that the Virial theorem for surface gravity waves can be obtained solely from considerations of the dynamics at the air–water interface. %0 journal article %@ 2468-0672 %A Thomsen, S., Hansen, M., Lillethorup, J., Tirsgaard, F., Flytkjaer, A., Melvad, C., Rysgaard, S., Carlson, D. %D 2020 %J HardwareX %P e00101 %R doi:10.1016/j.ohx.2020.e00101 %T An affordable and miniature ice coring drill for rapid acquisition of small iceberg samples %U https://doi.org/10.1016/j.ohx.2020.e00101 %X Icebergs account for approximately half of the freshwater flux from the Greenland Ice Sheet and they can impact marine ecosystems by releasing nutrients and sediments into the ocean as they drift and melt. Parameterizing iceberg fluxes of nutrients and sediments to fjord and ocean waters remains a difficult task due to the complexity of ice-ocean interactions and is complicated by a lack of observations. Acquiring iceberg samples can be difficult and dangerous, as icebergs can break apart and roll without warning. Here we present open source design files for a small, lightweight ice coring drill that can be reproduced using modern computer numerical control (CNC) machining and 3D printing technology. This ice core drill can rapidly acquire small ice samples from icebergs and bergy bits using a standard commercial, off-the-shelf battery-operated hand drill. Design files and a recent field expedition to Northwest Greenland are described. Ice core collection required only 30 s, thereby minimizing risks to scientists. %0 journal article %@ 0034-4257 %A Chernyshov, P., Vrecica, T., Streßer, M., Carrasco, R., Toledo, Y. %D 2020 %J Remote Sensing of Environment %P 111688 %R doi:10.1016/j.rse.2020.111688 %T Rapid wavelet-based bathymetry inversion method for nearshore X-band radars %U https://doi.org/10.1016/j.rse.2020.111688 %X In order to verify the proposed method, 2D simulations of wave shoaling and refraction were performed for different sea conditions and over several bottom topographies. A radar image model including tilt and shadowing modulations together with speckle noise was applied to the simulated surface elevations to provide synthetic radar images. The method's ability to reconstruct the original bathymetry is shown to be robust in intermediate to shallow water depths (kph < 1) for all cases. The method was also applied to real data acquired in Sylt island (Germany). A comparison between a bathymetric survey held prior to a storm and a radar reconstructed one during the storm shows very good agreement. These results reassure the high capability of this new method to be used in operational settings. %0 journal article %@ 2378-2242 %A Schultze, L., Merckelbach, L., Carpenter, J. %D 2020 %J Limnology and oceanography letters %N 3 %P 264-270 %R doi:10.1002/lol2.10139 %T Storm‐induced turbulence alters shelf sea vertical fluxes %U https://doi.org/10.1002/lol2.10139 3 %X Storms are infrequent, intense, physical forcing events that represent a potentially significant driver of ocean ecosystems. The objective of this study was to assess changes in water column structure and turbulent fluxes caused by storms using an autonomous underwater glider, as well as the chlorophyll a (Chl a ) response to the altered physical environment. The glider was able to measure throughout the complete life cycle of Storm Bertha as it passed over the North Sea in August 2014, from its arrival to dissipation. Storm Bertha triggered rapid mixing of the thermocline through shear instability, increasing vertical fluxes by nearly an order of magnitude, and promoting increases in surface layer Chl a . The results demonstrate that storms represent a significant fraction of seasonal vertical turbulent fluxes, with potentially important consequences for biological production in shelf seas. %0 dataset %@ %A Carrasco, R., Horstmann, J., Körtzinger, A. %D 2020 %J Pangaea %R doi:10.1594/PANGAEA.918612 %T Surface drifter data from Meteor cruise M160 %U https://doi.org/10.1594/PANGAEA.918612 %X Surface current drifters were deployed east of Brava island (Cape Verde archipelago, Atlantic ocean) from the RV Meteor during the cruise M160, which took place between 22. November and 20. December 2019. The drifters were deployed in 3 clusters with 3 drifters per cluster. The utilized drifters are the MD03i from Albatros Marine Technologies, Spain. They have a cylinder shape with a 10 cm diameter and 32 cm length. About 8 cm protrude from the water surface and a drogue of both 50 cm length and diameter is attached to each drifter 50 cm below the sea surface so that difter represent currents in the upper 1 m surface layer. The drifter obtains the GPS position and transmits it via the satellite communication system Iridium to the vessel. The overall ratio of drag area inside to drag area outside the water is 33.2. %0 online contribution %@ %A Eschenbach, C. %D 2020 %J Earth System Knowledge Platform [eskp.de] %R doi:10.2312/eskp.053 %T Alkalinität: die unterschätzte Köchin in der „Klimaküche Ozean“ %U https://doi.org/10.2312/eskp.053 %X Die Fähigkeit der Ozeane, atmosphärisches CO2 aufzunehmen, ist essentiell für die Klimaregulation des Erdsystems. Die sogenannte Alkalinität, als Maß für diese Aufnahmekapazität, spielt eine große Rolle in der „Klimaküche Ozean“. Sie hängt vor allem von Gehalt an Karbonaten im Meerwasser ab und ist Ergebnis der Wechselwirkungen verschiedener Komponenten des Kohlenstoff- und Nährstoffhaushalts. Die Frage ist letztlich auch, wie stark der Klimawandel das natürliche Alkalinitäts-Gleichgewicht stören kann. %0 journal article %@ 1616-7341 %A Langa, A., Calil, P. %D 2020 %J Ocean Dynamics %P 95-114 %R doi:10.1007/s10236-019-01311-0 %T On the role of physical processes on the surface chlorophyll variability in the Northern Mozambique Channel %U https://doi.org/10.1007/s10236-019-01311-0 %X In the Indian Ocean regions under the influence of monsoons, two phytoplankton blooms characterize the seasonal cycle of surface chlorophyll, one during summer, and the other during winter. In the Northern Mozambique Channel, however, where the wind regime is an extension of the northern Indian Ocean monsoons, the annual cycle of chlorophyll concentrations is characterized by a single winter bloom. Wind stress and surface net heat flux modulate the seasonal cycle of the mixed layer depth with impacts on the surface chlorophyll. In order to evaluate the importance of these forcing fields on the seasonality of the mixed layer depth, and consequently, the surface chlorophyll variability, we used a suite of physical-biogeochemical model sensitivity experiments. Our results show that the seasonal cycle of surface chlorophyll is primarily modulated by the net heat flux while the wind field controls the amplitude. The winter bloom is triggered by negative surface heat fluxes, where cooling at the surface induces mixing and entrainment of nutrients at the base of the nutricline and light is not limiting. Winds enhance the winter bloom by uplifting additional nutrients and diluting subsurface chlorophyll into the surface layer. In the summertime, weaker wind stress and positive heat flux inhibit vertical mixing. As a consequence, the surface layer is depleted in nutrients and a deep chlorophyll maximum is formed. Analysis of top-down control on phytoplankton biomass reveals that zooplankton abundance increases in a near-linear proportion with phytoplankton biomass despite the deepening of the mixed layer depth. This suggests that the phytoplankton stock in the Northern Mozambique Channel is also controlled by grazing, given that zooplankton biomass is not directly affected by the deepening of the mixed layer during wintertime. %0 journal article %@ 2311-5521 %A Lodise, J., Özgökmen, T., Gonçalves, R., Iskandarani, M., Lund, B., Horstmann, J., Poulain, P., Klymak, J., Ryan, E., Guigand, C. %D 2020 %J Fluids %N 3 %P 159 %R doi:10.3390/fluids5030159 %T Investigating the Formation of Submesoscale Structures along Mesoscale Fronts and Estimating Kinematic Quantities Using Lagrangian Drifters %U https://doi.org/10.3390/fluids5030159 3 %X Much of the vertical transport near the surface of the ocean, which plays a critical role in the transport of dissolved nutrients and gases, is thought to be associated with ageostrophic submesoscale phenomena. Vertical velocities are challenging not only to model accurately, but also to measure because of how difficult they are to locate in the surface waters of the ocean. Using unique massive drifter releases during the Lagrangian Submesoscale Experiment (LASER) campaign in the Gulf of Mexico and the Coherent Lagrangian Pathways from the Surface Ocean to the Interior (CALYPSO) experiment in the Mediterranean Sea, we investigate the generation of submesoscale structures along two different mesoscale fronts. We use a novel method to project Lagrangian trajectories to Eulerian velocity fields, in order to calculate horizontal velocity gradients at the surface, which are used as a proxy for vertical transport. The velocity reconstruction uses a squared-exponential covariance function, which characterizes velocity correlations in horizontal space and time, and determines the scales of variation using the data itself. SST and towed CTD measurements support the findings revealed by the drifter data. Due to the production of a submesoscale instability eddy in the Gulf of Mexico, convergence magnitudes of up to ∼20 times the planetary vorticity, f, are observed, the value of which is almost 3 times larger than that found in the mesoscale dominated Western Mediterranean Sea. %0 journal article %@ 1994-0416 %A Hopwood, M., Carroll, D., Dunse, T., Hodson, A., Holding, J., Iriarte, J., Ribeiro, S., Achterberg, E., Cantoni, C., Carlson, D., Chierici, M., Clarke, J., Cozzi, S., Fransson, A., Juul-Pedersen, T., Winding, M., Meire, L. %D 2020 %J The Cryosphere %N 4 %P 1347-1383 %R doi:10.5194/tc-14-1347-2020 %T Review article: How does glacier discharge affect marine biogeochemistry and primary production in the Arctic? %U https://doi.org/10.5194/tc-14-1347-2020 4 %X Freshwater discharge from glaciers is increasing across the Arctic in response to anthropogenic climate change, which raises questions about the potential downstream effects in the marine environment. Whilst a combination of long-term monitoring programmes and intensive Arctic field campaigns have improved our knowledge of glacier–ocean interactions in recent years, especially with respect to fjord/ocean circulation, there are extensive knowledge gaps concerning how glaciers affect marine biogeochemistry and productivity. Following two cross-cutting disciplinary International Arctic Science Committee (IASC) workshops addressing the importance of glaciers for the marine ecosystem, here we review the state of the art concerning how freshwater discharge affects the marine environment with a specific focus on marine biogeochemistry and biological productivity. Using a series of Arctic case studies (Nuup Kangerlua/Godthåbsfjord, Kongsfjorden, Kangerluarsuup Sermia/Bowdoin Fjord, Young Sound and Sermilik Fjord), the interconnected effects of freshwater discharge on fjord–shelf exchange, nutrient availability, the carbonate system, the carbon cycle and the microbial food web are investigated. Key findings are that whether the effect of glacier discharge on marine primary production is positive or negative is highly dependent on a combination of factors. These include glacier type (marine- or land-terminating), fjord–glacier geometry and the limiting resource(s) for phytoplankton growth in a specific spatio-temporal region (light, macronutrients or micronutrients). Arctic glacier fjords therefore often exhibit distinct discharge–productivity relationships, and multiple case-studies must be considered in order to understand the net effects of glacier discharge on Arctic marine ecosystems. %0 journal article %@ 0022-1120 %A Yousefi, K., Veron, F., Buckley, M. %D 2020 %J Journal of Fluid Mechanics %P A15 %R doi:10.1017/jfm.2020.276 %T Momentum flux measurements in the airflow over wind-generated surface waves %U https://doi.org/10.1017/jfm.2020.276 %X The air–sea momentum exchanges in the presence of surface waves play an integral role in coupling the atmosphere and the ocean. In the current study, we present a detailed laboratory investigation of the momentum fluxes over wind-generated waves. Experiments were performed in the large wind-wave facility at the Air–Sea Interaction Laboratory of the University of Delaware. Airflow velocity measurements were acquired above wind waves using a combination of particle image velocimetry and laser-induced fluorescence techniques. The momentum budget is examined using a wave-following orthogonal curvilinear coordinate system. In the wave boundary layer, the phase-averaged turbulent stress is intense (weak) and positive downwind (upwind) of the crests. The wave-induced stress is also positive on the windward and leeward sides of wave crests but with asymmetric intensities. These regions of positive wave stress are intertwined with regions of negative wave stress just above wave crests and downwind of wave troughs. Likewise, at the interface, the viscous stress exhibits along-wave phase-locked variations with maxima upwind of the wave crests. As a general trend, the mean profiles of the wave-induced stress decrease to a negative minimum from a near-zero value far from the surface and then increase rapidly to a positive value near the interface where the turbulent stress is reduced. Far away from the surface, however, the turbulent stress is nearly equal to the total stress. Very close to the surface, in the viscous sublayer, the wave and turbulent stresses vanish, and therefore the stress is supported by the viscosity. %0 journal article %@ 1726-4170 %A Schwichtenberg, F., Pätsch, J., Böttcher, M., Thomas, H., Winde, V., Emeis, K. %D 2020 %J Biogeosciences %N 16 %P 4223-4245 %R doi:10.5194/bg-17-4223-2020 %T The impact of intertidal areas on the carbonate system of the southern North Sea %U https://doi.org/10.5194/bg-17-4223-2020 16 %X The coastal ocean is strongly affected by ocean acidification because of its shallow water depths, low volume, and the closeness to terrestrial dynamics. Earlier observations of dissolved inorganic carbon (DIC) and total alkalinity (TA) in the southern part of the North Sea, a northwest European shelf sea, revealed lower acidification effects than expected. It has been assumed that anaerobic degradation and subsequent TA release in the adjacent back-barrier tidal areas (Wadden Sea) in summertime is responsible for this phenomenon. In this study the exchange rates of TA and DIC between the Wadden Sea tidal basins and the North Sea and the consequences for the carbonate system in the German Bight are estimated using a 3D ecosystem model. The aim of this study is to differentiate the various sources contributing to observed high summer TA in the southern North Sea. Measured TA and DIC in the Wadden Sea are considered as model boundary conditions. This procedure acknowledges the dynamic behaviour of the Wadden Sea as an area of effective production and decomposition of organic material. According to the modelling results, 39 Gmol TA yr−1 were exported from the Wadden Sea into the North Sea, which is less than a previous estimate but within a comparable range. The interannual variabilities in TA and DIC, mainly driven by hydrodynamic conditions, were examined for the years 2001–2009. Dynamics in the carbonate system are found to be related to specific weather conditions. The results suggest that the Wadden Sea is an important driver for the carbonate system in the southern North Sea. On average 41 % of TA inventory changes in the German Bight were caused by riverine input, 37 % by net transport from adjacent North Sea sectors, 16 % by Wadden Sea export, and 6 % were caused by internal net production of TA. The dominant role of river input for the TA inventory disappears when focusing on TA concentration changes due to the corresponding freshwater fluxes diluting the marine TA concentrations. The ratio of exported TA versus DIC reflects the dominant underlying biogeochemical processes in the Wadden Sea. Whereas aerobic degradation of organic matter played a key role in the North Frisian Wadden Sea during all seasons of the year, anaerobic degradation of organic matter dominated in the East Frisian Wadden Sea. Despite the scarcity of high-resolution field data, it is shown that anaerobic degradation in the Wadden Sea is one of the main contributors of elevated summer TA values in the southern North Sea. %0 journal article %@ 1364-503X %A Kostakis, I., Röttgers, R., Orkney, A., Bouman, H., Porter, M., Cottier, F., Berge, J., McKee, D. %D 2020 %J Philosophical Transactions of the Royal Society. Series A, Mathematical, Physical and Engineering Sciences %N 2181 %P 20190367 %R doi:10.1098/rsta.2019.0367 %T Development of a bio-optical model for the Barents Sea to quantitatively link glider and satellite observations %U https://doi.org/10.1098/rsta.2019.0367 2181 %X A bio-optical model for the Barents Sea is determined from a set of in situ observations of inherent optical properties (IOPs) and associated biogeochemical analyses. The bio-optical model provides a pathway to convert commonly measured parameters from glider-borne sensors (CTD, optical triplet sensor—chlorophyll and CDOM fluorescence, backscattering coefficients) to bulk spectral IOPs (absorption, attenuation and backscattering). IOPs derived from glider observations are subsequently used to estimate remote sensing reflectance spectra that compare well with coincident satellite observations, providing independent validation of the general applicability of the bio-optical model. Various challenges in the generation of a robust bio-optical model involving dealing with partial and limited quantity datasets and the interpretation of data from the optical triplet sensor are discussed. Establishing this quantitative link between glider-borne and satellite-borne data sources is an important step in integrating these data streams and has wide applicability for current and future integrated autonomous observation systems. %0 journal article %@ 2169-9275 %A Berta, M., Griffa, A., Haza, A., Horstmann, J., Huntley, H., Ibrahim, R., Lund, B., Özgökmen, T., Poje, A. %D 2020 %J Journal of Geophysical Research : Oceans %N 10 %P e2020JC016085 %R doi:10.1029/2020JC016085 %T Submesoscale kinematic properties in summer and winter surface flows in the Northern Gulf of Mexico %U https://doi.org/10.1029/2020JC016085 10 %X Statistical properties of near‐surface horizontal velocity gradients are obtained from four drifter experiments conducted in the Gulf Mexico during Summer 2012 and Winter 2016. The data density provided by the near‐simultaneous deployments of 90‐326 surface drifters in each allows direct, drifter‐based estimates of the scale dependence of velocity gradients at separation scales ranging from 200 m to 5 km. The robustness of these estimates, derived from uniquley sampled, nearly equilateral triplets, is confirmed by comparisons with estimates produced from larger drifter clusters, and with estimates based on concurrent Eulerian X‐band radar observations. The winter launches were deployed above a ~80 m deep mixed layer, one in a region with nearly homogeneous horizontal density structure, the other in a region of strong surface density gradients associated with filaments of fresh Mississippi River water. The summer launches occurred in a shallow (10m) mixed layer, one launched across a mesoscale frontal jet separating regions of horizontally homogeneous density and the other, similar to the corresponding winter launch, also in a region filamented by shallow lenses of cold, fresh water. Seasonal differences are observed, with larger velocity fluctuations and greater variance in divergence and vorticity, especially at the smallest scales, in winter. Differences between same‐season launches are, however, as large as seasonal differences. In both seasons, observations sampling regions directly impacted by fresh water fluxes show strongly skewed vorticity distributions, with cyclonic vorticity dominating strain. For the other launches, one in each season, strain dominated minimally skewed vorticity. %0 journal article %@ 2169-9275 %A Schultze, L., Merckelbach, L., Horstmann, J., Raasch, S., Carpenter, J. %D 2020 %J Journal of Geophysical Research : Oceans %N 8 %P e2019JC015858 %R doi:10.1029/2019JC015858 %T Increased Mixing and Turbulence in the Wake of Offshore Wind Farm Foundations %U https://doi.org/10.1029/2019JC015858 8 %X The addition of offshore wind farms (OWFs) to stratified regions of shelf seas poses an anthropogenic source of turbulence, in which the foundation structures remove power from the oceanic flow that is fed into turbulent mixing in the wake downstream. The loss of stratification within the wake of a single OWF structure is observed for the first time by means of field observations, which enable a qualitative characterization of the disturbed flow downstream. These results are complemented with high‐resolution large‐eddy simulations of four different stratification strengths that allow for a quantification of turbulence and mixing quantities in the wake of a foundation structure. The turbulent wake of a structure is narrow and highly energetic within the first 100 m, with the dissipation of turbulent kinetic energy well above background levels downstream of the structure. A single monopile is responsible for 7–10% additional mixing to that of the bottom mixed layer, whereby approximately 10% of the turbulent kinetic energy generated by the structure is used in mixing. Although the effect of a single turbine on stratification is relatively low, large‐scale OWFs could significantly affect the vertical structure of a weakly stratified water column. Further, rough estimates show that the rate of formation of stratification in the study area is of the same order of magnitude as the additional mixing promoted by the structures, thus OWFs could modify the stratification regime and water column dynamics on a seasonal scale, depending on local conditions and farm geometries. %0 journal article %@ 0892-0753 %A Maradino, C., van Doorn, E., McDonald, N., Johnson, M., Acma, B., Breviere, E., Campen, H., Carou, S., Cocco, E., Endres, S., Hilmi, N., Hopkins, F., Liss, P., Maes, F., Martensson, M., Oeffner, J., Oloyede, M., Peters, A., Quack, B., Singh, P., Thomas, H. %D 2020 %J Coastal Management %N 4 %P 238-256 %R doi:10.1080/08920753.2020.1773208 %T From Monodisciplinary via Multidisciplinary to an Interdisciplinary Approach Investigating Air-Sea Interactions – a SOLAS Initiative %U https://doi.org/10.1080/08920753.2020.1773208 4 %X Understanding the physical and biogeochemical interactions and feedbacks between the ocean and atmosphere is a vital component of environmental and Earth system research. The ability to predict and respond to future environmental change relies on a detailed understanding of these processes. The Surface Ocean-Lower Atmosphere Study (SOLAS) is an international research platform that focuses on the study of ocean-atmosphere interactions, for which Future Earth is a sponsor. SOLAS instigated a collaborative initiative process to connect efforts in the natural and social sciences related to these processes, as a contribution to the emerging Future Earth Ocean Knowledge-Action Network (Ocean KAN). This is imperative because many of the recent changes in the Earth system are anthropogenic. An understanding of adaptation and counteracting measures requires an alliance of scientists from both domains to bridge the gap between science and policy. To this end, three SOLAS research areas were targeted for a case study to determine a more effective method of interdisciplinary research: valuing carbon and the ocean’s role; air-sea interactions, policy and stewardship; and, air-sea interactions and the shipping industry. %0 journal article %@ 1726-4170 %A Mears, C., Thomas, H., Henderson, P., Charette, M., MacIntyre, H., Dehairs, F., Monnin, C., Mucci, A. %D 2020 %J Biogeosciences %N 20 %P 4937-4959 %R doi:10.5194/bg-17-4937-2020 %T Using 226Ra and 228Ra isotopes to distinguish water mass distribution in the Canadian Arctic Archipelago %U https://doi.org/10.5194/bg-17-4937-2020 20 %X As a shelf dominated basin, the Arctic Ocean and its biogeochemistry are heavily influenced by continental and riverine sources. Radium isotopes (226Ra, 228Ra, 224Ra, 223Ra), are transferred from the sediments to seawater, making them ideal tracers of sediment-water exchange processes and ocean mixing. 226Ra and 228Ra are the two longer-lived isotopes of the Radium Quartet (226Ra, t1/2 = 1600 y and 228Ra, t1/2 = 5.8 y). Because of their long half-lives they can provide insight into the water mass compositions, distribution patterns, as well as mixing processes and the associated timescales throughout the Canadian Arctic Archipelago (CAA). The wide range of 226Ra, 228Ra, and of the 228Ra / 226Ra ratio, measured in water samples collected during the 2015 GEOTRACES cruise, complemented by additional chemical tracers (dissolved inorganic carbon (DIC), total alkalinity (AT), barium (Ba), and the stable oxygen isotope composition of water (δ18O)) highlight the dominant biogeochemical, hydrographic and bathymetric features of the CAA. Bathymetric features, such as the continental shelf and shallow coastal sills, are critical in modulating circulation patterns within the CAA, including the bulk flow of Pacific waters and the inhibited eastward flow of denser Atlantic waters through the CAA. Using a Principal Component Analysis, we unravel the dominant mechanisms and the apparent water mass end-members that shape the tracer distributions. We identify two distinct water masses located above and below the upper halocline layer throughout the CAA, as well as distinctly differentiate surface waters in the eastern and western CAA. Furthermore, we identify water exchange across 80° W, inferring a draw of Atlantic water, originating from Baffin Bay, into the CAA. In other words, this implies the presence of an Atlantic water U-turn located at Barrow Strait, where the same water mass is seen along the northernmost edge at 80° W as well as along south-easternmost confines of Lancaster Sound. Overall, this study provides a stepping stone for future research initiatives within the Canadian Arctic Archipelago, revealing how quantifying disparities in radioactive isotopes can provide valuable information on the potential effects of climate change within vulnerable areas such as the CAA. %0 journal article %@ 1726-4170 %A Beaupré-Laperrière, A., Mucci, A., Thomas, H. %D 2020 %J Biogeosciences %N 14 %P 3923-3942 %R doi:10.5194/bg-17-3923-2020 %T The recent state and variability of the carbonate system of the Canadian Arctic Archipelago and adjacent basins in the context of ocean acidification %U https://doi.org/10.5194/bg-17-3923-2020 14 %X Ocean acidification driven by the uptake of anthropogenic CO2 by the surface oceans constitutes a potential threat to the health of marine ecosystems around the globe. The Arctic Ocean is particularly vulnerable to acidification and thus is an ideal region to study the progression and effects of acidification before they become globally widespread. The appearance of undersaturated surface waters with respect to the carbonate mineral aragonite (ΩA<1), an important threshold beyond which the calcification and growth of some marine organisms might be hindered, has recently been documented in the Canada Basin and adjacent Canadian Arctic Archipelago (CAA), a dynamic region with an inherently strong variability in biogeochemical processes. Nonetheless, few of these observations were made in the last 5 years and the spatial coverage in the latter region is poor. We use a dataset of carbonate system parameters measured in the CAA and its adjacent basins (Canada Basin and Baffin Bay) from 2003 to 2016 to describe the recent state of these parameters across the Canadian Arctic and investigate the amplitude and sources of the system's variability over more than a decade. Our findings reveal that, in the summers of 2014 to 2016, the ocean surface across our study area served as a net CO2 sink and was partly undersaturated with respect to aragonite in the Canada Basin and the Queen Maud Gulf, the latter region exhibiting undersaturation over its entire water column at some locations. We estimate, using measurements made across several years, that approximately a third of the interannual variability in surface dissolved inorganic carbon (DIC) concentrations in the CAA results from fluctuations in biological activity. In consideration of the system's variability resulting from these fluctuations, we derive times of emergence of the anthropogenic ocean acidification signal for carbonate system parameters in the study area. %0 journal article %@ 1755-098X %A Merckelbach, L., Borges, L. %D 2020 %J Molecular Ecology Resources %N 6 %P 1761-1768 %R doi:10.1111/1755-0998.13222 %T Make every species count: fastachar software for rapid determination of molecular diagnostic characters to describe species %U https://doi.org/10.1111/1755-0998.13222 6 %X Only a fraction of species found so far has been described, particularly cryptic species uncovered by molecular data. The latter might require the use of molecular data for its diagnosis, but it is important to make use of the diagnostic content of the molecular data itself. The molecular character‐based model provides discrete molecular diagnostic characters within DNA sequences that can be used in species descriptions fulfilling the requirement of most codes of nomenclature for a character‐based description of species. Here, we introduce fastachar, a software developed to extract molecular diagnostic characters from one or several taxonomically informative DNA markers of a selected taxon compared with those of other taxa in a single step. The input data consist of a single file with aligned sequences in the fasta format, which can be created using alignment software such as mega or geneious. fastachar is an easy‐to‐use software with a graphical interface. Thus, the software does not require the user to have any knowledge of the underlying programming environment (Python). We hope this software, based on the method proposed by Jörger and Schrödl (Frontiers in Zoology, 10, 59, 2013) to describe cryptic species, will encourage researchers to take the final step in taxonomy: the formal description of species. We propose the use of this method and fastachar also for the inclusion of molecular data in the description of any species. fastachar is released as open‐source software under GNU General Public License V3 and is freely available for all major operating systems from https://github.com/smerckel/FastaChar. %0 journal article %@ 1070-6631 %A Heifetz, E., Guha, A., Carpenter, J. %D 2020 %J Physics of Fluids %N 7 %P 074106 %R doi:10.1063/5.0011351 %T Wave interactions in neutrally stable shear layers: Regular and singular modes, and non-modal growth %U https://doi.org/10.1063/5.0011351 7 %X A recent letter [J. R. Carpenter and A. Guha, “Instability of a smooth shear layer through wave interactions,” Phys. Fluids 31, 081701 (2019)] compared the neutral modes of a smooth two-dimensional shear profile without an inflection point to the modes of its corresponding piecewise-linear profile. The regular mode in the smooth profile was identified as the one least sensitive to the numerical resolution, while the singular modes displayed high sensitivity. Here, we provide a physical interpretation using a wave interaction approach for understanding the structure and behavior of both the regular and singular modes. The regular modes are the interfacial Rossby waves located at the concentrated mean vorticity gradient of the shear profile. In contrast, the singular modes result from a one way phase-locking interaction between singular vorticity disturbances, passively advected by the mean flow at different levels of the profile, and the interfacial Rossby waves. We show that this one way interaction can also lead to a sustained non-modal growth of the interfacial Rossby waves that cannot be captured by standard eigenvalue analysis. %0 book part %@ %A Yousefi, K., Veron, F., Buckley, M. %D 2020 %J Recent Advances in the Study of Oceanic Whitecaps %P 77-94 %R doi:10.1007/978-3-030-36371-0_6 %T Measurements of Airside Shear- and Wave-Induced Viscous Stresses over Strongly Forced Wind Waves %U https://doi.org/10.1007/978-3-030-36371-0_6 %X Detailed knowledge of the airflow over the surface of the ocean is paramount to evaluate and predict air-sea fluxes. The flux of momentum is of particular interest because it involves phenomena over a large spectrum of length and temporal scales from aerodynamic drag in large storm systems, down to the wind-wave generation problem at sub-centimeter scales. At the smaller scales, while there is a body of theoretical and experimental work which suggests that the wind-wave generation process is linked to the instability of the coupled air-water surface flow, progress has been hindered by the difficulties associated with making reliable measurements or simulations near the air-water interface at scales at which viscosity plays a role. In this paper, we present recent measurements of the two-dimensional velocity field in the turbulent airflow above wind waves. Improvements in measuring techniques have allowed us to detect the viscous sublayer in the airflow near the interface and make direct measurements of the airside viscous tangential stress (analogous to those made by (Banner ML, Peirson WL, J Fluid Mech 364:115–145, 1998) on the water side). Furthermore, we were able to separate mean, turbulent, and wave-coherent motions, and this decomposition yielded wave-coherent flow measurements as well as wave-phase averages of several flow field variables. We present the relationship of the varying surface viscous stress with the dominant wave phase. Also, to the authors’ knowledge, we present the first measurements of airside wave-induced viscous stresses. We conclude that at low wind speed, surface viscous effects are substantial and likely need to be accounted for in the early stages of the wind-wave generation process. %0 journal article %@ 2296-7745 %A D'Asaro, E., Carlson, D., Chamecki, M., Harcourt, R., Haus, B., Fox-Kemper, B., Molemaker, M., Poje, A., Yang, D. %D 2020 %J Frontiers in Marine Science %P 349 %R doi:10.3389/fmars.2020.00349 %T Advances in Observing and Understanding Small-Scale Open Ocean Circulation During the Gulf of Mexico Research Initiative Era %U https://doi.org/10.3389/fmars.2020.00349 %X Predicting the distribution of oil, buoyant plastics, flotsam, and marine organisms near the ocean surface remains a fundamental problem of practical importance. This manuscript synthesizes progress in this area during the time of the Gulf of Mexico Research Initiative (GoMRI; 2012–2019), with an emphasis on the accumulation of floating material into highly concentrated streaks on horizontal scales of meters to 10's of kilometers. Prior to the GoMRI period, two new paradigms emerged: the importance of submesoscale frontal dynamics on the larger scales and of surface-wave-driven Langmuir turbulence on the smaller scales, with a broad transition occurring near 100 m. Rapid progress resulted from the combination of high resolution numerical modeling tools, mostly developed before GoMRI, and new observational techniques developed during GoMRI. Massive deployments of inexpensive and biodegradable satellite-tracked surface drifters combined with aerial tracking of oil surrogates (drift cards) enabled simultaneous observations of surface ocean velocities and dispersion over scales of 10 m to 10's of kilometers. Surface current maps produced by ship-mounted radar and aerial optical remote sensing systems, combined with traditional oceanographic tools, enabled a set of coordinated measurement programs that supported and expanded the new paradigms. Submesoscale fronts caused floating material to both accumulate at fronts and to disperse as they evolved, leading to higher local concentrations, but increased overall dispersion. Analyses confirmed the distinct submesoscale dynamics of this process and the complexity of the resulting fields. Existing tools could be developed into predictive models of submesoscale statistics, but prediction of individual submesoscale features will likely remain limited by data. Away from fronts, measured rates of accumulation of material in and beneath surface windrows was found to be consistent with Langmuir turbulence, but highly dependent on the rise rate of the material and thus, for oil, on the droplet size. Models of this process were developed and tested and could be further developed into predictive tools. Both the submesoscale and Langmuir processes are sensitive to coupling with surface waves and air-sea flux processes. This sensitivity is a promising area for future studies. %0 journal article %@ 1424-8220 %A Sticklus, J., Hoeher, P., Hieronymi, M. %D 2020 %J Sensors %N 18 %P 5200 %R doi:10.3390/s20185200 %T Experimental Characterization of Single-Color Power LEDs Used as Photodetectors %U https://doi.org/10.3390/s20185200 18 %X Semiconductor-based light emitting diodes can be used for photon emission as well as for detection of photons. In this paper, we present a fair comparison between off-the-shelf power Light emitting diodes (LEDs) and a silicon photodetector with respect to their spectral, temporal, and spatial properties. The examined LED series features unexpected good sensitivity and distinct optical bandpass characteristic suitable for daylight filtering or color selectivity. Primary application is short range optical underwater communication, but results are generally applicable. %0 journal article %@ 1726-4170 %A Kerimoglu, O., Voynova, Y., Chegini, F., Brix, H., Callies, U., Hofmeister, R., Klingbeil, K., Schrum, C., van Beusekom, J. %D 2020 %J Biogeosciences %N 20 %P 5097-5127 %R doi:10.5194/bg-17-5097-2020 %T Interactive impacts of meteorological and hydrological conditions on the physical and biogeochemical structure of a coastal system %U https://doi.org/10.5194/bg-17-5097-2020 20 %X The German Bight was exposed to record high riverine discharges in June 2013, as a result of flooding of the Elbe and Weser rivers. Several anomalous observations suggested that the hydrodynamical and biogeochemical states of the system were impacted by this event. In this study, we developed a biogeochemical model and coupled it with a previously introduced high-resolution hydrodynamical model of the southern North Sea in order to better characterize these impacts and gain insight into the underlying processes. Performance of the model was assessed using an extensive set of in situ measurements for the period 2011–2014. We first improved the realism of the hydrodynamic model with regard to the representation of cross-shore gradients, mainly through inclusion of flow-dependent horizontal mixing. Among other characteristic features of the system, the coupled model system can reproduce the low salinities, high nutrient concentrations and low oxygen concentrations in the bottom layers observed within the German Bight following the flood event. Through a scenario analysis, we examined the sensitivity of the patterns observed during July 2013 to the hydrological and meteorological forcing in isolation. Within the region of freshwater influence (ROFI) of the Elbe–Weser rivers, the flood event clearly dominated the changes in salinity and nutrient concentrations, as expected. However, our findings point to the relevance of the peculiarities in the meteorological conditions in 2013 as well: a combination of low wind speeds, warm air temperatures and cold bottom-water temperatures resulted in a strong thermal stratification in the outer regions and limited vertical nutrient transport to the surface layers. Within the central region, the thermal and haline dynamics interactively resulted in an intense density stratification. This intense stratification, in turn, led to enhanced primary production within the central region enriched by nutrients due to the flood but led to reduction within the nutrient-limited outer region, and it caused a widespread oxygen depletion in bottom waters. Our results further point to the enhancement of the current velocities at the surface as a result of haline stratification and to intensification of the thermohaline estuarine-like circulation in the Wadden Sea, both driven by the flood event. %0 journal article %@ 0022-1120 %A Buckley, M., Veron, F., Yousefi, K. %D 2020 %J Journal of Fluid Mechanics %P A31 %R doi:10.1017/jfm.2020.760 %T Surface viscous stress over wind-driven waves with intermittent airflow separation %U https://doi.org/10.1017/jfm.2020.760 %X The small-scale physics within the first centimetres above the wavy air–sea interface are the gateway for transfers of momentum and scalars between the atmosphere and the ocean. We present an experimental investigation of the surface wind stress over laboratory wind-generated waves. Measurements were performed at the University of Delaware's large wind-wave-current facility using a recently developed state-of-the-art wind-wave imaging system. The system was deployed at a fetch of 22.7 m, with wind speeds from 2.19 to 16.63 m s−1 . Airflow velocity fields were acquired using particle image velocimetry above the wind waves down to 100 μm above the surface, and wave profiles were detected using laser-induced fluorescence. The airflow intermittently separates downwind of wave crests, starting at wind speeds as low as 2.19 m s−1 . Such events are accompanied by a dramatic drop in tangential viscous stress past the wave's crest, and a gradual regeneration of the viscous sublayer upon the following (downwind) crest. This contrasts with non-airflow separating waves, where the surface viscous stress drop is less significant. Airflow separation becomes increasingly dominant with increasing wind speed and wave slope ak (where a and k are peak wave amplitude and wavenumber, respectively). At the highest wind speed ( 16.63 m s−1 ), airflow separation occurs over nearly 100 % of the wave crests. The total air–water momentum flux is partitioned between viscous stress and form drag at the interface. Viscous stress (respectively form drag) dominates at low (respectively high) wave slopes. Tangential viscous forcing makes a minor contribution ( ∼3% ) to wave growth. %0 journal article %@ 1559-128X %A Utschig, C., Röttgers, R. %D 2020 %J Applied Optics %N 33 %P 10554-10564 %R doi:10.1364/AO.393289 %T Mass-specific light absorption coefficients of mineral particles in aqueous suspension for the ultraviolet to near-infrared radiation spectral region (200–2500 nm) %U https://doi.org/10.1364/AO.393289 33 %X Light absorption by in-water suspended natural particles in the near-infrared radiation (NIR; 780–3000 nm) region has received little attention. Minerogenic matter is thought to be one source for NIR light absorption in aquatic environments. Here, mass-specific particulate light absorption coefficients of several particulate single minerals and mineral samples for the spectral range of 200–2500 nm are presented. The current methodology allows very sensitive measurements of particle suspension with a detection limit of about 2×10−6m2g−1 for the mass-specific absorption coefficient. Except for one, all mineral materials examined possessed significant light absorption throughout the full spectral range considered. The spectra revealed absorption features of specific elements (like iron) and from water structures (H2O, O-H bonds) in the mineral or crystal structure that have been known from reflectance measurements of minerals. The specific absorption in the NIR was as high as 0.02m2g−1 for laterite earths samples, but also below the detection limit for a steatite sample in a narrow spectral region (1600–1800 nm). The specific absorption by mineral particles in the NIR was, hence, highly variable from strong absorbing black minerals (magnetite) to low absorbing white clays. The information in the absorption coefficient spectrum can be used not only to identify specific mineral in natural particle assemblages but also to quantify their contribution to total particulate absorption in the NIR. %0 journal article %@ 0022-3670 %A Schubert, R., Gula, J., Greatbatch, R., Baschek, B., Biastoch, A. %D 2020 %J Journal of Physical Oceanography %N 9 %P 2573-2589 %R doi:10.1175/JPO-D-19-0311.1 %T The Submesoscale Kinetic Energy Cascade: Mesoscale Absorption of Submesoscale Mixed Layer Eddies and Frontal Downscale Fluxes %U https://doi.org/10.1175/JPO-D-19-0311.1 9 %X Mesoscale eddies can be strengthened by the absorption of submesoscale eddies resulting from mixed layer baroclinic instabilities. This is shown for mesoscale eddies in the Agulhas Current system by investigating the kinetic energy cascade with a spectral and a coarse-graining approach in two model simulations of the Agulhas region. One simulation resolves mixed layer baroclinic instabilities and one does not. When mixed layer baroclinic instabilities are included, the largest submesoscale near-surface fluxes occur in wintertime in regions of strong mesoscale activity for upscale as well as downscale directions. The forward cascade at the smallest resolved scales occurs mainly in frontogenetic regions in the upper 30 m of the water column. In the Agulhas ring path, the forward cascade changes to an inverse cascade at a typical scale of mixed layer eddies (15 km). At the same scale, the largest sources of the upscale flux occur. After the winter, the maximum of the upscale flux shifts to larger scales. Depending on the region, the kinetic energy reaches the mesoscales in spring or early summer aligned with the maximum of mesoscale kinetic energy. This indicates the importance of submesoscale flows for the mesoscale seasonal cycle. A case study shows that the underlying process is the mesoscale absorption of mixed layer eddies. When mixed layer baroclinic instabilities are not included in the simulation, the open-ocean upscale cascade in the Agulhas ring path is almost absent. This contributes to a 20% reduction of surface kinetic energy at mesoscales larger than 100 km when submesoscale dynamics are not resolved by the model. %0 journal article %@ 1932-6203 %A Metfies, K., Hessel, J., Klenk, R., Petersen, W., Wiltshire, K., Kraberg, A. %D 2020 %J PLoS One %N 6 %P e0233921 %R doi:10.1371/journal.pone.0233921 %T Uncovering the intricacies of microbial community dynamics at Helgoland Roads at the end of a spring bloom using automated sampling and 18S meta-barcoding %U https://doi.org/10.1371/journal.pone.0233921 6 %X In May 2016, the remote-controlled Automated Filtration System for Marine Microbes (AUTOFIM) was implemented in parallel to the Long Term Ecological Research (LTER) observatory Helgoland Roads in the German Bight. We collected samples for characterization of dynamics within the eukaryotic microbial communities at the end of a phytoplankton bloom via 18S meta-barcoding. Understanding consequences of environmental change for key marine ecosystem processes, such as phytoplankton bloom dynamics requires information on biodiversity and species occurrences with adequate temporal and taxonomic resolution via time series observations. Sampling automation and molecular high throughput methods can serve these needs by improving the resolution of current conventional marine time series observations. A technical evaluation based on an investigation of eukaryotic microbes using the partial 18S rRNA gene suggests that automated filtration with the AUTOFIM device and preservation of the plankton samples leads to highly similar 18S community profiles, compared to manual filtration and snap freezing. The molecular data were correlated with conventional microscopic counts. Overall, we observed substantial change in the eukaryotic microbial community structure during the observation period. A simultaneous decline of diatom and ciliate sequences succeeded a peak of Miracula helgolandica, suggesting a potential impact of these oomycete parasites on diatom bloom dynamics and phenology in the North Sea. As oomycetes are not routinely counted at Helgoland Roads LTER, our findings illustrate the benefits of combining automated filtration with metabarcodingto augment classical time series observations, particularly for taxa currently neglected due to methodological constraints. %0 journal article %@ 0079-6611 %A Macovei, V., Hartman, S., Schuster, U., Torres-Valdés, S., Moore, C., Sanders, R. %D 2020 %J Progress in Oceanography %P 102223 %R doi:10.1016/j.pocean.2019.102223 %T Impact of physical and biological processes on temporal variations of the ocean carbon sink in the mid-latitude North Atlantic (2002–2016) %U https://doi.org/10.1016/j.pocean.2019.102223 %X The ocean is currently a significant net sink for anthropogenically remobilised CO2, taking up around 24% of global emissions. Numerical models predict a diversity of responses of the ocean carbon sink to increased atmospheric concentrations in a warmer world. Here, we tested the hypothesis that increased atmospheric forcing is causing a change in the ocean carbon sink using a high frequency observational dataset derived from underway pCO2 (carbon dioxide partial pressure) instruments on ships of opportunity (SOO) and a fixed-point mooring between 2002 and 2016. We calculated an average carbon flux of 0.013 Pg yr−1 into the ocean at the Porcupine Abyssal Plain (PAP) site, consistent with past estimates. In spite of the increase in atmospheric pCO2, monthly average seawater pCO2 did not show a statistically significant increasing trend, but a higher annual variability, likely due to the decreasing buffer capacity of the system. The increasing led to an increasing trend in the estimated CO2 flux into the ocean of 0.19 ± 0.03 mmol m−2 day−1 per year across the entire 15 year time series, making the study area a stronger carbon sink. Seawater pCO2 variability is mostly influenced by temperature, alkalinity and dissolved inorganic carbon (DIC) changes, with 77% of the annual seawater pCO2 changes explained by these terms. DIC is in turn influenced by gas exchange and biological production. In an average year, the DIC drawdown by biological production, as determined from nitrate uptake, was higher than the DIC increase due to atmospheric CO2 dissolution into the surface ocean. This effect was enhanced in years with high nutrient input or shallow mixed layers. Using the rate of change of DIC and nitrate, we observed Redfieldian carbon consumption during the spring bloom at a C:N ratio of 6.2 ± 1.6. A comparison between SOO and PAP sustained observatory data revealed a strong agreement for pCO2 and DIC. This work demonstrates that the study area has continued to absorb atmospheric CO2 in recent years with this sink enhancing over time. Furthermore, the change in pCO2 per unit nitrate became larger as surface buffer capacity changed. %0 journal article %@ 2296-7745 %A Daniel, A., Laës-Huon, A., Barus, C., Beaton, A., Blandfort, D., Guigues, N., Knockaert, M., Munaron, D., Salter, I., Woodward, E., Greenwood, N., Achterberg, E. %D 2020 %J Frontiers in Marine Science %P 773 %R doi:10.3389/fmars.2019.00773 %T Toward a Harmonization for Using in situ Nutrient Sensors in the Marine Environment %U https://doi.org/10.3389/fmars.2019.00773 %X Improved comparability of nutrient concentrations in seawater is required to enhance the quality and utility of measurements reported to global databases. Significant progress has been made over recent decades in improving the analysis and data quality for traditional laboratory measurements of nutrients. Similar efforts are required to establish high-quality data outputs from in situ nutrient sensors, which are rapidly becoming integral components of ocean observing systems. This paper suggests using the good practices routine established for laboratory reference methods to propose a harmonized set of deployment protocols and of quality control procedures for nutrient measurements obtained from in situ sensors. These procedures are intended to establish a framework to standardize the technical and analytical controls carried out on the three main types of in situ nutrient sensors currently available (wet chemical analyzers, ultraviolet optical sensors, electrochemical sensors) for their deployments on all kinds of platform. The routine reference controls that can be applied to the sensors are listed for each step of sensor use: initial qualification under controlled conditions in the laboratory, preparation of the sensor before deployment, field deployment and finally the sensor recovery. The fundamental principles applied to the laboratory reference method are then reviewed in terms of the calibration protocol, instrumental interferences, environmental interferences, external controls, and method performance assessment. Data corrections (linearity, sensitivity, drifts, interferences and outliers) are finally identified along with the concepts and calculations for qualification for both real time and time delayed data. This paper emphasizes the necessity of future collaborations between research groups, reference-accredited laboratories, and technology developers, to maintain comparability of the concentrations reported for the various nutrient parameters measured by in situ sensors. %0 journal article %@ 2169-9275 %A Rascle, N., Chapron, B., Molemaker, J., Nouguier, F., Ocampo-Torres, F., Osuna Cañedo, J., Marié, L., Lund, B., Horstmann, J. %D 2020 %J Journal of Geophysical Research : Oceans %N 8 %P e2019JC015704 %R doi:10.1029/2019JC015704 %T Monitoring Intense Oceanic Fronts Using Sea Surface Roughness: Satellite, Airplane, and In Situ Comparison %U https://doi.org/10.1029/2019JC015704 8 %X Sea surface roughness is affected by surface current gradients, which provides a means of monitoring from satellite sharp oceanic fronts. This paper is the second report of an experiment designed to compare observations of sea surface roughness and surface currents at an unprecedented accuracy, owing to the conjunction of numerous deployed drifters and roughness instruments. About 200 drifters sampled a thin 10~km elongated submesoscale front, also monitored by a high density of roughness instruments: satellite Synthetic Aperture Radar, satellite and airborne multi‐angle sunglint radiometers. The first paper focused on the retrieval of the current gradient direction (convergence and cyclonic vorticity) at the front, using roughness observations at multiple angle from airplane. This second paper focuses on the retrieval of the current gradient magnitude and scale, using roughness observations at different scales, from airplane and from satellite. Two main results are obtained: (i) Trajectories of selected drifters show that the front is only 50~m wide and unambiguously exhibits convergence and cyclonic vorticity up to 100~f (with f the Coriolis frequency). This far exceeds previously documented values for submesoscale deep ocean fronts. (ii) Correct estimation of such extreme current gradients using surface roughness hinges on instruments with sufficiently high spatial resolution. Lower resolution roughness sensors can still detect the front, as demonstrated from observations and a simplified model, but cannot properly estimate the current gradient magnitude and the frontal width. Those results provide guidelines for monitoring intense current gradients from space using sea surface roughness. %0 online contribution %@ %A Streßer, M., Eschenbach, C. %D 2020 %J Earth System Knowledge Platform [eskp.de] %R doi:10.2312/eskp.040 %T Meereswellen an Küsten besser verstehen %U https://doi.org/10.2312/eskp.040 %X Brechende Wellen setzen viel Energie frei. Daher sorgen Meereswellen, die auf die Küste treffen, dort beispielweise für Erosion und sie können für Deiche und Bauten gefährlich werden. Wir müssen Wellen und damit verbundene Prozesse besser verstehen, um mögliche Folgen des Klimawandels und menschlicher Eingriffe abschätzen zu können. %0 journal article %@ 1942-2466 %A Carroll, D., Menemenlis, D., Adkins, J., Bowman, K., Brix, H., Dutkiewicz, S., Fenty, I., Gierach, M., Hill, C., Jahn, O., Landschützer, P., Lauderdale, J., Liu, J., Manizza, M., Naviaux, J., Rödenbeck, C., Schimel, D., Van der Stocken, T., Zhang, H. %D 2020 %J Journal of Advances in Modeling Earth Systems %N 10 %P e2019MS001888 %R doi:10.1029/2019MS001888 %T The ECCO‐Darwin Data‐Assimilative Global Ocean Biogeochemistry Model: Estimates of Seasonal to Multidecadal Surface Ocean pCO2 and Air‐Sea CO2 Flux %U https://doi.org/10.1029/2019MS001888 10 %X Quantifying variability in the ocean carbon sink remains problematic due to sparse observations and spatiotemporal variability in surface ocean pCO2. To address this challenge, we have updated and improved ECCO‐Darwin, a global ocean biogeochemistry model that assimilates both physical and biogeochemical observations. The model consists of an adjoint‐based ocean circulation estimate from the Estimating the Circulation and Climate of the Ocean (ECCO) consortium and an ecosystem model developed by the Massachusetts Institute of Technology Darwin Project. In addition to the data‐constrained ECCO physics, a Green’s Function approach is used to optimize the biogeochemistry by adjusting initial conditions and six biogeochemical parameters. Over seasonal to multi‐decadal timescales (1995–2017), ECCO‐Darwin exhibits broad‐scale consistency with observed surface ocean pCO2 and air‐sea CO2 flux reconstructions in most biomes, particularly in the subtropical and equatorial regions. The largest differences between CO2 uptake occur in subpolar, seasonally‐stratified biomes, where ECCO‐Darwin results in stronger winter uptake. Compared to the Global Carbon Project OBMs, ECCO‐Darwin has a time‐mean, global‐ocean CO2 sink (2.47 ± 0.50 Pg C year‐1) and interannual variability that are more consistent with interpolation‐based products. Compared to interpolation‐based methods, ECCO‐Darwin is less sensitive to sparse and irregularly‐sampled observations. Thus, ECCO‐Darwin provides a basis for identifying and predicting the consequences of natural and anthropogenic perturbations to the ocean carbon cycle, as well as the climate‐related sensitivity of marine ecosystems. Our study further highlights the importance of physically‐consistent, property‐conserving reconstructions, as are provided by ECCO, for ocean biogeochemistry studies. %0 journal article %@ 2169-9275 %A Lund, B., Haus, B., Graber, H., Horstmann, J., Carracso, R., Novelli, G., Guigand, C., Mehta, S., Laxague, N., Özgökmen, T. %D 2020 %J Journal of Geophysical Research : Oceans %N 2 %P e2019JC015618 %R doi:10.1029/2019JC015618 %T Marine X‐Band Radar Currents and Bathymetry: An Argument for a Wave Number‐Dependent Retrieval Method %U https://doi.org/10.1029/2019JC015618 2 %X This study evaluates shipboard marine X‐band radar (MR) near‐surface current and bathymetry measurements under shallow water conditions. The retrieval algorithm is based on the surface wave signal within three‐dimensional wave number frequency MR backscatter intensity variance spectra. The MR data were collected during a research cruise that investigated submesoscale processes and their impact on oil spill transport in the Louisiana Bight. The MR currents and bathymetry are validated using measurements from 500 GPS‐equipped surface drifters, a shipboard acoustic Doppler current profiler, and a shipboard single‐beam echo sounder. Earlier results from the same experiment but using a different set of sensors indicate strong upper ocean vertical current shear over a 3.5 hr period, despite only mild wind forcing. Here, the MR currents are derived as a function of wave number, providing a measure of vertical shear for the full duration of the cruise. Strong vertical shear is frequently observed, with a maximum difference of 0.42 m/s between the MR high (effective depth of urn:x-wiley:jgrc:media:jgrc23817:jgrc23817-math-00010.9 m) and low ( urn:x-wiley:jgrc:media:jgrc23817:jgrc23817-math-00022.4 m) wave number bins. Treating the drifter and echo sounder measurements as truth, the accuracies of the MR near‐surface currents and bathymetry are 0.04–0.07 m/s and 1.2 m (or 7% of the mean water depth). However, it is shown that urn:x-wiley:jgrc:media:jgrc23817:jgrc23817-math-000350% of the MR high wave number and drifter current differences is due to vertical shear. The shallow water MR near‐surface current accuracy thus matches findings from a previous deep water validation where vertical shear was much weaker. %0 online contribution %@ %A Zhang, W., Eschenbach, C. %D 2020 %J ESKP-Themenspezial Biodiversität im Meer und an Land. Vom Wert biologischer Vielfalt %P 33-38 %R doi:10.2312/eskp.2020.1.1.6 %T Bedeutung der Biodiversität für Ökosystemfunktionen und Küstenformen %U https://doi.org/10.2312/eskp.2020.1.1.6 %X Küsten sind nicht nur besondere und artenreiche Lebensräume, sondern übernehmen auch wichtige Funktionen für uns Menschen. Sie unterliegen ständigen Veränderungen, ihre Gestalt und die zukünftige Entwicklung der Küsten sind das Ergebnis vielfältiger Wechselwirkungen. Daher reagieren sie sehr empfindlich auf den Klimawandel und andere anthropogene Umwelteinwirkungen. Am Beispiel des Wattenmeeres wird deutlich, dass die Wechselwirkungen zwischen biologischen und physikalischen Vorgängen entscheidend sind für das Verständnis der Küstenzonen und ihrer Veränderungen. ■ Küstenzonen sind Lebensraum für eine große Vielzahl von Lebewesen. ■ Küsten unterliegen im Zusammenhang mit dem Klimawandel tiefgreifenden Veränderungen. ■ Diese lassen sich aber nur verstehen, wenn man die dynamischen Wechselwirkungen zwischen den physikalischen und den biologischen Prozessen betrachtet. ■ Hier erfolgt das am Beispiel des einzigartigen Lebensraumes Wattenmeer. %0 journal article %@ 2169-9275 %A Pearson, J., Fox-Kemper, B., Pearson, B., Chang, H., Haus, B., Horstmann, J., Huntley, H., Kirwan Jr, A., Lund, B., Poje, A. %D 2020 %J Journal of Geophysical Research : Oceans %N 6 %P e2019JC015769 %R doi:10.1029/2019JC015769 %T Biases in Structure Functions from Observations of Submesoscale Flows %U https://doi.org/10.1029/2019JC015769 6 %X Surface drifter observations from the LAgrangian Submesoscale ExpeRiment (LASER) campaign in the Gulf of Mexico are paired with Eulerian (ship‐borne X‐band radar) data to demonstrate that velocity structure functions from drifters differ systematically from Eulerian structure functions over scales from 0.4 to 7 km. These differences result from drifters oversampling surface convergences and regions of intense vorticity. The first‐, second‐, and third‐order structure functions are calculated using quasi‐Lagrangian (drifter) and Eulerian data from approximately the same location and time. Differences between quasi‐Lagrangian and Eulerian structure functions are attributed to two forms of bias. The first bias results from the mean divergence or vorticity of the background flow creating nonzero first‐order structure functions. This background bias affects both quasi‐Lagrangian and Eulerian data when insufficiently time‐averaged. It severely biases the drifter third‐order structure functions but is smaller in Eulerian structure functions at both second and third order. This bias can be corrected for using lower‐order structure functions. The second form of bias results from drifters accumulating in regions with flow statistics that differ from undersampled regions. This accumulation bias is diagnosed by identifying the dependence of the Eulerian structure functions on divergence and vorticity as well as scale. Together, both biases suggest that caution is needed when interpreting second‐order drifter statistics and that linking raw third‐order drifter statistics to energy fluxes is often erroneous in ocean data: Even with background correction and sufficient time‐averaging, drifters overestimate the Eulerian estimate of the third‐order structure function by up to a factor of 5 when signs are consistent. %0 journal article %@ 2296-7745 %A Giering, S., Cavan, E., Basedow, S, Briggs, N., Burd, A., Darroch, L., Guidi, L., Irisson, J., Iversen, M., Kiki, R., Lindsay, D., Marcolin, C., McDonnell, A., Möller, K., Passow, U., Thomalla, S., Trull, T., Waite, A. %D 2020 %J Frontiers in Marine Science %P 834 %R doi:10.3389/fmars.2019.00834 %T Sinking Organic Particles in the Ocean—Flux Estimates From in situ Optical Devices %U https://doi.org/10.3389/fmars.2019.00834 %X Optical particle measurements are emerging as an important technique for understanding the ocean carbon cycle, including contributions to estimates of their downward flux, which sequesters carbon dioxide (CO2) in the deep sea. Optical instruments can be used from ships or installed on autonomous platforms, delivering much greater spatial and temporal coverage of particles in the mesopelagic zone of the ocean than traditional techniques, such as sediment traps. Technologies to image particles have advanced greatly over the last two decades, but the quantitative translation of these immense datasets into biogeochemical properties remains a challenge. In particular, advances are needed to enable the optimal translation of imaged objects into carbon content and sinking velocities. In addition, different devices often measure different optical properties, leading to difficulties in comparing results. Here we provide a practical overview of the challenges and potential of using these instruments, as a step toward improvement and expansion of their applications. %0 journal article %@ 1424-8220 %A Carlson, D.F., Pavalko, W.J., Petersen, D., Olsen, M., Hass, A.E. %D 2020 %J Sensors %N 5 %P 1254 %R doi:10.3390/s20051254 %T Maker Buoy Variants for Water Level Monitoring and Tracking Drifting Objects in Remote Areas of Greenland %U https://doi.org/10.3390/s20051254 5 %X Meltwater runoff from the Greenland Ice Sheet changes water levels in glacial lakes and can lead to glacial lake outburst flooding (GLOF) events that threaten lives and property. Icebergs produced at Greenland’s marine terminating glaciers drift into Baffin Bay and the North Atlantic, where they can threaten shipping and offshore installations. Thus, monitoring glacial lake water levels and the drift of icebergs can enhance safety and aid in the scientific studies of glacial hydrology and iceberg-ocean interactions. The Maker Buoy was originally designed as a low-cost and open source sensor to monitor surface ocean currents. The open source framework, low-cost components, rugged construction and affordable satellite data transmission capabilities make it easy to customize for environmental monitoring in remote areas and under harsh conditions. Here, we present two such Maker Buoy variants that were developed to monitor water level in an ice-infested glacial lake in southern Greenland and to track drifting icebergs and moorings in the Vaigat Strait (Northwest Greenland). We describe the construction of each design variant, methods to access data in the field without an internet connection, and deployments in Greenland in summer 2019. The successful deployments of each Maker Buoy variant suggest that they may also be useful in operational iceberg management strategies and in GLOF monitoring programs. %0 journal article %@ 2296-7745 %A Mantovani, C., Corgnati, L., Horstmann, J., Rubio, A., Reyes, E., Quentin, C., Cosoli, S., Asensio, J., Mader, J., Griffa, A. %D 2020 %J Frontiers in Marine Science %P 210 %R doi:10.3389/fmars.2020.00210 %T Best Practices on High Frequency Radar Deployment and Operation for Ocean Current Measurement %U https://doi.org/10.3389/fmars.2020.00210 %X High Frequency Radar (HFR) technology refers to land based remote sensing instruments capable of measuring surface currents and ocean waves at ranges up to 200 km or more. HFR technology is widely acknowledged as a cost-efficient tool to monitor coastal regions and has potential use to monitor coastal regions all over the world. Globally, the number of HFR stations is steadily increasing. Regional networks provide real-time data in support of operational activities such as search and rescue operations, fast response in case of maritime accidents and spill of pollutants, and resource management. Each operator needs a general understanding of the working principles in order to ensure that instruments are managed properly. A set of harmonized quality assurance and quality control procedures is recommended, along with an effective approach to HFR data discovery and dissemination, to provide high quality measurements to the end users. Different documents providing best practices for operation and maintenance have emerged in the past years. They are oriented either to Direction Finding (DF) or Beam Forming (BF) systems, or to specific manufacturer’s radar systems. The main objective of this paper is to offer a comprehensive “Best Practices” document in an effort of ensuring consistency between different deployments and harmonized operations of HFR systems. This, regardless of system manufacturer, antenna design and setup. A homogeneous approach is given when possible, general concepts and definitions are introduced in order to provide a framework for both data processing and management steps. Examples are also given from the European HFR users with focus on Near Real Time data flow suitable for operational services. %0 journal article %@ 2296-6463 %A Dupouy, C., Röttgers, R., Tedetti, M., Frouin, R., Lantoine, F., Rodier, M., Martias, C., Goutx, M. %D 2020 %J Frontiers in Earth Science %P 54 %R doi:10.3389/feart.2020.00054 %T Impact of Contrasted Weather Conditions on CDOM Absorption/Fluorescence and Biogeochemistry in the Eastern Lagoon of New Caledonia %U https://doi.org/10.3389/feart.2020.00054 %X New Caledonia (Southwest Pacific), like all tropical Pacific Island countries, is impacted by weather events, climate change, and local anthropogenic forcing. Strong erosion of particles and dissolved organic matter (DOM) from ultramafic rocks, associated with trace metals dissemination (i.e., nickel, manganese and cobalt), potentially affects lagoon waters and coral reefs surrounding the main island. The CALIOPE (CALedonian Inherent Optical PropErties) cruises were performed along the Eastern Lagoon of New Caledonia (ELNC) (400 km, 13 transects from Bay to open ocean, 51 stations) during contrasted meteorological conditions: a dry period (October 2011), a windy situation (March 2014), and a strong rainy event (March 2016). CDOM absorption and fluorescence (FDOM), particulate absorption, backscattering, suspended particulate matter (SPM), total chlorophyll a (TChla), nutrients (NOx), pigment and phytoplankton composition were measured. Among the four CDOM fluorophores, the humic-like component (λEx/λEm: 235/460 nm), assimilated to a photoproduct of terrestrial organic matter, had relatively low fluorescence compared to protein-like fluorophores. As CDOM absorption, particulate absorption, backscattering, SPM, total chlorophyll a (TChla) and nutrient (NOx) concentrations, this humic-like material generally showed the highest values during rainfall events, the latter inducing an increase in riverine terrigeneous inputs and change toward higher phytoplankton size classes. The tyrosine 1-like (λEx/λEm: 220, 275/304 nm) and tryptophan-like fluorophores (λEx/λEm: 230, 300/352 nm) were strongly influenced by wind displaying a 7-fold and 3-fold increase, respectively in windy situation compared to calm conditions. These increases could be related to enhancements of autochthonous biological activities (highest mean concentrations of Synechococcus spp., phycoerythrin, pico- and nano-eukaryotes, heterotrophic bacteria and nanoplankton observed in wind condition) through the inputs of organic and mineral materials issued from the wind-induced sediment resuspension, atmospheric deposition and water mass mixing. By contrast, the tyrosine 2-like fluorophore (λEx/λEm: 245, 275/304 nm) substantially increased during rain events and presented the lowest values in wind conditions. These strong increases may be linked to the stimulation of planktonic activities due to riverine inputs. Therefore, this study emphasizes the significant differential influence of weather conditions (calm/wind/rain) on biogeochemistry and CDOM/FDOM distributions in the ELNC. %0 editorial %@ 2673-1924 %A Bode, A., Abrantes, F., Antunes, A., Benetazzo, A., Chen, C., Devred, E., Gade, M., Gràcia, E., Horstmann, J., Macias, D., Maina, J., Masqué, P., Meskhidze, N., Somoza, L. %D 2020 %J Oceans %N 1 %P 1-5 %R doi:10.3390/oceans1010001 %T MDPI Oceans: A New Publication Channel for Open Access Science Focused on the Ocean %U https://doi.org/10.3390/oceans1010001 1 %X The ocean is the most important subsystem of the Earth’s climate system and functions as its heart, regulating the energy distribution of the planet [...] %0 journal article %@ 1812-0784 %A Onken, R., Baschek, B., Angel-Benavides, I. %D 2020 %J Ocean Science %N 3 %P 657-684 %R doi:10.5194/os-16-657-2020 %T Very high-resolution modelling of submesoscale turbulent patterns and processes in the Baltic Sea %U https://doi.org/10.5194/os-16-657-2020 3 %X In order to simulate submesoscale turbulent patterns and processes (STPPs) and to analyse their properties and dynamics, the Regional Ocean Modeling System (ROMS) was run for June 2016 in a subregion of the Baltic Sea. To create a realistic mesoscale environment, ROMS with 500 m horizontal resolution (referred to as R500) is one-way nested into an existing operational model, and STPPs with horizontal scales  < 1 km are resolved with a second nest of 100 m resolution (R100). Both nests use 10 terrain-following layers in the vertical. The comparison of the R500 results with a satellite image shows fair agreement. While R500 is driven by realistic air–sea fluxes, the atmospheric forcing is turned off in R100 because it prevents the generation of STPPs and blurs submesoscale structures. Therefore, R100 provides deep insight into ageostrophic processes and associated quantities under quasi-adiabatic conditions that are approximately met in no-wind or light-wind situations. The validity of the results is furthermore limited to the selected region and the time of the year. STPPs evolve rapidly within a about a day. They are characterized by vertical speeds of 𝒪(10) m d−1 and relative vorticities and divergences reaching multiples of the Coriolis parameter. Typical elements of the secondary circulation of two-dimensional strain-induced frontogenesis are identified at an exemplary front in shallow water, and details of the ageostrophic flow field are revealed. The conditions for inertial and symmetric instability are evaluated for the whole domain, and the components of the tendency equation are computed in a subregion. While anticyclonic eddies are generated solely along coasts, cyclonic eddies are rolled-up streamers and found in the entire domain. A special feature of the cyclones is their ability to absorb internal waves and to sustain patches of continuous upwelling for several days, favouring plankton growth. The kinematic properties show good agreement with observations, while some observed details within a small cyclonic eddy are only partly reproduced, most likely due to a lack of horizontal resolution or nonhydrostatic effects. %0 journal article %@ 2072-4292 %A Tilstone, G., Dall'Olmo, G., Hieronymi, M., Ruddick, K., Beck, M., Ligi, M., Costa, M., D'Alimonte, D., Velluci, V., Vansteenwegen, D., Bracher, A., Wiegmann, S., Kuusk, J., Vabson, V., Ansko, I., Vendt, R., Donlon, C., Casal, T. %D 2020 %J Remote Sensing %N 10 %P 1587 %R doi:10.3390/rs12101587 %T Field Intercomparison of Radiometer Measurements for Ocean Colour Validation %U https://doi.org/10.3390/rs12101587 10 %X A field intercomparison was conducted at the Acqua Alta Oceanographic Tower (AAOT) in the northern Adriatic Sea, from 9 to 19 July 2018 to assess differences in the accuracy of in- and above-water radiometer measurements used for the validation of ocean colour products. Ten measurement systems were compared. Prior to the intercomparison, the absolute radiometric calibration of all sensors was carried out using the same standards and methods at the same reference laboratory. Measurements were performed under clear sky conditions, relatively low sun zenith angles, moderately low sea state and on the same deployment platform and frame (except in-water systems). The weighted average of five above-water measurements was used as baseline reference for comparisons. For downwelling irradiance ( Ed ), there was generally good agreement between sensors with differences of <6% for most of the sensors over the spectral range 400 nm–665 nm. One sensor exhibited a systematic bias, of up to 11%, due to poor cosine response. For sky radiance ( Lsky ) the spectrally averaged difference between optical systems was <2.5% with a root mean square error (RMS) <0.01 mWm−2 nm−1 sr−1. For total above-water upwelling radiance ( Lt ), the difference was <3.5% with an RMS <0.009 mWm−2 nm−1 sr−1. For remote-sensing reflectance ( Rrs ), the differences between above-water TriOS RAMSES were <3.5% and <2.5% at 443 and 560 nm, respectively, and were <7.5% for some systems at 665 nm. Seabird-Hyperspectral Surface Acquisition System (HyperSAS) sensors were on average within 3.5% at 443 nm, 1% at 560 nm, and 3% at 665 nm. The differences between the weighted mean of the above-water and in-water systems was <15.8% across visible bands. A sensitivity analysis showed that Ed accounted for the largest fraction of the variance in Rrs , which suggests that minimizing the errors arising from this measurement is the most important variable in reducing the inter-group differences in Rrs . The differences may also be due, in part, to using five of the above-water systems as a reference. To avoid this, in situ normalized water-leaving radiance ( Lwn ) was therefore compared to AERONET-OC SeaPRiSM Lwn as an alternative reference measurement. For the TriOS-RAMSES and Seabird-HyperSAS sensors the differences were similar across the visible spectra with 4.7% and 4.9%, respectively. The difference between SeaPRiSM Lwn and two in-water systems at blue, green and red bands was 11.8%. This was partly due to temporal and spatial differences in sampling between the in-water and above-water systems and possibly due to uncertainties in instrument self-shading for one of the in-water measurements %0 online contribution %@ %A Eschenbach, C., Krasemann, H. %D 2020 %J ESKP-Themenspezial Biodiversität im Meer und an Land. Vom Wert biologischer Vielfalt %P 162-166 %R doi:10.2312/eskp.2020.1.7.4 %T Die Bestimmung von Phytoplanktongruppen durch Fernerkundung in Küstengewässern %U https://doi.org/10.2312/eskp.2020.1.7.4 %X Kleinste, im Meer driftende Algen produzieren etwa die Hälfte des in der Atmosphäre weltweit vorhandenen Sauerstoffs. Gleichzeitig nimmt der Ozean etwa ein Drittel des jährlich von Menschen freigesetzten CO₂ wieder auf. Das Phytoplankton bildet zudem die Basis des marinen Nahrungsnetzes und ist deshalb entscheidend für das Vorkommen und die Artengemeinschaften anderer Meeresorganismen. Es sichert somit viele wichtige Ökosystemleistungen. Jedoch können Algenblüten auch toxisch sein und die Fischerei beeinträchtigen. ■ Die Überdüngung der Meere wie auch der Klimawandel könnten großräumige Veränderungen des Phytoplanktons mit sich bringen. ■ Mit Hilfe von hoch auflösenden Fernerkundungsdaten und komplexen Berechnungen werden das Auftreten und die Ausbreitung von Algenblüten überwacht. ■ Neuerdings gelingt sogar die Bestimmung einzelner Algengruppen per Satellit. %0 dataset %@ %A Carlson, D., Treier, U., Sejr, M., Meire, L., Markager, S. %D 2020 %J Zenodo %R doi:10.5281/zenodo.4309851 %T 3D mesh model and raw images of a drifting iceberg in Dickson Fjord (NE Greenland) on 20 August 2018 at 12:41 UTC [Data set] %U https://doi.org/10.5281/zenodo.4309851 %X This dataset consists of low-altitude aerial imagery that was acquired by a DJI Phantom 3 Standard unoccupied aerial vehicle (UAV) in Dickson Fjord in northeast Greenland on 20 August 2018. The UAV survey commenced at 12:41 UTC. These images were processed in Agisoft PhotoScan Pro (v1.4; Linux Ubuntu). During the image alignment step in PhotoScan, the ‘High’ accuracy setting and key point and tie point limits of 60000 and 0 were used. Generic and reference preselection were disabled. Gradual selection was used to remove tie points that exceeded thresholds for the projection accuracy, reconstruction uncertainty, and reprojection error and the lens parameters were computed. Reference data from images DJI_493-497 were used to scale the sparse point cloud. The dense point cloud was then computed using the ‘High’ setting, followed by the textured mesh. The mesh model was exported in .obj and .pdf formats. %0 journal article %@ 0022-4073 %A Zhao, Y., Poulin, C., McKee, D., Hu, L., Agagliate, J., Yang, P., Xiaodong, Z. %D 2020 %J Journal of Quantitative Spectroscopy and Radiative Transfer %P 106730 %R doi:10.1016/j.jqsrt.2019.106730 %T A closure study of ocean inherent optical properties using flow cytometry measurements %U https://doi.org/10.1016/j.jqsrt.2019.106730 %X Flow cytometry and inherent optical property measurements of UK coastal waters were used to evaluate optical closure of different combinations of models for particle size, refractive index and shape. The particle size and refractive index distributions were derived from flow cytometry measurements and subsequently simplified through averaging down to the simplest model consisting of a Junge size distribution with a single bulk refractive index. Models for particle shapes included homogeneous spheres, coated spheres, and hexahedra. The simplest particle model, based on a Junge size distribution and a single bulk refractive index, gave the poorest quality of closure, suggesting that it underestimates particle complexity in the sampled waters. Other particle models using more detailed combinations of size and refractive index distributions gave broadly equivalent results for absorption and scattering. Backscattering was better represented by the most complex particle size and refractive index model, indicating that backscattering is sensitive to those factors. The homogeneous spherical model gave relatively good results, which is expected because the inversion of size and refractive index distributions from flow cytometry is based on the homogeneous spherical model using forward and side scattering signals. Lorenz-Mie theory, assuming homogeneous spheres, provided optical closure that was generally as accurate as models with more complex particle shape and structure. Cumulative contribution simulations revealed that particles between 0.5 and 20 µm substantially contributed to attenuation, scattering and backscattering, while particles larger than 20 µm mainly contributed to absorption and small particles (< 0.5 µm) contribute to 30–40% of backscattering. %0 journal article %@ 2296-7745 %A Fischer, P., Brix, H., Baschek, B., Kraberg, A., Brand, M., Cisewski, B., Riethmüller, R., Breitbach, G., Möller, K., Gattuso, J., Alliouane, S., van de Poll, W., Witbaard, R. %D 2020 %J Frontiers in Marine Science %P 551 %R doi:10.3389/fmars.2020.00551 %T Operating Cabled Underwater Observatories in Rough Shelf-Sea Environments: A Technological Challenge %U https://doi.org/10.3389/fmars.2020.00551 %X Cabled coastal observatories are often seen as future-oriented marine technology that enables science to conduct observational and experimental studies under water year-round, independent of physical accessibility to the target area. Additionally, the availability of (unrestricted) electricity and an Internet connection under water allows the operation of complex experimental setups and sensor systems for longer periods of time, thus creating a kind of laboratory beneath the water. After successful operation for several decades in the terrestrial and atmospheric research field, remote controlled observatory technology finally also enables marine scientists to take advantage of the rapidly developing communication technology. The continuous operation of two cabled observatories in the southern North Sea and off the Svalbard coast since 2012 shows that even highly complex sensor systems, such as stereo-optical cameras, video plankton recorders or systems for measuring the marine carbonate system, can be successfully operated remotely year-round facilitating continuous scientific access to areas that are difficult to reach, such as the polar seas or the North Sea. Experience also shows, however, that the challenges of operating a cabled coastal observatory go far beyond the provision of electricity and network connection under water. In this manuscript, the essential developmental stages of the “COSYNA Shallow Water Underwater Node” system are presented, and the difficulties and solutions that have arisen in the course of operation since 2012 are addressed with regard to technical, organizational and scientific aspects. %0 journal article %@ 2073-4441 %A Yakushev, E., Wallhead, P., Renaud, P., Ilinskaya, A., Protsenko, E., Yakubov, S., Pakhomova, S., Sweetman, A., Dunlop, K., Berezina, A., Bellerby, R., Dale, T. %D 2020 %J Water %N 9 %P 2384 %R doi:10.3390/w12092384 %T Understanding the Biogeochemical Impacts of Fish Farms Using a Benthic-Pelagic Model %U https://doi.org/10.3390/w12092384 9 %X Sustainable development of the salmon farming industry requires knowledge of the biogeochemical impacts of fish farm emissions. To investigate the spatial and temporal scales of farm impacts on the water column and benthic biogeochemistry, we coupled the C-N-P-Si-O-S-Mn-Fe transformation model BROM with a 2-dimensional benthic-pelagic transport model (2DBP), considering vertical and horizontal transport in the water and upper 5 cm of sediments along a 10 km transect centered on a fish farm. The 2DBP model was forced by hydrophysical model data for the Hardangerfjord in western Norway. Model simulations showed reasonable agreement with field data from the Hardangerfjord in August 2016 (correlations between the model and observations were significant for most variables, and model biases were mostly <35%). The model predicted significant impacts on seafloor biogeochemistry up to 1 km from the fish farm (e.g., increased organic matter in sediments, oxygen depletion in bottom water and sediments, denitrification, metal and sulfur reduction), as well as detectable decreases in oxygen and increases in ammonium, phosphate and organic matter in the surface water near to the fish farm. %0 journal article %@ 2469-990X %A Carpenter, J., Guha, A. %D 2020 %J Physical Review Fluids %N 6 %P 064702 %R doi:10.1103/PhysRevFluids.5.064702 %T Motion of buoyant point vortices %U https://doi.org/10.1103/PhysRevFluids.5.064702 6 %X A general formulation is presented for studying the motion of buoyant vortices in a homogeneous ambient fluid. It extends the well-known Hamiltonian framework for interacting homogeneous point vortices to include buoyancy effects acting on the vortices. This is then used to systematically examine the buoyant one-, two-, and three-vortex problems. In doing so we find that two buoyant vortices may evolve either as a pair in bounded circular orbits or as two independent unbounded vortices that drift apart, and a criterion is found to distinguish these cases. Special attention is given to the buoyant vortex couple, consisting of two vortices of equal and opposite circulation and equal buoyancy anomaly. We show that a theoretical maximum height is generally possible for the rise (or fall) of such couples against buoyancy forces. Finally, the possibility and onset of chaotic motions in the buoyant three-vortex problem are addressed. In contrast to the homogeneous three-vortex problem, the buoyant vortex system shows evidence that chaos is present. We also demonstrate the chaotic advection of tracer parcels arising from the flow field induced by just two buoyant vortices. %0 journal article %@ 2169-8961 %A Omar, A., Thomas, H., Olsen, A., Becker, M., Skjelvan, I., Reverdin, G. %D 2019 %J Journal of Geophysical Research : Biogeosciences %N 10 %P 3088-3103 %R doi:10.1029/2018JG004992 %T Trends of Ocean Acidification and pCO2 in the Northern North Sea, 2003–2015 %U https://doi.org/10.1029/2018JG004992 10 %X In the northern North Sea, pCO2, pH, and Ωar are subject to strong seasonal variations with mean wintertime values of 375 ± 11 μatm, 8.17 ± 0.01, and 1.96 ± 0.05. Dissolved inorganic carbon is found to be the primary driver of both seasonal and interannual changes while total alkalinity and sea surface temperature have secondary effects that reduce the changes produced by dissolved inorganic carbon. Average interannual variations during winter are around 3%, 0.1%, and 2% for pCO2, pH, and Ωar, respectively and slightly larger in the eastern part of the study area (Skagerrak region) than in the western part (North Atlantic Water region). Statistically significant long‐term trends were found only in the North Atlantic Water region with mean annual rates of 2.39 ± 0.58 μatm/year, −0.0024 ± 0.001 year‐1, and −0.010 ± 0.003 year‐1 for pCO2, pH, and Ωar, respectively. The drivers of the observed trends as well as reasons for the lack of statistically significant trends in the Skagerrak region are discussed. %0 book %@ %A Smyth, W.D., Carpenter, J.R. %D 2019 %J %R doi:10.1017/9781108640084 %T Instability in Geophysical Flows %U https://doi.org/10.1017/9781108640084 %X Instabilities are present in all natural fluids from rivers to atmospheres. This book considers the physical processes that generate instability. Part I describes the normal mode instabilities most important in geophysical applications, including convection, shear instability and baroclinic instability. Classical analytical approaches are covered, while also emphasising numerical methods, mechanisms such as internal wave resonance, and simple `rules of thumb' that permit assessment of instability quickly and intuitively. Part II introduces the cutting edge: nonmodal instabilities, the relationship between instability and turbulence, self-organised criticality, and advanced numerical techniques. Featuring numerous exercises and projects, the book is ideal for advanced students and researchers wishing to understand flow instability and apply it to their own research. It can be used to teach courses in oceanography, atmospheric science, coastal engineering, applied mathematics and environmental science. Exercise solutions and MATLAB® examples are provided online. Also available as Open Access on Cambridge Core. %0 journal article %@ 0997-7546 %A Buckley, M.P., Veron, F. %D 2019 %J European Journal of Mechanics B %P 132-143 %R doi:10.1016/j.euromechflu.2018.04.003 %T The turbulent airflow over wind generated surface waves %U https://doi.org/10.1016/j.euromechflu.2018.04.003 %X The airflow dynamics above the air–sea interface are believed to have a significant impact on the fluxes of momentum and scalars across the ocean surface. We present an experimental study of the turbulent structure of the airflow above wind generated surface waves. Measurements, taken at a fetch of 22.7 m in University of Delaware’s large wind-wave–current facility, are reported for wind wave experiments with 10-m extrapolated wind speeds spanning from 2.19 m s−1 to 16.63 m s−1. In order to complete this study, we developed a complex imaging system, combining particle image velocimetry with laser induced fluorescence techniques. High resolution two-dimensional (18.7 cm x 9.7 cm) velocity fields were measured as close as 100 m above the air–water interface (on average). In addition, we acquired high spatial and temporal resolution wave field data simultaneously with the airflow measurements. Using this imaging system, we were able to perform phase averaging and separate the turbulent, mean and wave-induced velocity fields. We observe direct evidence of airflow separation events past the crests of wind waves, starting at low to moderate wind speeds ( m s−1). In general, the turbulent boundary layer in the air is characterized by numerous velocity sweeps and ejections, accompanied by intense downwind-tilted spanwise vorticity (shear) layers stemming from the surface. We were able to directly observe these turbulent events, and estimate their statistical significance using quadrant analysis. These events become phase-locked in the presence of waves, and, when m s−1, they are accompanied by intermittent airflow separation events past wave crests. The production of TKE also shows wave phase locked features indicating that further analysis of the wave-coherent contributions to the TKE balance is needed. %0 journal article %@ 2296-7745 %A Meier, H.E.M., Edman, M., Eilola, K., Placke, M., Neumann, T., Andersson, H.C., Brunnabend, S.-E., Dieterich, C., Frauen, C., Friedland, R., Groeger, M., Gustafsson, B.G., Gustafsson, E., Isaev, A., Kniebusch, M., Kuznetsov, I., Mueller-Karulis, B., Naumann, M., Omstedt, A., Ryabchenko, V., Saraiva, S., Savchuk, O.P. %D 2019 %J Frontiers in Marine Science %P 46 %R doi:10.3389/fmars.2019.00046 %T Assessment of Uncertainties in Scenario Simulations of Biogeochemical Cycles in the Baltic Sea %U https://doi.org/10.3389/fmars.2019.00046 %X Following earlier regional assessment studies, such as the Assessment of Climate Change for the Baltic Sea Basin and the North Sea Region Climate Change Assessment, knowledge acquired from available literature about future scenario simulations of biogeochemical cycles in the Baltic Sea and their uncertainties is assessed. The identification and reduction of uncertainties of scenario simulations are issues for marine management. For instance, it is important to know whether nutrient load abatement will meet its objectives of restored water quality status in future climate or whether additional measures are required. However, uncertainties are large and their sources need to be understood to draw conclusions about the effectiveness of measures. The assessment of sources of uncertainties in projections of biogeochemical cycles based on authors' own expert judgment suggests that the biggest uncertainties are caused by (1) unknown current and future bioavailable nutrient loads from land and atmosphere, (2) the experimental setup (including the spin up strategy), (3) differences between the projections of global and regional climate models, in particular, with respect to the global mean sea level rise and regional water cycle, (4) differing model-specific responses of the simulated biogeochemical cycles to long-term changes in external nutrient loads and climate of the Baltic Sea region, and (5) unknown future greenhouse gas emissions. Regular assessments of the models' skill (or quality compared to observations) for the Baltic Sea region and the spread in scenario simulations (differences among projected changes) as well as improvement of dynamical downscaling methods are recommended. %0 conference lecture %@ %A Stresser, M., Horstmann, J. %D 2019 %J 12th Current, Waves and Turbulence Measurement, CWTMA 2019 %T Remote Quantification of Nearshore Wave Energy Dissipation Rates from Coherent X-band Radar Backscatter %U %X %0 journal article %@ 0278-4343 %A Zhao, C., Maerz, J., Hofmeister, R., Röttgers, R., Wirtz, K., Riethmüller, R., Schrum, C. %D 2019 %J Continental Shelf Research %P 127-146 %R doi:10.1016/j.csr.2019.01.012 %T Characterizing the vertical distribution of chlorophyll a in the German Bight %U https://doi.org/10.1016/j.csr.2019.01.012 %X Coastal and shelf seas display strong variability in the horizontal and vertical distributions of chlorophyll a (CHL). Detailed data are required to identify the processes that drive the observed spatio-temporal dynamics. A high-resolution, vertically resolved transect data set for biogeochemical and physical properties was collected in the inner German Bight (GB) from 2009 to 2011 on a seasonal basis. We used fluorescence as an indicator for phytoplankton biomass via the CHL concentrations. We classified profiles into different types by evaluating the heterogeneity of CHL vertical distribution and identifying vertical location (upper mixed layer, subsurface layer, bottom mixed layer of water column) of high CHL concentration in each profile. We analyzed the spatio-temporal occurrences of the different CHL vertical distribution types in the context of the hydrodynamic environment. More than half (68.7%) of all profiles showed vertically homogeneous CHL distributions. A smaller subset (3.2%) of all profiles showed subsurface CHL maximum layers (SCMLs) in the vicinity of the pycnocline, co-varying with strongly stratified conditions in deeper water. Profiles with highest concentration of CHL in the upper part of the water column (HCU) were observed in 11.5% of all profiles. Profiles with highest concentrations of CHL in the lower part of the water column (HCL) comprised 16.6% of all profiles. HCL profiles were extensively observed during the decay phase of the spring bloom and were associated with resuspension and erosion from pre-existing SCMLs, which could be driven by tide; photosynthetic activity below the pycnocline could also contribute. Under moderate weather conditions, tidal currents were the main driver of resuspension. This study highlighted the occurrence of SCMLs and HCL patterns in vertical CHL profiles in shallow shelf seas, such as the GB. %0 journal article %@ 2296-7745 %A Wollschlaeger, J., Roettgers, R., Petersen, W., Zielinski, O. %D 2019 %J Frontiers in Marine Science %P 534 %R doi:10.3389/fmars.2018.00534 %T Stick or Dye: Evaluating a Solid Standard Calibration Approach for Point-Source Integrating Cavity Absorption Meters (PSICAM) %U https://doi.org/10.3389/fmars.2018.00534 %X Together with scattering, the process of absorption determines the propagation of light within the water column. It is influenced by the concentration and composition of optically active substances (phytoplankton, chromophoric-dissolved organic matter, and non-living particles). For this reason, the absorption coefficients of a water sample can provide corresponding information. However, the accurate determination of absorption coefficients in natural waters is often difficult due to the usually low concentration of absorbing material and the errors that scattering on particles introduce in the measurements. These problems can be overcome by instruments based on integrating cavities like the point-source integrating-cavity absorption meter (PSICAM). The accuracy of PSICAM measurements is to a large degree related to the accuracy of the measurement of the reflectivity inside its cavity, as this determines its mean optical path length. A reflectivity measurement (“calibration”) is usually carried out by measuring a liquid dye (nigrosin) with known absorption coefficients, followed by bleaching and rinsing of the cavity. The procedure requires additional equipment like spectrophotometers and handling of a liquid standard. Therefore, it might be difficult or at least non-convenient under field conditions and is additionally a major obstacle for a potential automation of these systems. In the present study, an alternative calibration approach for a PSICAM is evaluated, taking advantage of a solid standard. The standard is characterized and its suitability for calibration is compared to that of a conventional, nigrosin-based reflectivity measurement. Furthermore, the application in an automated flow-through PSICAM system (HyAbS) used in the field is tested. The results show that the performance of the solid standard calibration is comparable to that of the nigrosine-based calibration. Furthermore, it improves the measurements of the automated system. Thus, due to its simplicity, the solid standard calibration might foster the use of PSICAM systems, which allow a more accurate determination of absorption coefficients in natural water samples compared to conventional spectrophotometric techniques. Furthermore, it will potentially facilitate further approaches to automate these instruments. %0 book part %@ %A Wollschlaeger, J., Möller, K.O. %D 2019 %J Challenges and Innovations in Ocean In Situ Sensors - Measuring Inner Ocean Processes and Health in the Digital Age %P 81-94 %R doi:10.1016/B978-0-12-809886-8.00003-X %T Ocean In Situ Sensors: New Developments in Biological Sensors - Plankton Needs and Methods %U https://doi.org/10.1016/B978-0-12-809886-8.00003-X %X The term plankton describes all water-living organisms whose inherent movement abilities are small compared to the movement of the surrounding water. Strictly speaking, this includes also comprehensively large organisms like jellyfish, but most planktonic organisms are of relatively small size (micrometers to millimeters). Phytoplankton as the “plant” part of the plankton community comprises a large variety of photosynthetic active organisms, both prokaryotic and eukaryotic, which as primary producers transforming inorganic carbon into biomass using light as source of energy. Although they constitute only 1% of global primary producer biomass, these organisms are responsible for approx. 50 % of global carbon fixation and oxygen production (Field et al., 1998) and, hence, mediate carbon flux from the atmosphere to the oceans. The heterotrophic zooplankton, the “animal” part of plankton, is in contrast the primary consumer of phytoplankton, and in turn a major food source for larger organisms. Thus, zooplankton links phytoplankton production to higher trophic levels (e.g. fish), which members can have a certain relevance for human economy and nutrition. In total, the plankton constitutes the basal levels of the aquatic food web, and due to this crucial ecological position, investigation and monitoring of its dynamics in terms of biomass and community structure is a topic of ongoing importance. Plankton populations can provide an indicator of the status of the marine environment (Devlin et al., 2007; Racault et al., 2014). Thus, especially in the light of climate change, ocean acidification, introduction of foreign species, and various types of pollution due to human activities, potential changes in the plankton have to be detected and evaluated to estimate potential consequences for marine ecosystem services. %0 journal article %@ 1991-959X %A Hordoir, R., Axell, L., Hoeglung, A., Dieterich, C., Fransner, F., Groeger, M., Liu, Y., Pemberton, P., Schimanke, S., Andersson, H., Ljungemyr, P., Nygren, P., Falahat, S., Nord, A., Joensson, A., Lake, I., Doeoes, K., Hieronymus, M., Dietze, H., Loeptien, U., Kuznetsov, I., Westerlund, A., Tuomi, L., Haapala, J. %D 2019 %J Geoscientific Model Development %N 1 %P 363-386 %R doi:10.5194/gmd-12-363-2019 %T Nemo-Nordic 1.0: A NEMO based ocean model for Baltic & North Seas, research and operational applications %U https://doi.org/10.5194/gmd-12-363-2019 1 %X We present Nemo-Nordic, a Baltic & North Sea model based on the NEMO ocean engine. Surrounded by highly industrialised countries, the Baltic and North seas, and their assets associated with shipping, fishing and tourism; are vulnerable to anthropogenic pressure and climate change. Ocean models providing reliable forecasts, and enabling climatic studies, are important tools for the shipping infrastructure and to get a better understanding of effects of climate change on the marine ecosystems. Nemo-Nordic is intended to come as a tool for both short term and long term simulations, and to be used for ocean forecasting as well as process and climatic studies. Here, the scientific and technical choices within Nemo-Nordic are introduced, and the reasons behind the design of the model and its domain, and the inclusions of the two seas, are explained. The model's ability to represent barotropic and baroclinic dynamics, as well as the vertical structure of the water column, is presented. Biases are shown and discussed. The short term capabilities of the model are presented, and especially its capabilities to represent sea level on an hourly timescale with a high degree of accuracy. We also show that the model can represent longer time scale, with a focus on the Major Baltic Inflows and the variability of deep water salinity in the Baltic Sea. %0 book part %@ %A Petersen, W. %D 2019 %J Challenges and Innovations in Ocean In Situ Sensors - Measuring Inner Ocean Processes and Health in the Digital Age %P 194-205 %R doi:10.1016/B978-0-12-809886-8.00005-3 %T Innovative Sensor Carriers for Cost-Effective Global Ocean Samplings - Platforms of opportunity in action: The FerryBox system %U https://doi.org/10.1016/B978-0-12-809886-8.00005-3 %X FerryBox systems are newly developed instrument for automatic measurements of a series of environmental oceanographic parameters to support monitoring of the water quality of coastal and offshore waters. The principal idea of the FerryBox is to use ships of opportunity like ferries or other commercial ships on fixed routes to make high-frequent repeated automatic measurements of important oceanographic parameters. Measurements are made in a flow-through system where different sensors are applied to measure continuously different parameters. The sustainability of the systems for long-term unattended measurement can be enhanced by using automatic cleaning systems so that maintenance can be significantly reduced. Basic FerryBox systems are equipped with sensors for measuring seawater temperature, salinity, turbidity, and chlorophyll-a fluorescence as a measure of the amount of algae. The systems can be extended with other sensors for e.g. the carbon cycle (pH, pCO2, alkalinity), algal composition as well as nutrients like phosphate, nitrate and silicate. After an initial impulse by an European funded project FerryBox systems are more and more used by different European agencies as well as research institutes. %0 journal article %@ 0739-0572 %A Merckelbach, L., Berger, A., Krahmann, G., Dengler, M., Carpenter, J.R. %D 2019 %J Journal of Atmospheric and Oceanic Technology %N 2 %P 281-296 %R doi:10.1175/JTECH-D-18-0168.1 %T A Dynamic Flight Model for Slocum Gliders and Implications for Turbulence Microstructure Measurements %U https://doi.org/10.1175/JTECH-D-18-0168.1 2 %X The turbulent dissipation rate ɛ is a key parameter to many oceanographic processes. Recently gliders have been increasingly used as a carrier for microstructure sensors. Compared to conventional ship-based methods, glider-based microstructure observations allow for long duration measurements under adverse weather conditions, and at lower costs. The incident water velocity U is an input parameter for the calculation of the dissipation rate. Since U can not be measured using the standard glider sensor setup, the parameter is normally computed from a steady-state glider flight model. As ɛ scales with U2 or U4, depending whether it is computed from temperature or shear microstructure, flight model errors can introduce a significant bias. This study is the first to use measurements of in-situ glider flight, obtained with a profiling Doppler velocity log and an electromagnetic current meter, to test and calibrate a flight model, extended to include inertial terms. Compared to a previously suggested flight model, the calibrated model removes a bias of approximately 1 cm s−1 in the incident water velocity, which translates to roughly a factor of 1.2 in estimates of the dissipation rate. The results further indicate that 90% of the estimates of the dissipation rate from the calibrated model are within a factor of 1.1 and 1.2 for measurements derived from microstructure temperature sensors and shear probes, respectively. We further outline the range of applicability of the flight model. %0 journal article %@ 1991-959X %A Androsov, A., Fofonova, V., Kuznetsov, I., Danilov, S., Rakowsky, N., Harig, S., Brix, H., Wiltshire, K.H. %D 2019 %J Geoscientific Model Development %N 3 %P 1009-1028 %R doi:10.5194/gmd-12-1009-2019 %T FESOM-C v.2: coastal dynamics on hybrid unstructured meshes %U https://doi.org/10.5194/gmd-12-1009-2019 3 %X We describe FESOM-C, the coastal branch of the Finite-volumE Sea ice -- Ocean Model (FESOM2), which shares with FESOM2 many numerical aspects, in particular, its finite-volume cell-vertex discretization. Its dynamical core differs by the implementation of time stepping, the use of terrain-following vertical coordinate and formulation for hybrid meshes composed of triangles and quads. The first two distinctions were critical for coding FESOM-C as an independent branch. The hybrid mesh capability improves numerical efficiency, since quadrilateral cells have fewer edges than triangular cells. They do not suffer from spurious inertial modes of the triangular cell-vertex discretization and need less dissipation. The hybrid mesh capability allows one to use quasi-quadrilateral unstructured meshes, with triangular cells included only to join quadrilateral patches of differt resolution or instead of strongly deformed quadrilateral cells. The description of the model numerical part is complemented by test cases illustrating the model performance. %0 journal article %@ 2072-4292 %A Liu, Y., Boss, E., Chase, A., Xi, H., Zhang, X., Roettgers, R., Pan, Y., Bracher, A. %D 2019 %J Remote Sensing %N 3 %P 318 %R doi:10.3390/rs11030318 %T Retrieval of Phytoplankton Pigments from Underway Spectrophotometry in the Fram Strait %U https://doi.org/10.3390/rs11030318 3 %X Phytoplankton in the ocean are extremely diverse. The abundance of various intracellular pigments are often used to study phytoplankton physiology and ecology, and identify and quantify different phytoplankton groups. In this study, phytoplankton absorption spectra ( aph(λ) ) derived from underway flow-through AC-S measurements in the Fram Strait are combined with phytoplankton pigment measurements analyzed by high-performance liquid chromatography (HPLC) to evaluate the retrieval of various pigment concentrations at high spatial resolution. The performances of two approaches, Gaussian decomposition and the matrix inversion technique are investigated and compared. Our study is the first to apply the matrix inversion technique to underway spectrophotometry data. We find that Gaussian decomposition provides good estimates (median absolute percentage error, MPE 21–34%) of total chlorophyll-a (TChl-a), total chlorophyll-b (TChl-b), the combination of chlorophyll-c1 and -c2 (Chl-c1/2), photoprotective (PPC) and photosynthetic carotenoids (PSC). This method outperformed one of the matrix inversion algorithms, i.e., singular value decomposition combined with non-negative least squares (SVD-NNLS), in retrieving TChl-b, Chl-c1/2, PSC, and PPC. However, SVD-NNLS enables robust retrievals of specific carotenoids (MPE 37–65%), i.e., fucoxanthin, diadinoxanthin and 19 ′ -hexanoyloxyfucoxanthin, which is currently not accomplished by Gaussian decomposition. More robust predictions are obtained using the Gaussian decomposition method when the observed aph(λ) is normalized by the package effect index at 675 nm. The latter is determined as a function of “packaged” aph(675) and TChl-a concentration, which shows potential for improving pigment retrieval accuracy by the combined use of aph(λ) and TChl-a concentration data. To generate robust estimation statistics for the matrix inversion technique, we combine leave-one-out cross-validation with data perturbations. We find that both approaches provide useful information on pigment distributions, and hence, phytoplankton community composition indicators, at a spatial resolution much finer than that can be achieved with discrete samples. %0 journal article %@ 0079-6611 %A Schartau, M., Riethmueller, R., Floeser, G., Beusekom, J.E.E.van, Krasemann, H., Hofmeister, R., Wirtz, K. %D 2019 %J Progress in Oceanography %P 231-250 %R doi:10.1016/j.pocean.2018.12.011 %T On the separation between inorganic and organic fractions of suspended matter in a marine coastal environment %U https://doi.org/10.1016/j.pocean.2018.12.011 %X A central aspect of coastal biogeochemistry is to determine how nutrients, lithogenic and organic matter are distributed and transformed within coastal and estuarine environments. Analyses of the spatio-temporal changes of total suspended matter (TSM) concentration indicate strong and variable linkages between intertidal fringes and pelagic regions. In particular, knowledge about the organic fraction of TSM provides insight to how biogenic and lithogenic particulate matter are distributed in suspension. In our study we take advantage of a set of over 3000 in situ Loss on Ignition (LoI) data from the Southern North Sea that represent fractions of particulate organic matter (POM) relative to TSM (LoI POM:TSM). We introduce a parameterization (POM-TSM model) that distinguishes between two POM fractions incorporated in TSM. One fraction is described in association with mineral particles. The other represents a seasonally varying fresh pool of POM. The performance of the POM-TSM model is tested against data derived from MERIS/ENVISAT-TSM products of the German Bight. Our analysis of remote sensing data exhibits specific qualitative features of TSM that can be attributed to distinct coastal zones. Most interestingly, a transition zone between the Wadden Sea and seasonally stratified regions of the Southern North Sea is identified where mineral associated POM appears in concentrations comparable to those of freshly produced POM. We will discuss how this transition is indicative for a zone of effective particle interaction and sedimentation.The dimension of this transition zone varies between seasons and with location. Our proposed POM-TSM model is generic and can be calibrated against in situ data of other coastal regions. %0 journal article %@ 0024-3590 %A Voynova, Y.G., Petersen, W., Gehrung, M., Assmann, S., King, A.L. %D 2019 %J Limnology and Oceanography %N 3 %P 1135-1149 %R doi:10.1002/lno.11103 %T Intertidal regions changing coastal alkalinity: The Wadden Sea‐North Sea tidally coupled bioreactor %U https://doi.org/10.1002/lno.11103 3 %X In this study, we successfully implemented a total alkalinity (TA) analyzer in a flow‐through setup, in combination with a FerryBox. The high‐frequency (10 min) measurements along our ship's route revealed that in coastal systems, where carbon fluxes are dynamic, TA can differ significantly (by up to 100 μmol kg−1) between the nearshore and adjacent coastal regions. Even though this study could not account for the net yearly TA production in the coastal region, it demonstrated that there was a seasonal increase in TA of 100–150 μmol kg−1 in coastal waters of the North Sea, equivalent to TA production of 11.7–26.8 mmol m−2 d−1 during the spring and summer months. This seasonal change could not be accounted for by riverine contributions, but instead was probably related to seasonal organic matter production and processing in coastal and nearshore regions. Bottom sediments and the tidally coupled biogeochemical reactor between coastal (North Sea) and nearshore (Wadden Sea) regions are mediating this TA change, and the ~ 4 months lag between the seasonal increase in alkalinity and the peak organic matter production could be explained by the supply of (labile) organic matter and its temperature‐dependent remineralization via both aerobic and anaerobic pathways. %0 journal article %@ 0094-8276 %A Mellon, S., Kienast, M., Algar, C., Menocal, P., Kienast, S., Marchitto, T., Moros, M., Thomas, H. %D 2019 %J Geophysical Research Letters %N 24 %P 14683-14691 %R doi:10.1029/2019GL084965 %T Foraminifera Trace Anthropogenic CO2 in the NW Atlantic by 1950 %U https://doi.org/10.1029/2019GL084965 24 %X The Northwest Atlantic is a region of major climate change over the twentieth century, affected by the weakening of the Atlantic meridional overturning circulation. To assess whether the ability of this region to absorb anthropogenic CO2 has been impacted by this change, we present the region's first long‐term carbon isotope (δ13C) time series of fossil foraminifera spanning the past 4,000 years. These records reveal an unprecedented negative δ13C excursion driven by anthropogenic CO2 penetration into the surface ocean, the “Suess effect” signal. This signal (amplitude −0.45‰) emerges in 1950 CE ± 15 with a decrease rate of 0.009 ± 0.001‰/yr. This marine signal is ~30% of the atmospheric Suess effect and emerges over a century later. Based on current estimates of the ratio of δ13CDIC change to dissolved inorganic carbon change and limited constraints on surface ocean residence times, we calculate a mean anthropogenic CO2 uptake rate of 0.6 ± 0.2 μmol/(kg yr) from 1950 to 2005. %0 journal article %@ 0022-3670 %A Napolitano, D., Silveira, I., Rocha, C., Flierl, G., Calil, P., Martins, R. %D 2019 %J Journal of Physical Oceanography %N 12 %P 3127-3143 %R doi:10.1175/JPO-D-19-0011.1 %T On the Steadiness and Instability of the Intermediate Western Boundary Current between 24° and 18°S %U https://doi.org/10.1175/JPO-D-19-0011.1 12 %X scatter diagram also shows that the IWBC is potentially unstable. Further analysis of the ROMS simulation reveals that remotely generated, westward-propagating nonlinear eddies are the main source of variability in the region. These eddies enter the domain through the Tubarão Bight eastern edge and strongly interact with the IWBC. As they are advected downstream and negotiate the local topography, the eddies grow explosively through horizontal shear production. %0 journal article %@ 2296-6463 %A König, M., Hieronymi, M., Oppelt, N. %D 2019 %J Frontiers in Earth Science %P 22 %R doi:10.3389/feart.2019.00022 %T Application of Sentinel-2 MSI in Arctic Research: Evaluating the Performance of Atmospheric Correction Approaches Over Arctic Sea Ice %U https://doi.org/10.3389/feart.2019.00022 %X Multispectral remote sensing may be a powerful tool for areal retrieval of biogeophysical parameters in the Arctic sea ice. The MultiSpectral Instrument on board the Sentinel-2 (S-2) satellites of the European Space Agency offers new possibilities for Arctic research; S-2A and S-2B provide 13 spectral bands between 443 and 2,202 nm and spatial resolutions between 10 and 60 m, which may enable the monitoring of large areas of Arctic sea ice. For an accurate retrieval of parameters such as surface albedo, the elimination of atmospheric influences in the data is essential. We therefore provide an evaluation of five currently available atmospheric correction processors for S-2 (ACOLITE, ATCOR, iCOR, Polymer, and Sen2Cor). We evaluate the results of the different processors using in situ spectral measurements of ice and snow and open water gathered north of Svalbard during RV Polarstern cruise PS106.1 in summer 2017. We used spectral shapes to assess performance for ice and snow surfaces. For open water, we additionally evaluated intensities. ACOLITE, ATCOR, and iCOR performed well over sea ice and Polymer generated the best results over open water. ATCOR, iCOR and Sen2Cor failed in the image-based retrieval of atmospheric parameters (aerosol optical thickness, water vapor). ACOLITE estimated AOT within the uncertainty range of AERONET measurements. Parameterization based on external data, therefore, was necessary to obtain reliable results. To illustrate consequences of processor selection on secondary products we computed average surface reflectance of six bands and normalized difference melt index (NDMI) on an image subset. Medians of average reflectance and NDMI range from 0.80–0.97 to 0.12–0.18 while medians for TOA are 0.75 and 0.06, respectively. %0 journal article %@ 0169-3298 %A Giardino, C. Brando, V., Gege, P., Pinnel, N., Hochberg, E., Knaeps, E., Reusen, I., Doerffer, R., Bresciani, M., Braga, F., Foerster, S., Champollion, N., Dekker, A. %D 2019 %J Surveys in Geophysics %N 3 %P 401-429 %R doi:10.1007/s10712-018-9476-0 %T Imaging Spectrometry of Inland and Coastal Waters: State of the Art, Achievements and Perspectives %U https://doi.org/10.1007/s10712-018-9476-0 3 %X Imaging spectrometry of non-oceanic aquatic ecosystems has been in development since the late 1980s when the first airborne hyperspectral sensors were deployed over lakes. Most water quality management applications were, however, developed using multispectral mid-spatial resolution satellites or coarse spatial resolution ocean colour satellites till now. This situation is about to change with a suite of upcoming imaging spectrometers being deployed from experimental satellites or from the International Space Station. We review the science of developing applications for inland and coastal aquatic ecosystems that often are a mixture of optically shallow and optically deep waters, with gradients of clear to turbid and oligotrophic to hypertrophic productive waters and with varying bottom visibility with and without macrophytes, macro-algae, benthic micro-algae or corals. As the spaceborne, airborne and in situ optical sensors become increasingly available and appropriate for aquatic ecosystem detection, monitoring and assessment, the science-based applications will need to be further developed to an operational level. The Earth Observation-derived information products will range from more accurate estimates of turbidity and transparency measures, chlorophyll, suspended matter and coloured dissolved organic matter concentration, to more sophisticated products such as particle size distributions, phytoplankton functional types or distinguishing sources of suspended and coloured dissolved matter, estimating water depth and mapping types of heterogeneous substrates. We provide an overview of past science, current state of the art and future directions so that early career scientists as well as aquatic ecosystem managers and associated industry groups may be prepared for the imminent deluge of imaging spectrometry data. %0 journal article %@ 2045-2322 %A Kitidis, V., Shutler, J., Ashton, I., Warren, M., Brown, I., Findlay, H., Hartman, S., Sanders, R., Humphreys, M., Kivimäe, C., Greenwood, N., Hull, T., Pearce, D., Petersen, W., Voynova, Y., Chapron, B., Grouazel, A., Land, P., Sharples, J., Nightingale, P. %D 2019 %J Scientific Reports %P 20153 %R doi:10.1038/s41598-019-56363-5 %T Winter weather controls net influx of atmospheric CO2 on the north-west European shelf %U https://doi.org/10.1038/s41598-019-56363-5 %X Shelf seas play an important role in the global carbon cycle, absorbing atmospheric carbon dioxide (CO2) and exporting carbon (C) to the open ocean and sediments. The magnitude of these processes is poorly constrained, because observations are typically interpolated over multiple years. Here, we used 298500 observations of CO2 fugacity (fCO2) from a single year (2015), to estimate the net influx of atmospheric CO2 as 26.2 ± 4.7 Tg C yr−1 over the open NW European shelf. CO2 influx from the atmosphere was dominated by influx during winter as a consequence of high winds, despite a smaller, thermally-driven, air-sea fCO2 gradient compared to the larger, biologically-driven summer gradient. In order to understand this climate regulation service, we constructed a carbon-budget supplemented by data from the literature, where the NW European shelf is treated as a box with carbon entering and leaving the box. This budget showed that net C-burial was a small sink of 1.3 ± 3.1 Tg C yr−1, while CO2 efflux from estuaries to the atmosphere, removed the majority of river C-inputs. In contrast, the input from the Baltic Sea likely contributes to net export via the continental shelf pump and advection (34.4 ± 6.0 Tg C yr−1). %0 journal article %@ 1042-8275 %A Nyman, L., Lund, B., Graber, H., Romeiser, R., Horstmann, J. %D 2019 %J Oceanography %N 4 %P 175-183 %R doi:10.5670/oceanog.2019.423 %T Radar Observations of Ocean Surface Features Resulting from Underwater Topography Changes %U https://doi.org/10.5670/oceanog.2019.423 4 %X The near-surface response to underwater topography changes is of great importance for navigational safety near regions of strong bathymetry gradients, such as around the islands of the Republic of Palau. There, mean underwater inclines can be as much as 25% of the horizontal distance, leading to a depth change of up to 85% within 26 km. Many processes associated with oceanic flows produce surface manifestations that are readily imaged from afar by synthetic aperture radar (SAR) or ship-based X-band Doppler marine radar (DMR). SAR and DMR imagery complement each other, with SAR providing a large-scale snapshot of the region on the order of 50 km or more and the DMR offering a mobile smaller-scale look at a particular area on the order of about 6 km with the ability to measure near-surface currents (1–5 m depth) in the vicinity of the ship. In this paper, we discuss the results from an analysis of thousands of DMR images around the islands of Palau. Three types of ocean surface features were identified: internal waves, surface slicks, and convergent fronts. Internal waves and convergent fronts are directly influenced by abrupt topography, and surface slicks can aid in the surface feature imaging process if their shapes are modulated by spatially varying surface currents. These ocean surface features are examined with respect to their associations with changes in the seafloor thousands of meters beneath them. %0 journal article %@ 1471-2962 %A Filipot, J., Guimarães, P., Leckler, F., Horstmann, J., Carrasco, R., Leroy, E., Fady, N., Accensi, M., Prevosto, M., Duarte, R., Roeber, V., Benetazzo, A., Raoult, C., Franzetti, M., Varing, A., Le Dantec, N. %D 2019 %J Philosophical transactions of the Royal Society %N 2155 %P 20190008 %R doi:10.1098/rsta.2019.0008 %T La Jument lighthouse: a real-scale laboratory for the study of giant waves and their loading on marine structures %U https://doi.org/10.1098/rsta.2019.0008 2155 %X This paper presents results from an experiment designed to improve the understanding of the relationship between extreme breaking waves and their mechanical loading on heritage offshore lighthouses. The experiment, conducted at La Jument, an iconic French offshore lighthouse, featured several records of wave, current and structure accelerations acquired during severe storm conditions, with individual waves as high as 24 m. Data analysis focuses on a storm event marked by a strong peak in the horizontal accelerations measured inside La Jument. Thanks to stereo-video wave measurements synchronized to the acceleration record we were able to identify and describe the breaking wave responsible for this intense loading. Our observations suggest that this giant wave (19 m high) had a crest elevation high enough to directly hit the lighthouse tower, above the substructure. This paper reveals the potential for conducting ambitious field experiments from offshore lighthouses in order to collect valuable storm waves and wave loading observations. This offers a possible second service life for these heritage structures as in situ laboratories dedicated to the study of the coastal hydrodynamics and its interaction with marine structures. %0 conference paper %@ %A Stresser, M., Horstmann, J. %D 2019 %J 2019 IEEE/OES Twelfth Current, Waves and Turbulence Measurement (CWTM) %P 1-6 %R doi:10.1109/CWTM43797.2019.8955284 %T Remote Quantification of Nearshore Wave Energy Dissipation Rates from Coherent X-Band Radar Backscatter %U https://doi.org/10.1109/CWTM43797.2019.8955284 %X We present an efficient, new methodology to remotely estimate nearshore wave energy dissipation using a shore based coherent-on-receive marine radar (CMR). The CMR measures the backscatter intensity as well as the Doppler shift velocity from the sea surface scattering. We show by comparisons to simulations that the spatial difference of the Doppler velocity is related to local roller dissipation rates. From the spatial distribution of the radar derived dissipation, the offshore significant wave height can be estimated with a root-mean-square error of 23 cm with bias of 4 cm when compared to a moored wave rider buoy at a distance of 1.1 km from the shore line. %0 report %@ 1098-603 %A Boss, E., Brewin, R., Bulgarelli, B., Chauhan, P., Doerffer, R., Dutkiewicz, S., Ford, D., Franz, B., Frouin, R., Hieronymi, M., Hu, C., Hunt, S., Jackson, T., Jay, S., Jolivet, D., Jones, E.E., Kobayashi, H., Kwiatkowska, E., Lamquin, N., Lavender, S., Maritorena, S., Martinez-Vicent, V., McKinna, L. %D 2019 %J %R doi:10.25607/OBP-696 %T Uncertainties in Ocean Colour Remote Sensing %U https://doi.org/10.25607/OBP-696 %X This report on "Uncertainties in Ocean Colour Remote Sensing" summarizes the state of the knowledge on uncertainties related to ocean colour (OC) products and identifies ideas and recommendations to achieve significant progress on how uncertainties are quantified and distributed. The report starts with a presentation of terminology and concepts (Chapter 2). For a proper use of OC data, it is necessary to be aware of the potential problems and limitations associated with OC remote sensing products, and to identify the sources contributing to their uncertainties, from top-of-atmosphere (TOA) data to gridded products. This report makes a review of these factors (Chapter 3). Even though up to now very few OC products have been distributed with uncertainty estimates, a number of approaches to quantify OC product uncertainties have been proposed in recent years; providing a review of these methods and discussing their respective advantages appear particularly timely (Chapter 4). It is also ..... %0 journal article %@ 0022-3670 %A Husain, N., Hara, T., Buckley, M., Yousefi, K., Veron, F., Sullivan, P. %D 2019 %J Journal of Physical Oceanography %N 8 %P 1997-2015 %R doi:10.1175/JPO-D-19-0070.1 %T Boundary Layer Turbulence over Surface Waves in a Strongly Forced Condition: LES and Observation %U https://doi.org/10.1175/JPO-D-19-0070.1 8 %X The impact of sea state on air–sea momentum flux (or wind stress) is a poorly understood component of wind–wave interactions, particularly in high wind conditions. The wind stress and mean wind profile over the ocean are influenced by the characteristics of boundary layer turbulence over surface waves, which are strongly modulated by transient airflow separation events; however, the features controlling their occurrence and intensity are not well known. A large-eddy simulation (LES) for wind over a sinusoidal wave train is employed to reproduce laboratory observations of phase-averaged airflow over waves in strongly forced conditions. The LES and observation both use a wave-following coordinate system with a decomposition of wind velocity into mean, wave-coherent, and turbulent fluctuation components. The LES results of the mean wind profile and structure of wave-induced and turbulent stress components agree reasonably well with observations. Both LES and observation show enhanced turbulent stress and mean wind shear at the height of the wave crest, signifying the impact of intermittent airflow separation events. Disparities exist particularly near the crest, suggesting that airflow separation and sheltering are affected by the nonlinearity and unsteadiness of laboratory waves. Our results also suggest that the intensity of airflow separation is most sensitive to wave steepness and the surface roughness parameterization near the crest. These results clarify how the characteristics of finite-amplitude waves can control the airflow dynamics, which may substantially influence the mean wind profile, equivalent surface roughness, and drag coefficient. %0 journal article %@ 1023-5809 %A Guha, A., Raj, R. %D 2019 %J Nonlinear Processes in Geophysics %N 3 %P 283-290 %R doi:10.5194/npg-26-283-2019 %T Explosive instability due to flow over a rippled bottom %U https://doi.org/10.5194/npg-26-283-2019 3 %X In this paper, we study Bragg resonance, i.e., the triad interaction between surface and/or interfacial waves with a bottom ripple, in the presence of background velocity. We show that when one of the constituent waves of the triad has negative energy, the amplitudes of all the waves grow exponentially. This is very different from classic Bragg resonance in which one wave decays to cause the growth of the other. The instabilities we observe are “explosive” and are different from normal mode shear instabilities since our velocity profiles are linearly stable. Our work may explain the existence of large-amplitude internal waves over periodic bottom ripples in the presence of tidal flow observed in oceans and estuaries. %0 journal article %@ 1424-8220 %A Sathyendranath, S., Brewin, R., Brockmann, C., Brotas, V., Calton, B., Chuprin, A., Cipollini, P., Couto, A., Dingle, J., Doerffer, R., Donlon, C., Dowell, M., Grant, M., Groom, S., Horseman, A., Jackson, T., Krasemann, H., Lavender, S., Martinez-Vicente, V., Mazeran, C., Melin, F., Moore, T., Müller, D., Regner, P., Roy, S., Steele, C., Steinmetz, F., Swinton, J., Taberner, M., Thompson, A., Valente, A., Zühlke, M., Brando, V., Feng, H., Feldman, G., Franz, B., Frouin, R., Gould, R., Hooker, S., Kahru, M., Kratzer, S., Mitchell, B., Muller-Karger, F., Sosik, H., Voss, K., Werdell, J., Platt, T. %D 2019 %J Sensors %N 19 %P 4285 %R doi:10.3390/s19194285 %T An Ocean-Colour Time Series for Use in Climate Studies: The Experience of the Ocean-Colour Climate Change Initiative (OC-CCI) %U https://doi.org/10.3390/s19194285 19 %X Ocean colour is recognised as an Essential Climate Variable (ECV) by the Global Climate Observing System (GCOS); and spectrally-resolved water-leaving radiances (or remote-sensing reflectances) in the visible domain, and chlorophyll-a concentration are identified as required ECV products. Time series of the products at the global scale and at high spatial resolution, derived from ocean-colour data, are key to studying the dynamics of phytoplankton at seasonal and inter-annual scales; their role in marine biogeochemistry; the global carbon cycle; the modulation of how phytoplankton distribute solar-induced heat in the upper layers of the ocean; and the response of the marine ecosystem to climate variability and change. However, generating a long time series of these products from ocean-colour data is not a trivial task: algorithms that are best suited for climate studies have to be selected from a number that are available for atmospheric correction of the satellite signal and for retrieval of chlorophyll-a concentration; since satellites have a finite life span, data from multiple sensors have to be merged to create a single time series, and any uncorrected inter-sensor biases could introduce artefacts in the series, e.g., different sensors monitor radiances at different wavebands such that producing a consistent time series of reflectances is not straightforward. Another requirement is that the products have to be validated against in situ observations. Furthermore, the uncertainties in the products have to be quantified, ideally on a pixel-by-pixel basis, to facilitate applications and interpretations that are consistent with the quality of the data. This paper outlines an approach that was adopted for generating an ocean-colour time series for climate studies, using data from the MERIS (MEdium spectral Resolution Imaging Spectrometer) sensor of the European Space Agency; the SeaWiFS (Sea-viewing Wide-Field-of-view Sensor) and MODIS-Aqua (Moderate-resolution Imaging Spectroradiometer-Aqua) sensors from the National Aeronautics and Space Administration (USA); and VIIRS (Visible and Infrared Imaging Radiometer Suite) from the National Oceanic and Atmospheric Administration (USA). The time series now covers the period from late 1997 to end of 2018. To ensure that the products meet, as well as possible, the requirements of the user community, marine-ecosystem modellers, and remote-sensing scientists were consulted at the outset on their immediate and longer-term requirements as well as on their expectations of ocean-colour data for use in climate research. Taking the user requirements into account, a series of objective criteria were established, against which available algorithms for processing ocean-colour data were evaluated and ranked. The algorithms that performed best with respect to the climate user requirements were selected to process data from the satellite sensors. Remote-sensing reflectance data from MODIS-Aqua, MERIS, and VIIRS were band-shifted to match the wavebands of SeaWiFS. Overlapping data were used to correct for mean biases between sensors at every pixel. The remote-sensing reflectance data derived from the sensors were merged, and the selected in-water algorithm was applied to the merged data to generate maps of chlorophyll concentration, inherent optical properties at SeaWiFS wavelengths, and the diffuse attenuation coefficient at 490 nm. The merged products were validated against in situ observations. The uncertainties established on the basis of comparisons with in situ data were combined with an optical classification of the remote-sensing reflectance data using a fuzzy-logic approach, and were used to generate uncertainties (root mean square difference and bias) for each product at each pixel. %0 journal article %@ 1726-4170 %A Horwitz, R., Hay, A., Burt, W., Cheel, R., Salisbury, J., Thomas, H. %D 2019 %J Biogeosciences %N 2 %P 605-616 %R doi:10.5194/bg-16-605-2019 %T High-frequency variability of CO2 in Grand Passage, Bay of Fundy, Nova Scotia %U https://doi.org/10.5194/bg-16-605-2019 2 %X Assessing changes in the marine carbon cycle arising from anthropogenic CO2 emissions requires a detailed understanding of the carbonate system's natural variability. Coastal ecosystems vary over short spatial and temporal scales, so their dynamics are not well described by long-term and broad regional averages. A year-long time series of pCO2, temperature, salinity, and currents is used to quantify the high-frequency variability of the carbonate system at the mouth of the Bay of Fundy, Nova Scotia. The seasonal cycle of pCO2 is modulated by a diel cycle that is larger in summer than in winter and a tidal contribution that is primarily M2, with amplitude roughly half that of the diel cycle throughout the year. The interaction between tidal currents and carbonate system variables leads to lateral transport by tidal pumping, which moves alkalinity and dissolved inorganic carbon (DIC) out of the bay, opposite to the mean flow in the region, and constitutes a new feature of how this strongly tidal region connects to the larger Gulf of Maine and northwest Atlantic carbon system. These results suggest that tidal pumping could substantially modulate the coastal ocean's response to global ocean acidification in any region with large tides and spatial variation in biological activity, requiring that high-frequency variability be accounted for in assessments of carbon budgets of coastal regions. %0 book part %@ 1385-7525 %A Giardino, C., Brando, V., Gege, P., Pinnel, N., Hochberg, E., Knaeps, E., Reusen, I., Doerffer, R., Bresciani, M., Braga, F., Foerster, S., Champollion, N., Dekker, A. %D 2019 %J Exploring the Earth System with Imaging Spectroscopy %P 105-134 %R doi:10.1007/s10712-018-9476-0 %T Imaging Spectrometry of Inland and Coastal Waters: State of the Art, Achievements and Perspectives %U https://doi.org/10.1007/s10712-018-9476-0 %X Imaging spectrometry of non-oceanic aquatic ecosystems has been in development since the late 1980s when the first airborne hyperspectral sensors were deployed over lakes. Most water quality management applications were, however, developed using multispectral mid-spatial resolution satellites or coarse spatial resolution ocean colour satellites till now. This situation is about to change with a suite of upcoming imaging spectrometers being deployed from experimental satellites or from the International Space Station. We review the science of developing applications for inland and coastal aquatic ecosystems that often are a mixture of optically shallow and optically deep waters, with gradients of clear to turbid and oligotrophic to hypertrophic productive waters and with varying bottom visibility with and without macrophytes, macro-algae, benthic micro-algae or corals. As the spaceborne, airborne and in situ optical sensors become increasingly available and appropriate for aquatic ecosystem detection, monitoring and assessment, the science-based applications will need to be further developed to an operational level. The Earth Observation-derived information products will range from more accurate estimates of turbidity and transparency measures, chlorophyll, suspended matter and coloured dissolved organic matter concentration, to more sophisticated products such as particle size distributions, phytoplankton functional types or distinguishing sources of suspended and coloured dissolved matter, estimating water depth and mapping types of heterogeneous substrates. We provide an overview of past science, current state of the art and future directions so that early career scientists as well as aquatic ecosystem managers and associated industry groups may be prepared for the imminent deluge of imaging spectrometry data. %0 journal article %@ 1094-4087 %A Hieronymi, M. %D 2019 %J Optics express %N 12 %P A 707-A 724 %R doi:10.1364/OE.27.00A707 %T Spectral band adaptation of ocean color sensors for applicability of the multi-water biogeo-optical algorithm ONNS %U https://doi.org/10.1364/OE.27.00A707 12 %X The ocean color algorithm ONNS (OLCI Neural Network Swarm) is designed to process remote-sensing reflectances at 11 Sentinel-3/OLCI bands in order to derive water quality parameters for most natural waters [Hieronymi et al., Front. Mar. Sci. 4, 140 (2017)]. The present work introduces a spectral band-shifting procedure, which allows exploitation of atmospherically corrected input from SeaWiFS, MODIS, MERIS, OCM-2, VIIRS, SGLI, GOCI-2, EnMAP, or PACE/OCI and corresponding utilization of ONNS or other ocean color algorithms. The performance of the band adapters is evaluated in view of diverse optical water types. In the spectral range between 400 and 600 nm, the mean percentage retrieval error is mostly <5%. The band adaptation is a tool for cross-mission Earth observation and uncertainty estimate, as well as for extended possibilities of algorithm validation. %0 journal article %@ 2296-7745 %A Todd, R.E., Chavez, F.P., Clayton, S., Cravatte, S., Goes, M., Graco, M., Lin, X., Sprintall, J., Zilberman, N.V., Archer, M., Arístegui, J., Balmaseda, M., Bane, J.M., Baringer, M.O., Barth, J.A., Beal, L.M., Brandt, P., Calil, P.H.R., Campos, E., Centurioni, L.R., Chidichimo, M.P., Cirano, M., Cronin, M.F., Curchitser, E.N., Davis, R.E., Dengler, M., deYoung, B., Dong, S., Escribano, R., Fassbender, A.J., Fawcett, S.E., Feng, M., Goni, G.J., Gray, A.R., Gutiérrez, D., Hebert, D., Hummels, R., Ito, S., Krug, M., Lacan, F., Laurindo, L., Lazar, A., Lee, C.M., Lengaigne, M., Levine, N.M., Middleton, J., Montes, I., Muglia, M., Nagai, T., Palevsky, H.I., Palter, J.B., Phillips, H.E., Piola, A., Plueddemann, A.J., Qiu, B., Rodrigues, R.R., Roughan, M., Rudnick, D.L., Rykaczewski, R.R., Saraceno, M., Seim, H., Gupta, A.S., Shannon, L., Sloyan, B.M., Sutton, A.J., Thompson, L., van der Plas, A.K., Volkov, D., Wilkin, J., Zhang, D., Zhang, L. %D 2019 %J Frontiers in Marine Science %P 423 %R doi:10.3389/fmars.2019.00423 %T Global Perspectives on Observing Ocean Boundary Current Systems %U https://doi.org/10.3389/fmars.2019.00423 %X Ocean boundary current systems are key components of the climate system, are home to highly productive ecosystems, and have numerous societal impacts. Establishment of a global network of boundary current observing systems is a critical part of ongoing development of the Global Ocean Observing System. The characteristics of boundary current systems are reviewed, focusing on scientific and societal motivations for sustained observing. Techniques currently used to observe boundary current systems are reviewed, followed by a census of the current state of boundary current observing systems globally. The next steps in the development of boundary current observing systems are considered, leading to several specific recommendations. %0 journal article %@ 2296-7745 %A Gonçalves-Araujo, R., Röttgers, R., Haraguchi, L., Brandini, F.P. %D 2019 %J Frontiers in Marine Science %P 716 %R doi:10.3389/fmars.2019.00716 %T Hydrography-driven variability of optically active constituents of water in the South Brazilian Bight: biogeochemical implications %U https://doi.org/10.3389/fmars.2019.00716 %X The South Brazilian Bight (SBB) is a hydrographically dynamic environment with strong seasonality that sustains a diverse planktonic community involved in diverse biogeochemical processes. The inherent optical properties (IOPs; e.g., absorption and scattering coefficients) of optically actives constituents of water (OACs; phytoplankton, non-algal particles–NAP, and colored dissolved organic matter–CDOM) have been widely employed to retrieve information on biogeochemical parameters in the water. In this study conducted in the SBB, a cross-shelf transect was performed for biogeochemistry and hydrographic sampling during a summer expedition. Our research aimed to determine the distribution and amount of the OACs based on their spectral signature, in relation to the distribution of water masses in the region. That allows us to get insights into the biogeochemical processes within each water mass and in the boundaries between them. We observed a strong intrusion of South Atlantic Central Water (SACW) over the shelf, mainly driven by the wind action. With that, phytoplankton development was fueled by the input of nutrients, and increased chlorophyll-a (Chl-a) concentrations were observed within the shallowest stations. Colored dissolved organic matter did not follow the distribution of dissolved organic carbon (DOC). Both CDOM and DOC presented high values at the low salinity Coastal Water (CW), as an indication of the continental influence over the shelf. However, CDOM was inversely correlated with salinity and lowest values were observed within Tropical Water (TW), whereas DOC values within TW were as high as within CW, indicating an autochthonous DOM source. Additionally, a deep Chl-a maximum (DCM) was noticed in the boundary between the TW and SACW. Along with the DCM, we observed the production of fresh, non-colored DOM attributed to the microbial community. Finally, our results suggest that CDOM is photodegraded at the surface of CW. This is mainly due to the Ekman transport effect over the region that traps CW at the surface, making it longer exposed to solar radiation. %0 journal article %@ 2296-7745 %A Roemmich, D., Alford, M.H., Claustre, H., Johnson, K.S., King, B., Moum, J., Oke, P.R., Owens, W.B., Pouliquen, S., Purkey, S., Scanderbeg, M., Suga, T., Wijffels, S.E., Zilberman, N., Bakker, D., Baringer, M.O., Belbeoch, M., Bittig, H.C., Boss, E., Calil, P., Carse, F., Carval, T., Chai, F., Conchubhair, D.O., D'Ortenzio, F., Dall'Olmo, G., Desbruyères, D., Fennel, K., Fer, I., Ferrari, R., Forget, G., Freeland, H., Fujiki, T., Gehlen, M., Greenan, B., Hallberg, R., Hibiya, T., Hosoda, S., Jayne, S., Jochum, M., Johnson, G.C., Kang, K.-R., Kolodziejczyk, N., Koertzinger, A., Le Traon, P.Y., Lenn, Y.-D., Maze, G., Mork, K.A., Morris, T., Nagai, T., Nash, J., Garabato, A.N., Olsen, A., Pattabhi, R.R., Prakash, S., Riser, S., Schmechtig, C., Shroyer, E., Sterl, A., Sutton, P., Talley, L., Tanhua, T., Thierry, V., Thomalla, S., Toole, J., Troisi, A., Trull, T., Turton, J.D., Velez-Belchi, P.J., Walczowski, W., Wang, H., Wanninkhof, R., Waterhouse, A., Watson, A., Wilson, C., Wong, A.P., Xu, J., Yasuda, I. %D 2019 %J Frontiers in Marine Science %P 439 %R doi:10.3389/fmars.2019.00439 %T On the Future of Argo: A Global, Full-Depth, Multi-Disciplinary Array %U https://doi.org/10.3389/fmars.2019.00439 %X The Argo Program has been implemented and sustained for almost two decades, as a global array of about 4000 profiling floats. Argo provides continuous observations of ocean temperature and salinity versus pressure, from the sea surface to 2000 dbar. The successful installation of the Argo array and its innovative data management system arose opportunistically from the combination of great scientific need and technological innovation. Through the data system, Argo provides fundamental physical observations with broad societally-valuable applications, built on the cost-efficient and robust technologies of autonomous profiling floats. Following recent advances in platform and sensor technologies, even greater opportunity exists now than 20 years ago to (i) improve Argo’s global coverage and value beyond the original design, (ii) extend Argo to span the full ocean depth, (iii) add biogeochemical sensors for improved understanding of oceanic cycles of carbon, nutrients, and ecosystems, and (iv) consider experimental sensors that might be included in the future, for example to document the spatial and temporal patterns of ocean mixing. For Core Argo and each of these enhancements, the past, present, and future progression along a path from experimental deployments to regional pilot arrays to global implementation is described. The objective is to create a fully global, top-to-bottom, dynamically complete, and multidisciplinary Argo Program that will integrate seamlessly with satellite and with other in situ elements of the Global Ocean Observing System (Legler et al., 2015). The integrated system will deliver operational reanalysis and forecasting capability, and assessment of the state and variability of the climate system with respect to physical, biogeochemical, and ecosystems parameters. It will enable basic research of unprecedented breadth and magnitude, and a wealth of ocean-education and outreach opportunities. %0 journal article %@ 2296-7745 %A Groom, S., Sathyendranath, S., Ban, Y., Bernard, S., Brewin, R., Brotas, V., Brockmann, C., Chauhan, P., Choi, J.-K., Chuprin, A., Ciavatta, S., Cipollini, P., Donlon, C., Franz, B., He, X., Hirata, T., Jackson, T., Kampel, M., Krasemann, H., Lavender, S., Pardo-Martinez, S., Melin, F., Platt, T., Santoleri, R., Skakala, J., Schaeffer, B., Smith, M., Steinmetz, F., Valente, A., Wang, M. %D 2019 %J Frontiers in Marine Science %P 485 %R doi:10.3389/fmars.2019.00485 %T Satellite Ocean Colour: Current Status and Future Perspective %U https://doi.org/10.3389/fmars.2019.00485 %X Spectrally resolved water-leaving radiances (ocean colour) and inferred chlorophyll concentration are key to studying phytoplankton dynamics at seasonal and inter-annual scales, for a better understanding of the role of phytoplankton in marine biogeochemistry; the global carbon cycle; and the response of marine ecosystems to climate variability, change and feedback processes. Ocean colour data also have a critical role in operational observation systems monitoring coastal eutrophication, harmful algal blooms, and sediment plumes. The contiguous ocean-colour record reached 21 years in 2018; however, it is comprised of a number of one-off missions such that creating a consistent time-series of ocean-colour data requires merging of the individual sensors (including MERIS, Aqua-MODIS, SeaWiFS, VIIRS, and OLCI) with differing sensor characteristics, without introducing artefacts. By contrast, the next decade will see consistent observations from operational ocean colour series with sensors of similar design and with a replacement strategy. Also, by 2029 the record will start to be of sufficient duration to discriminate climate change impacts from natural variability, at least in some regions. This paper describes the current status and future prospects in the field of ocean colour focusing on large to medium resolution observations of oceans and coastal seas. It reviews the user requirements in terms of products and uncertainty characteristics and then describes features of current and future satellite ocean-colour sensors, both operational and innovative. The key role of in situ validation and calibration is highlighted as are ground segments that process the data received from the ocean-colour sensors and deliver analysis-ready products to end-users. Example applications of the ocean-colour data are presented, focusing on the climate data record and operational applications including water quality and assimilation into numerical models. Current capacity building and training activities pertinent to ocean colour are described and finally a summary of future perspectives is provided. %0 journal article %@ 1070-6631 %A Carpenter, J.R., Guha, A. %D 2019 %J Physics of Fluids %N 8 %P 081701 %R doi:10.1063/1.5116633 %T Instability of a smooth shear layer through wave interactions %U https://doi.org/10.1063/1.5116633 8 %X We wish to acknowledge the support of the Helmholtz Association (PACES II) and the Alexander von Humboldt Foundation fellowship to A.G. We also thank Subhajit Kar for help and two anonymous reviewers for their insightful comments. %0 journal article %@ 2073-4441 %A Yakubov, S., Wallhead, P., Protsenko, E., Yakushev, E., Pakhomova, S., Brix, H. %D 2019 %J Water %N 8 %P 1582 %R doi:10.3390/w11081582 %T A 1-Dimensional Sympagic–Pelagic–Benthic Transport Model (SPBM): Coupled Simulation of Ice, Water Column, and Sediment Biogeochemistry, Suitable for Arctic Applications %U https://doi.org/10.3390/w11081582 8 %X Marine biogeochemical processes can strongly interact with processes occurring in adjacent ice and sediments. This is especially likely in areas with shallow water and frequent ice cover, both of which are common in the Arctic. Modeling tools are therefore required to simulate coupled biogeochemical systems in ice, water, and sediment domains. We developed a 1D sympagic–pelagic–benthic transport model (SPBM) which uses input from physical model simulations to describe hydrodynamics and ice growth and modules from the Framework for Aquatic Biogeochemical Models (FABM) to construct a user-defined biogeochemical model. SPBM coupled with a biogeochemical model simulates the processes of vertical diffusion, sinking/burial, and biogeochemical transformations within and between the three domains. The potential utility of SPBM is demonstrated herein with two test runs using modules from the European regional seas ecosystem model (ERSEM) and the bottom-redox model biogeochemistry (BROM-biogeochemistry). The first run simulates multiple phytoplankton functional groups inhabiting the ice and water domains, while the second simulates detailed redox biogeochemistry in the ice, water, and sediments. SPBM is a flexible tool for integrated simulation of ice, water, and sediment biogeochemistry, and as such may help in producing well-parameterized biogeochemical models for regions with strong sympagic–pelagic–benthic interactions. %0 journal article %@ 2072-4292 %A Ruddick, K.G., Voss, K., Banks, A.C., Boss, E., Castagna, A., Frouin, R., Hieronymi, M., Jamet, C., Johnson, B.C., Kuusk, J., Lee, Z., Ondrusek, M., Vabson, V., Vendt, R. %D 2019 %J Remote Sensing %N 15 %P 1742 %R doi:10.3390/rs11151742 %T A Review of Protocols for Fiducial Reference Measurements of Downwelling Irradiance for the Validation of Satellite Remote Sensing Data over Water %U https://doi.org/10.3390/rs11151742 15 %X This paper reviews the state of the art of protocols for the measurement of downwelling irradiance in the context of Fiducial Reference Measurements (FRM) of water reflectance for satellite validation. The measurement of water reflectance requires the measurement of water-leaving radiance and downwelling irradiance just above water. For the latter, there are four generic families of method, using: (1) an above-water upward-pointing irradiance sensor; (2) an above-water downward-pointing radiance sensor and a reflective plaque; (3) a Sun-pointing radiance sensor (sunphotometer); or (4) an underwater upward-pointing irradiance sensor deployed at different depths. Each method—except for the fourth, which is considered obsolete for the measurement of above-water downwelling irradiance—is described generically in the FRM context with reference to the measurement equation, documented implementations, and the intra-method diversity of deployment platform and practice. Ideal measurement conditions are stated, practical recommendations are provided on best practice, and guidelines for estimating the measurement uncertainty are provided for each protocol-related component of the measurement uncertainty budget. The state of the art for the measurement of downwelling irradiance is summarized, future perspectives are outlined, and key debates such as the use of reflectance plaques with calibrated or uncalibrated radiometers are presented. This review is based on the practice and studies of the aquatic optics community and the validation of water reflectance, but is also relevant to land radiation monitoring and the validation of satellite-derived land surface reflectance. %0 journal article %@ 1726-4170 %A Juhls, B., Overduin, P.P., Hoelemann, J., Hieronymi, M., Matsuoka, A., Heim, B., Fischer, J. %D 2019 %J Biogeosciences %N 13 %P 2693-2713 %R doi:10.5194/bg-16-2693-2019 %T Dissolved organic matter at the fluvial–marine transition in the Laptev Sea using in situ data and ocean colour remote sensing %U https://doi.org/10.5194/bg-16-2693-2019 13 %X River water is the main source of dissolved organic carbon (DOC) in the Arctic Ocean. DOC plays an important role in the Arctic carbon cycle and its export from land to sea is expected to increase as ongoing climate change accelerates permafrost thaw. However, transport pathways and transformation of DOC in the land-to-ocean transition are mostly unknown. We collected DOC and aCDOM(λ) samples from 11 expeditions to river, coastal and offshore waters and present a new DOC-aCDOM(λ) model for the fluvial-marine transition zone in the Laptev Sea The aCDOM(λ) characteristics revealed that the DOM in samples of this dataset are primarily of terrigenous origin. Observed changes in aCDOM and its spectral slopes indicate that DOM is modified by microbial- and photo-degradation. Ocean Color Remote Sensing (OCRS) provides the absorption coefficient of colored dissolved organic matter (aCDOM(λ)sat) at λ = 440 or 443 nm, which can be used to estimate DOC concentration at high temporal and spatial resolution over large regions. We tested the statistical performance of five OCRS algorithms and evaluated the plausibility of the spatial distribution of derived aCDOM(λ)sat. The ONNS algorithm showed the best performance compared to in situ aCDOM(440) (r2 = 0.72). Additionally, we found ONNS-derived aCDOM(440), in contrast to other algorithms, to be partly independent of sediment concentration, making ONNS the most suitable aCDOM(λ)sat algorithm for the Laptev Sea region. The DOC-aCDOM(λ) model was applied to ONNS-derived aCDOM(440) and retrieved DOC concentration maps showed moderate agreement to in situ data (r2 = 0.53). The in situ and satellite-retrieved data were offset by up to several days, which may partly explain the weak correlation for this dynamic region. Satellite-derived surface water DOC concentration maps from MERIS satellite data demonstrate rapid removal of DOC within short time periods in coastal waters of the Laptev Sea, which is likely caused by physical mixing and different types of degradation processes. Using samples from all occurring water types leads to a more robust DOC-aCDOM(λ) model for the retrievals of DOC in Arctic shelf and river waters. %0 journal article %@ 1812-0784 %A Callies, U., Carrasco, R., Floeter, J., Horstmann, J., Quante, M. %D 2019 %J Ocean Science %N 4 %P 865-889 %R doi:10.5194/os-15-865-2019 %T Submesoscale dispersion of surface drifters in a coastal sea near offshore wind farms %U https://doi.org/10.5194/os-15-865-2019 4 %X We analyse relative dispersion of surface drifters released as pairs (6 instances) or triplets (2 instances) during three field experiments in the German Bight in close proximity to wind farms. Drifter pairs can be classified in a remarkably clear way into those with spatial separation growing either exponentially or non-monotonously. There is some tentative evidence that exponential relative dispersion growth rates preferably occur for drifter pairs that are most exposed to the possible influence of a wind farm. Kinetic energy spectra and velocity structure functions suggest that turbulent energy could be injected by tides, possibly also via an interaction between tidal currents and wind turbine towers. Applicability of inertial range turbulence theory, however, can be doubted given distinct peaks of overtides observed in velocity power spectra. More comprehensive studies would be needed to better separate submesoscale effects of wind farms, tides and possibly baroclinic instabilities on observed drifter behaviour in a complex coastal environment. %0 journal article %@ 2072-4292 %A Ruddick, K.G., Voss, K., Boss, E., Castagna, A., Frouin, R., Gilerson, A., Hieronymi, M., Johnson, B.C., Kuusk, J., Lee, Z., Ondrusek, M., Vabson, V., Vendt, R. %D 2019 %J Remote Sensing %N 19 %P 2198 %R doi:10.3390/rs11192198 %T A Review of Protocols for Fiducial Reference Measurements of WaterLeaving Radiance for Validation of Satellite Remote-Sensing Data over Water %U https://doi.org/10.3390/rs11192198 19 %X This paper reviews the state of the art of protocols for measurement of waterleaving radiance in the context of fiducial reference measurements (FRM) of water reflectance for satellite validation. Measurement of water reflectance requires the measurement of waterleaving radiance and downwelling irradiance just above water. For the former there are four generic families of method, based on: 1) underwater radiometry at fixed depths; or 2) underwater radiometry with vertical profiling; or 3) abovewater radiometry with skyglint correction; or 4) onwater radiometry with skylight blocked. Each method is described generically in the FRM context with reference to the measurement equation, documented implementations and the intramethod diversity of deployment platform and practice. Ideal measurement conditions are stated, practical recommendations are provided on best practice and guidelines for estimating the measurement uncertainty are provided for each protocolrelated component of the measurement uncertainty budget. The state of the art for measurement of waterleaving radiance is summarized, future perspectives are outlined, and the question of which method is best adapted to various circumstances (water type, wavelength) is discussed. This review is based on practice and papers of the aquatic optics community for the validation of water reflectance estimated from satellite data but can be relevant also for other applications such as the development or validation of algorithms for remote-sensing estimation of water constituents including chlorophyll a concentration, inherent optical properties and related products. %0 journal article %@ 2169-9275 %A Shao, M., Ortiz-Suslow, D., Haus, B., Lund, B., Williams, N., Özgökmen, T., Laxague, N., Horstmann, J., Klymak, J. %D 2019 %J Journal of Geophysical Research : Oceans %N 11 %P 7756-7780 %R doi:10.1029/2019JC015236 %T The Variability of Winds and Fluxes Observed Near Submesoscale Fronts %U https://doi.org/10.1029/2019JC015236 11 %X Submesoscale oceanic fronts (SFs), which typically occur on a spatial scale of 0.1–10 km, may have a large influence on the atmospheric surface layer (ASL). However, due to their short temporal‐spatial scales, evaluating their direct impact on this layer remains challenging and characterizing the nature of SF‐ASL interaction has not been done in the field. To address this, a study of the air‐sea response to SFs was conducted using observations collected during the Lagrangian Submesoscale Experiment, which took place in the northern Gulf of Mexico. This manuscript focuses on the meteorological measurements made from a pair of masts installed on the bow of the R/V Walton Smith . This work represents one of the first observation‐based investigations into the potential influence that SFs have on the ASL. Contemporaneous measurements from an X‐band marine radar, moving vessel profiler, and Lagrangian drifters were also used to analyze the SF dynamics. Systematic surface wind velocity changes over several cross‐frontal transects were observed, a process previously associated with mesoscale fronts. A comparison between the eddy covariance and parameterized (COARE 3.5) air‐sea fluxes revealed that the directly observed heat flux was 1.5 times larger than the bulk value in the vicinity of the SFs. This suggests that the hydrodynamic processes near the front enhance the local exchange of sensible and latent heat. Given the prevalence of SF over the global upper ocean, these findings suggest that these features may have a widely distributed and cumulative impact on air‐sea interactions. %0 dataset %@ %A Cysewski, M., Streßer, M., Bödewadt, J., Perthun, P., Carrasco, R., Horstmann, J. %D 2019 %J Pangaea %R doi:10.1594/PANGAEA.898407 %T Single beam bathymetry transects at the West coast of Sylt from Sep 22-26 2016 %U https://doi.org/10.1594/PANGAEA.898407 %X The dataset contains quality checked, post processed echo soundings as point data (not gridded). It represents the coastal bathymetry in September 2016 in front of "Bunker Hill" at the southern West coast of the island Sylt, in the German Bight of the North Sea. The "WaveDiss" field experiment was conducted from September 21. to October 2., 2016 at the Island Sylt in the North Sea. The goal of the experiment is to provide ground truth data for validation and development of radar remote sensing methods to study nearshore hydro- and morphodynamics (Link: https://www.hzg.de/institutes_platforms/coastal_research/operational_systems/radar_hydrograph/projectsy/index.php.en#tab-25). %0 journal article %@ 0886-6236 %A Macovei, V.A., Torres-Valdes, S., Hartman, S., Schuster, U., Moore, C., Brown, P., Hydes, D., Sanders, R. %D 2019 %J Global Biogeochemical Cycles %N 12 %P 1674-1692 %R doi:10.1029/2018GB006132 %T Temporal Variability in the Nutrient Biogeochemistry of the Surface North Atlantic: 15 Years of Ship of Opportunity Data %U https://doi.org/10.1029/2018GB006132 12 %X Ocean biological processes play an important role in the global carbon cycle via the production of organic matter and its subsequent export. Often, this flux is assumed to be in steady state; however, it is dependent on nutrients introduced to surface waters via multiple mechanisms, some of which are likely to exhibit both intra-annual and interannual variability leading to comparable variability in ocean carbon uptake. Here we test this variability using surface (5 m) inorganic nutrient concentrations from voluntary observing ships and satellite-derived estimates of chlorophyll and net primary production. At lower latitudes, the seasonality is small, and the monthly averages of nitrate:phosphate are lower than the canonical 16:1 Redfield ratio, implying nitrogen limitation, a situation confirmed via a series of nutrient limitation experiments conducted between Bermuda and Puerto Rico. The nutrient seasonal cycle is more pronounced at higher latitudes, with clear interannual variability. Over a large area of the midlatitude North Atlantic, the winters of 2009/2010 and 2010/2011 had nitrate values more than 1μmol L−1 higher than the 2002–2017 average, suggesting that during this period, the system may have shifted to phosphorus limitation. This nitrate increase meant that, in the region between 31° and 39° N, new production calculated from nitrate uptake was 20.5g C m−2 in 2010, more than four times higher than the median value of the whole observing period. Overall, we suggest that substantial variability in nutrient concentrations and biological carbon uptake occurs in the North Atlantic with interannual variability apparent over a number of different time scales. %0 journal article %@ 0921-8971 %A Li, T., Podola, B., Schultze, L., Melkonian, M. %D 2019 %J Journal of Applied Phycology %P 1623-1636 %R doi:10.1007/s10811-018-1700-2 %T Design scenario analysis for porous substrate photobioreactor assemblies %U https://doi.org/10.1007/s10811-018-1700-2 %X For commercial-scale production of microalgae, in the recent years, biofilm bioreactors have been proven to solve some of major technical problems in this field. Among different approaches, porous substrate photobioreactor (PSBR) is one of the most promising bioreactor types. However, before the actual construction of such a system and application, various design parameters need to be determined. For this purpose, mathematical modeling is considered to be an efficient tool. In the present study, a model for estimating design parameters of PSBRs is proposed. The proposed model estimates the effects of different design parameters on the productivity of PSBR systems based on (1) global solar irradiance data, (2) geographical location of the simulated system, and (3) empirical functions describing the relationship between light intensity on the module surface and module productivity, derived from experimental data. In the present study, to demonstrate the capacity of the proposed model, production of Halochlorella rubescens using a PSBR (Twin-Layer technology) was modeled for various scenarios. Also, simulated production of astaxanthin using Haematococcus pluvialis was performed. The results demonstrated the ability of the proposed model to estimate various design parameters for PSBR systems under various conditions. Based on the prediction made by the proposed model, these parameters can be individually optimized for different geographical locations and/or applications. %0 journal article %@ 1539-3755 %A Heifetz, E., Guha, A. %D 2019 %J Physical Review E %N 4 %P 043105 %R doi:10.1103/PhysRevE.100.043105 %T Normal form of synchronization and resonance between vorticity waves in shear flow instability %U https://doi.org/10.1103/PhysRevE.100.043105 4 %X A minimal model of linearized two-dimensional shear instabilities can be formulated in terms of an action-at-a-distance, phase-locking resonance between two vorticity waves, which propagate counter to their local mean flow as well as counter to each other. Here we analyze the prototype of this interaction as an autonomous, nonlinear dynamical system. The wave interaction equations can be written in a generalized Hamiltonian action-angle form. The pseudoenergy serves as the Hamiltonian of the system, the action coordinates are the contribution of the vorticity waves to the wave action, and the angles are the phases of the vorticity waves. The term “generalized action angle” emphasizes that the action of each wave is generally time dependent, which allows instability. The synchronization mechanism between the wave phases depends on the cosine of their relative phase, rather than the sine as in the Kuramoto model. The unstable normal modes of the linearized dynamics correspond to the stable fixed points of the dynamical system and vice versa. Furthermore, the normal form of the wave interaction dynamics reveals a new type of inhomogeneous bifurcation: annihilation of a stable and an unstable star node yields the emergence of two neutral center fixed points of opposite circulation. %0 journal article %@ 0022-1120 %A Alam, S., Guha, A., Verma, M. %D 2019 %J Journal of Fluid Mechanics %P 961-973 %R doi:10.1017/jfm.2019.529 %T Revisiting Bolgiano–Obukhov scaling for moderately stably stratified turbulence %U https://doi.org/10.1017/jfm.2019.529 %X According to the celebrated Bolgiano–Obukhov (Bolgiano, J. Geophys. Res., vol. 64 (12), 1959, pp. 2226–2229; Obukhov, Dokl. Akad. Nauk SSSR, vol. 125, 1959, p. 1246) phenomenology for moderately stably stratified turbulence, the energy spectrum in the inertial range shows a dual scaling: the kinetic energy follows (i) ∼k−11/5 for kkB , where kB is the Bolgiano wavenumber. The k−5/3 scaling, akin to passive scalar turbulence, is a direct consequence of the assumption that buoyancy is insignificant for k>kB . We revisit this assumption, and using the constancy of kinetic and potential energy fluxes and simple theoretical analysis, we find that the k−5/3 spectrum is absent. This is because the velocity field at small scales is too weak to establish a constant kinetic energy flux as in passive scalar turbulence. A quantitative condition for the existence of the second regime is also derived in the paper. %0 journal article %@ 2073-4433 %A Sattler, T., Sörgel, M., Wittmer, J., Bourtsoukidis, E., Krause, T., Atlas, E., Benk, S., Bleicher, S., Kamilli, K., Ofner, J., Kopetzky, R., Held, A., Palm, W.-U., Williams, J., Zetzsch, C., Schöler, H.-F. %D 2019 %J Atmosphere %N 11 %P 663 %R doi:10.3390/atmos10110663 %T Natural Formation of Chloro- and Bromoacetone in Salt Lakes of Western Australia %U https://doi.org/10.3390/atmos10110663 11 %X Western Australia is a semi-/arid region known for saline lakes with a wide range of geochemical parameters (pH 2.5–7.1, Cl− 10–200 g L−1). This study reports on the haloacetones chloro- and bromoacetone in air over 6 salt lake shorelines. Significant emissions of chloroacetone (up to 0.2 µmol m−2 h−1) and bromoacetone (up to 1. 5 µmol m−2 h−1) were detected, and a photochemical box model was employed to evaluate the contribution of their atmospheric formation from the olefinic hydrocarbons propene and methacrolein in the gas phase. The measured concentrations could not explain the photochemical halogenation reaction, indicating a strong hitherto unknown source of haloacetones. Aqueous-phase reactions of haloacetones, investigated in the laboratory using humic acid in concentrated salt solutions, were identified as alternative formation pathway by liquid-phase reactions, acid catalyzed enolization of ketones, and subsequent halogenation. In order to verify this mechanism, we made measurements of the Henry’s law constants, rate constants for hydrolysis and nucleophilic exchange with chloride, UV-spectra and quantum yields for the photolysis of bromoacetone and 1,1-dibromoacetone in the aqueous phase. We suggest that heterogeneous processes induced by humic substances in the quasi-liquid layer of the salt crust, particle surfaces and the lake water are the predominating pathways for the formation of the observed haloacetones. %0 journal article %@ 2296-7745 %A Lombard, F., Boss, E., Waite, A.M., Uitz, J., Stemmann, L., Sosik, H.M., Schulz, J., Romagnan, J.-B., Picheral, M., Pearlman, J., Ohman, M.D., Niehoff, B., Möller, K.O., Miloslavich, P., Lara-Lopez, A., Kudela, R.M., Lopes, R.M., Karp-Boss, L., Kiko, R., Jaffe, J.S., Iversen, M.H., Irisson, J.-O., Hauss, H., Guidi, L., Gorsky, G., Giering, S.L.C., Gaube, P., Gallager, S., Dubelaar, G., Cowen, R.K., Carlotti, F., Briseño-Avena, C., Berline, L., Benoit-Bird, K.J., Bax, N.J., Batten, S.D., Ayata, S.-D., Appeltans, W. %D 2019 %J Frontiers in Marine Science %P 196 %R doi:10.3389/fmars.2019.00196 %T Globally Consistent Quantitative Observations of Planktonic Ecosystems %U https://doi.org/10.3389/fmars.2019.00196 %X In this paper we review the technologies available to make globally quantitative observations of particles in general—and plankton in particular—in the world oceans, and for sizes varying from sub-microns to centimeters. Some of these technologies have been available for years while others have only recently emerged. Use of these technologies is critical to improve understanding of the processes that control abundances, distributions and composition of plankton, provide data necessary to constrain and improve ecosystem and biogeochemical models, and forecast changes in marine ecosystems in light of climate change. In this paper we begin by providing the motivation for plankton observations, quantification and diversity qualification on a global scale. We then expand on the state-of-the-art, detailing a variety of relevant and (mostly) mature technologies and measurements, including bulk measurements of plankton, pigment composition, uses of genomic, optical and acoustical methods as well as analysis using particle counters, flow cytometers and quantitative imaging devices. We follow by highlighting the requirements necessary for a plankton observing system, the approach to achieve it and associated challenges. We conclude with ranked action-item recommendations for the next 10 years to move toward our vision of a holistic ocean-wide plankton observing system. Particularly, we suggest to begin with a demonstration project on a GO-SHIP line and/or a long-term observation site and expand from there, ensuring that issues associated with methods, observation tools, data analysis, quality assessment and curation are addressed early in the implementation. Global coordination is key for the success of this vision and will bring new insights on processes associated with nutrient regeneration, ocean production, fisheries and carbon sequestration. %0 journal article %@ 0022-1120 %A Suzuki, N. %D 2019 %J Journal of Fluid Mechanics %P 906-950 %R doi:10.1017/jfm.2019.752 %T On the physical mechanisms of the two-way coupling between a surface wave field and a circulation consisting of a roll and streak %U https://doi.org/10.1017/jfm.2019.752 %X The governing equations of a surface wave field and a coexisting roll–streak circulation typical of Langmuir circulations or submesoscale frontal circulations are derived to better describe their two-way interactions. The gradients and vertical velocities of the roll–streak circulation induce wave refraction, amplitude modulation and higher-order waves. These changes then produce wave–wave nonlinear forces and divergence of the wave-induced mass transport, both of which in turn affect the circulation. To accurately represent these processes, both a wave theory and a wave-averaged theory are developed without relying on any extrapolation, any spatiotemporal mapping or an approximation that treats the wave-induced mass divergence as being concentrated at the surface. This wave theory finds seven types of current-induced higher-order wave motions. It also determines the wave dynamics such as the governing equation of the wave action density valid in the presence of the complex circulation. The evolution of the wave action density is clearly affected by the upwelling or downwelling. The new wave-averaged theory presents the governing equations of the wave-averaged circulation which satisfies the wave-averaged mass conservation. This circulation is different from the circulation considered to satisfy the mass conservation in the Craik–Leibovich theory, and the difference becomes critical when the wave field evolves due to refraction. In this case, compared to the Craik–Leibovich theory, long waves are more important and also the rolls are more weakly forced. %0 journal article %@ 1424-8220 %A Nehir, M., Frank, C., Aßmann, S., Achterberg, E. %D 2019 %J Sensors %N 12 %P 2833 %R doi:10.3390/s19122833 %T Improving Optical Measurements: Non-Linearity Compensation of Compact Charge-Coupled Device (CCD) Spectrometers %U https://doi.org/10.3390/s19122833 12 %X Charge-coupled device (CCD) spectrometers are widely used as detectors in analytical laboratory instruments and as sensors for in situ optical measurements. However, as the applications become more complex, the physical and electronic limits of the CCD spectrometers may restrict their applicability. The errors due to dark currents, temperature variations, and blooming can be readily corrected. However, a correction for uncertainty of integration time and wavelength calibration is typically lacking in most devices, and detector non-linearity may distort the signal by up to 5% for some measurements. Here, we propose a simple correction method to compensate for non-linearity errors in optical measurements where compact CCD spectrometers are used. The results indicate that the error due to the non-linearity of a spectrometer can be reduced from several hundred counts to about 40 counts if the proposed correction function is applied. %0 journal article %@ 1942-2466 %A Schubert, R., Schwarzkopf, F., Baschek, B., Biastoch, A. %D 2019 %J Journal of Advances in Modeling Earth Systems : JAMES %N 8 %P 2745-2767 %R doi:10.1029/2019MS001724 %T Submesoscale Impacts on Mesoscale Agulhas Dynamics %U https://doi.org/10.1029/2019MS001724 8 %X Mesoscale dynamics of the Agulhas Current system determine the exchange between the Indian and Atlantic oceans, thereby influencing the global overturning circulation. Using a series of ocean model experiments compared to observations, we show that the representation of mesoscale eddies in the Agulhas ring path improves with increasing resolution of submesoscale flows. Simulated submesoscale dynamics are validated with time-mean horizontal-wavenumber spectra from satellite sea surface temperature measurements and mesoscale dynamics with spectra from sea surface height. While the Agulhas ring path in a nonsubmesoscale-resolving (1/20)° configuration is associated with too less power spectral densities on all scales and too steep spectral slopes, the representation of the mesoscale dynamics improves when the diffusion and the dissipation of the model are reduced and some small-scale features are resolved. Realistic power spectral densities over all scales are achieved when additionally the horizontal resolution is increased to (1/60)° and a larger portion of the submesoscale spectrum is resolved. Results of an eddy detection algorithm applied to the model outputs as well as to a gridded sea surface height satellite product show that in particular strong cyclones are much better represented when submesoscale flows are resolved by the model. The validation of the submesoscale dynamics with sea surface temperature spectra provides guidance for the choice of advection schemes and explicit diffusion and dissipation as well as for further subgrid-scale parameterizations. For the Agulhas ring path, the use of upstream biased advection schemes without explicit diffusion and dissipation is found to be associated with realistically simulated submesoscales. %0 editorial %@ 2169-3536 %A Huang, W., Lund, B., Horstmann, J. %D 2019 %J IEEE Access %P 18899-18901 %R doi:10.1109/ACCESS.2019.2895442 %T IEEE Access Special Section Editorial: Microwave (X- and S-Band) Marine Radars for Ocean Sensing %U https://doi.org/10.1109/ACCESS.2019.2895442 %X Non-coherent X-band (8–12 GHz) and S-band (2–4 GHz) marine radars have been used to aid the navigation of ships and monitor the traffic in coastal areas for decades. These traditional marine radar (MR) applications treat the radar return from the sea surface, or sea clutter, as a noise that must be suppressed. In recent years, there has been a growing interest in X- and S-band MR ocean sensing. Non-coherent MRs have shown to yield accurate surface wave frequency-direction spectra, maps of the sea surface elevation, the near-surface current, and the bathymetry, as well as surface wind information, among other parameters, under a broad range of environmental conditions. Meanwhile, MR technology is undergoing a transition towards a fully coherent and solid state architecture. In MR ocean sensing, coherent on-receive magnetron-based systems are finding broader use. It has been shown to yield accurate significant wave heights and is being used to improve our understanding of grazing incidence radar scattering mechanisms. Lately, digital signal processing is becoming more commonplace in off-the-shelf commercial MRs and significantly broaden the scope and potential of oceanographic applications. %0 book part %@ %A Heim, B., Juhls, B., Abramova, E., Bracher, A., Doerffer, R., Gonçalves-Araujo, R., Hellman, S., Kraberg, A., Martynov, F., Overduin, P. %D 2019 %J Remote Sensing of the Asian Seas %P 123-138 %R doi:10.1007/978-3-319-94067-0_6 %T Ocean Colour Remote Sensing in the Laptev Sea %U https://doi.org/10.1007/978-3-319-94067-0_6 %X The Laptev and Eastern Siberian shelves are the world’s broadest shallow shelf systems. Large Siberian rivers and coastal erosion of up to meters per summer deliver large volumes of terrestrial matter into the Arctic shelf seas. In this chapter we investigate the applicability of Ocean Colour Remote Sensing during the ice-free summer season in the Siberian Laptev Sea region. We show that the early summer river peak discharge may be traced using remote sensing in years characterized by early sea-ice retreat. In the summer time after the peak discharge, the spreading of the main Lena River plume east and north-east of the Lena River Delta into the shelf system becomes hardly traceable using optical remote sensing methods. Measurements of suspended particulate matter (SPM) and coloured dissolved organic matter (cDOM) are of the same magnitude in the coastal waters of Buor Khaya Bay as in the Lena River. Match-up analyses of in situ chlorophyll-a (Chl-a) show that standard Medium Resolution Imaging Spectrometer (MERIS) and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite-derived Chl-a is not a valid remote sensing product for the coastal waters and the inner shelf region of the Laptev Sea. All MERIS and MODIS-derived Chl-a products are overestimated by at least a factor of ten, probably due to absorption by the extraordinarily high amount of non-algal particles and cDOM in these coastal and inner-shelf waters. Instead, Ocean Colour remote sensing provides information on wide-spread resuspension over shallows and lateral advection visible in satellite-derived turbidity. Satellite Sea Surface Temperature (SST) data clearly show hydrodynamics and delineate the outflow of the Lena River for hundreds of kilometres out into the shelf seas. %0 doctoral thesis %@ %A Schultze, L.K.P. %D 2018 %J %T Natural variability of turbulence and stratification in a tidal shelf sea and the possible impact of offshore wind farms (Dissertation) %U %X %0 journal article %@ 2072-4292 %A Ruescas, A.B., Hieronymi, M., Mateo-Garcia, G., Koponen, S., Kallio, K., Camps-Valls, G. %D 2018 %J Remote Sensing %N 5 %P 786 %R doi:10.3390/rs10050786 %T Machine Learning Regression Approaches for Colored Dissolved Organic Matter (CDOM) Retrieval with S2-MSI and S3-OLCI Simulated Data %U https://doi.org/10.3390/rs10050786 5 %X The colored dissolved organic matter (CDOM) variable is the standard measure of humic substance in waters optics. CDOM is optically characterized by its spectral absorption coefficient, a CDOM aCDOM at at reference wavelength (e.g., ≈ 440 nm). Retrieval of CDOM is traditionally done using bio-optical models. As an alternative, this paper presents a comparison of five machine learning methods applied to Sentinel-2 and Sentinel-3 simulated reflectance ( R rs Rrs ) data for the retrieval of CDOM: regularized linear regression (RLR), random forest regression (RFR), kernel ridge regression (KRR), Gaussian process regression (GPR) and support vector machines (SVR). Two different datasets of radiative transfer simulations are used for the development and training of the machine learning regression approaches. Statistics comparison with well-established polynomial regression algorithms shows optimistic results for all models and band combinations, highlighting the good performance of the methods, especially the GPR approach, when all bands are used as input. Application to an atmospheric corrected OLCI image using the reflectance derived form the alternative neural network (Case 2 Regional) is also shown. Python scripts and notebooks are provided to interested users. %0 journal article %@ 2072-4292 %A Goeritz, A., Berger, S.A., Gege, P., Grossart, H.-P., Nejsrgaard, J.C., Riedel, S., Roettgers, R., Utschig, C. %D 2018 %J Remote Sensing %N 2 %P 181 %R doi:10.3390/rs10020181 %T Retrieval of Water Constituents from Hyperspectral In-Situ Measurements under Variable Cloud Cover—A Case Study at Lake Stechlin (Germany) %U https://doi.org/10.3390/rs10020181 2 %X Remote sensing and field spectroscopy of natural waters is typically performed under clear skies, low wind speeds and low solar zenith angles. Such measurements can also be made, in principle, under clouds and mixed skies using airborne or in-situ measurements; however, variable illumination conditions pose a challenge to data analysis. In the present case study, we evaluated the inversion of hyperspectral in-situ measurements for water constituent retrieval acquired under variable cloud cover. First, we studied the retrieval of Chlorophyll-a (Chl-a) concentration and colored dissolved organic matter (CDOM) absorption from in-water irradiance measurements. Then, we evaluated the errors in the retrievals of the concentration of total suspended matter (TSM), Chl-a and the absorption coefficient of CDOM from above-water reflectance measurements due to highly variable reflections at the water surface. In order to approximate cloud reflections, we extended a recent three-component surface reflectance model for cloudless atmospheres by a constant offset and compared different surface reflectance correction procedures. Our findings suggest that in-water irradiance measurements may be used for the analysis of absorbing compounds even under highly variable weather conditions. The extended surface reflectance model proved to contribute to the analysis of above-water reflectance measurements with respect to Chl-a and TSM. Results indicate the potential of this approach for all-weather monitoring. %0 journal article %@ 2169-9275 %A Fransner, F., Gustafsson, E., Tedesco, L., Vichi, M., Hordoir, R., Roquet, F., Spilling, K., Kuznetsov, I., Eilola, K., Moerth, C.-M., Humborg, C., Nycander, J. %D 2018 %J Journal of Geophysical Research : Oceans %N 1 %P 166-188 %R doi:10.1002/2017JC013019 %T Non-Redfieldian Dynamics Explain Seasonal pCO2 Drawdown in the Gulf of Bothnia %U https://doi.org/10.1002/2017JC013019 1 %X High inputs of nutrients and organic matter make coastal seas places of intense air-sea CO2 exchange. Due to their complexity, the role of coastal seas in the global air-sea CO2 exchange is, however, still uncertain. Here, we investigate the role of phytoplankton stoichiometric flexibility and extracellular DOC production for the seasonal nutrient and CO2 partial pressure (pCO2) dynamics in the Gulf of Bothnia, Northern Baltic Sea. A 3-D ocean biogeochemical-physical model with variable phytoplankton stoichiometry is for the first time implemented in the area and validated against observations. By simulating non-Redfieldian internal phytoplankton stoichiometry, and a relatively large production of extracellular dissolved organic carbon (DOC), the model adequately reproduces observed seasonal cycles in macronutrients and pCO2. The uptake of atmospheric CO2 is underestimated by 50% if instead using the Redfield ratio to determine the carbon assimilation, as in other Baltic Sea models currently in use. The model further suggests, based on the observed drawdown of pCO2, that observational estimates of organic carbon production in the Gulf of Bothnia, derived with the math formula method, may be heavily underestimated. We conclude that stoichiometric variability and uncoupling of carbon and nutrient assimilation have to be considered in order to better understand the carbon cycle in coastal seas. %0 journal article %@ 0003-6935 %A Agagliate, J., Roettgers, R., Twardowski, M.S., McKee, D. %D 2018 %J Applied Optics %N 7 %P 1705-1716 %R doi:10.1364/AO.57.001705 %T Evaluation of a flow cytometry method to determine size and real refractive index distributions in natural marine particle populations %U https://doi.org/10.1364/AO.57.001705 7 %X A flow cytometric (FC) method was developed to retrieve particle size distributions (PSDs) and real refractive index (𝑛 𝑟 nr) information in natural waters. Geometry and signal response of the sensors within the flow cytometer (CytoSense, CytoBuoy b.v., Netherlands) were characterized to form a scattering inversion model based on Mie theory. The procedure produced a mesh of diameter and 𝑛 𝑟 nr isolines where each particle is assigned the diameter and 𝑛 𝑟 nr values of the closest node, producing PSDs and particle real refractive index distributions. The method was validated using polystyrene bead standards of known diameter and polydisperse suspensions of oil with known 𝑛 𝑟 nr, and subsequently applied to natural samples collected across a broad range of UK shelf seas. FC PSDs were compared with independent PSDs produced from data of two LISST-100X instruments (type B and type C). PSD slopes and features were found to be consistent between the FC and the two LISST-100X instruments, but LISST concentrations were found in disagreement with FC concentrations and with each other. FC 𝑛 𝑟 nr values were found to agree with expected refractive index values of typical marine particle components across all samples considered. The determination of particle size and refractive index distributions enabled by the FC method has potential to facilitate identification of the contribution of individual subpopulations to the bulk inherent optical properties and biogeochemical properties of the particle population. %0 journal article %@ 2169-9275 %A Testor, P., Bosse, A., Houpert, L., Margirier, F., Mortier, L., Legoff, H., Dausse, D., Labaste, M., Karstensen, J., Hayes, D., Olita, A., Ribotti, A., Schroeder, K., Chiggiato,, J., Onken, R., Heslop, E., Mourre, B., D'Ortenzio, F., Mayot, N., Lavigne, H., de Fommervault, O., Coppola, L., Prieur, L., Taillandier, V., Durrieu de Madron, X., Bourrin, F., Many, G., Damien, P., Estournel, C., Marsaleix, P., Taupier-Letage, I., Raimbault, P., Waldman, R., Bouin, M.-N., Giordani, H., Caniaux, G., Somot, S., Ducrocq, V., Conan, P. %D 2018 %J Journal of Geophysical Research : Oceans %N 3 %P 1745-1776 %R doi:10.1002/2016JC012671 %T Multiscale Observations of Deep Convection in the Northwestern Mediterranean Sea During Winter 2012-2013 Using Multiple Platforms %U https://doi.org/10.1002/2016JC012671 3 %X During winter 2012-2013, open-ocean deep convection which is a major driver for the thermohaline circulation and ventilation of the ocean, occurred in the Gulf of Lions (Northwestern Mediterranean Sea) and has been thoroughly documented thanks in particular to the deployment of several gliders, Argo profiling floats, several dedicated ship cruises, and a mooring array during a period of about a year. Thanks to these intense observational efforts, we show that deep convection reached the bottom in winter early in February 2013 in a area of maximum 28±3 109m9. We present new quantitative results with estimates of heat and salt content at the sub-basin scale at different time scales (on the seasonal scale to a ten days basis) through optimal interpolation techniques, and robust estimates of the deep water formation rate of 2.0 ± 0.2Sν. We provide an overview of the spatio-temporal coverage that has been reached throughout the seasons this year and we highlight some results based on data analysis and numerical modeling that are presented in this special issue. They concern key circulation features for the deep convection and the subsequent bloom such as Submesoscale Coherent Vortices (SCVs), the plumes and symmetric instability at the edge of the deep convection area. %0 journal article %@ 1812-0784 %A Onken, R., Fiekas, H.-V., Beguery, L., Borrione, I., Funk, A., Hemming, M., Heywood, K.J., Kaiser, J., Knoll, M., Poulain, P.-M., Queste, B., Russo, A., Shitashima, K., Siderius, M., Thorp Kuesel, E. %D 2018 %J Ocean Science %N 2 %P 321-335 %R doi:10.5194/os-14-321-2018 %T High-Resolution Observations in the Western Mediterranean Sea: The REP14-MED Experiment %U https://doi.org/10.5194/os-14-321-2018 2 %X The observational part of the REP14-MED experiment was conducted in June 2014 in the Sardo-Balearic Basin west of Sardinia (western Mediterranean Sea). Two research vessels collected high-resolution oceanographic data by means of hydrographic casts, towed systems, and underway measurements. In addition, a vast amount of data was provided by a fleet of 11 ocean gliders, time series were available from moored instruments, and information on Lagrangian flow patterns was obtained from surface drifters and one profiling float. The spatial resolution of the observations encompasses a spectrum over 4 orders of magnitude from 𝒪(101 m) to 𝒪(105 m), and the time series from the moored instruments cover a spectral range of 5 orders from 𝒪(101 s) to 𝒪(106 s). The objective of this article is to provide an overview of the huge data set which has been utilised by various studies, focusing on (i) water masses and circulation, (ii) operational forecasting, (iii) data assimilation, (iv) variability of the ocean, and (v) new payloads for gliders. %0 journal article %@ 0739-0572 %A Lund, B., Haus, B.K., Horstmann, J., Graber, H.C., Carrasco, R., Laxague, N.J.M., Novelli, G., Guigand, C.M., Oezgoekmen, T.M. %D 2018 %J Journal of Atmospheric and Oceanic Technology %N 5 %P 1077-1090 %R doi:10.1175/JTECH-D-17-0154.1 %T Near-Surface Current Mapping by Shipboard Marine X-Band Radar: A Validation %U https://doi.org/10.1175/JTECH-D-17-0154.1 5 %X The Lagrangian Submesoscale Experiment (LASER) involved the deployment of ~1000 biodegradable GPS-tracked Consortium for Advanced Research on Transport of Hydrocarbon in the Environment (CARTHE) drifters to measure submesoscale upper-ocean currents and their potential impact on oil spills. The experiment was conducted from January to February 2016 in the Gulf of Mexico (GoM) near the mouth of the Mississippi River, an area characterized by strong submesoscale currents. A Helmholtz-Zentrum Geesthacht (HZG) marine X-band radar (MR) on board the R/V F. G. Walton Smith was used to locate fronts and eddies by their sea surface roughness signatures. The MR data were further processed to yield near-surface current maps at ~500-m resolution up to a maximum range of ~3 km. This study employs the drifter measurements to perform the first comprehensive validation of MR near-surface current maps. For a total of 4130 MR–drifter pairs, the root-mean-square error for the current speed is 4 cm and that for the current direction is 12°. The MR samples currents at a greater effective depth than the CARTHE drifters (1–5 m vs ~0.4 m). The mean MR–drifter differences are consistent with a wave- and wind-driven vertical current profile that weakens with increasing depth and rotates clockwise from the wind direction (by 0.7% of the wind speed and 15°). The technique presented here has great potential in observational oceanography, as it allows research vessels to map the horizontal flow structure, complementing the vertical profiles measured by ADCP. %0 journal article %@ 2169-9275 %A Androulidakis, Y., Kourafalou, V., Oezgoekmen, T., Garcia-Pineda, O., Lund, B., Le Henaff, M., Hu, C., Haus, B.K., Novelli, G., Guigand, C., Kang, H., Hole, L., Horstmann, J. %D 2018 %J Journal of Geophysical Research : Oceans %N 5 %P 3259-3285 %R doi:10.1029/2017JC013514 %T Influence of River-Induced Fronts on Hydrocarbon Transport: A Multiplatform Observational Study %U https://doi.org/10.1029/2017JC013514 5 %X The Taylor Energy Site is located in the vicinity of the Mississippi Delta region over the Northern Gulf of Mexico (NGoM). Surface oil patches have been persistently observed within this site since 2004, when an oil rig was destroyed by Hurricane Ivan. A multiplatform observational experiment was conducted in April 2017 to investigate, for the first time, the main hydrocarbon pathways from the Taylor Energy Site toward the NGoM continental shelves, and the Gulf interior, under the influence of local and regional physical processes. Results indicate that the Mississippi River (MR)‐induced fronts over the Taylor Energy Site, in combination with local circulation, prevailing winds and broader regional dynamics determine the hydrocarbon transport. The drifters deployed during the field experiment, in tandem with satellite data, drone imagery, wind measurements, and radar‐derived data, efficiently described three major hydrocarbon pathways, associated with MR plume dynamics (downstream/upstream coastal currents) and basin‐wide circulation (offshore pathway). Two different types of drifters, drogued and undrogued, showed clearly different pathways, which suggest potential differences in the expected advection of oil, depending on whether it forms a surface slick or whether it is partially mixed below the surface. The existence of multiple river fronts influenced the fate of oiled waters, preventing the hydrocarbons from reaching the Delta, like a natural boom barrier, trapping and directing the oil either westward or eastward. Thermohaline measurements showed that the MR plume near Taylor was 5–10 m deep, while the clearer ocean was characterized by a 40 m upper ocean homogenous layer. %0 journal article %@ 1175-5326 %A Borges, L.M.S., Merckelbach, L. %D 2018 %J Zootaxa %N 3 %P 441-457 %R doi:10.11646/zootaxa.4442.3.6 %T Lyrodus mersinensis sp. nov. (Bivalvia: Teredinidae) another cryptic species in the Lyrodus pedicellatus (Quatrefages, 1849) complex %U https://doi.org/10.11646/zootaxa.4442.3.6 3 %X New data from barcode index numbers (BINs) and 28S rRNA gene sequences confirm a cryptic species pair in Lyrodus pedicellatus from the eastern Mediterranean and European Atlantic coasts. Therefore, it is paramount to associate the new species to a scientific name for a reliable reference system of biological information. To this end, we describe Lyrodus mersinensis sp. nov., another cryptic species in the L. pedicellatus complex, and redescribe the `true´ L. pedicellatus. Both the description and redescription are based on molecular diagnostic characters obtained from sequences of the mitochondrial cytochrome c oxidase subunit I (COI) and nuclear 28S rRNA genes. The 18S rRNA gene sequences did not yield diagnostic characters to distinguish these species. A morphological diagnosis of pedicellatus-like Lyrodus species is also provided. %0 book part %@ %A Beusekom, J.E.E.van, Thiel, R., Bobsien, I., Boersma, M., Buschbaum, C., Daenhardt, A., Darr, A., Friedland, R., Kloppmann, M., Kroencke, I., Rick, J., Wetzel, M. %D 2018 %J Hamburger Klimabericht – Wissen ueber Klima, Klimawandel und Auswirkungen in Hamburg und Norddeutschland %P 89-107 %R doi:10.1007/978-3-662-55379-4_5 %T Aquatische Oekosysteme: Nordsee, Wattenmeer, Elbeaestuar und Ostsee %U https://doi.org/10.1007/978-3-662-55379-4_5 %X Im 1. Klimabericht für die Metropolregion Hamburg (1. HKB; Colijn und Fanger 2011) wurde die Klimaauswirkung auf das Phyto- und Zooplankton, das Makrozoobenthos und die Fische in Nordsee, Wattenmeer und Elbeästuar dargelegt. Die Autoren zeigten, dass insbesondere die Wassertemperatur und Hydrodynamik die Variabilität der Ökosysteme prägten, während hin zum Wattenmeer und Elbeästuar die Interaktion mit anthropogenen Faktoren zunahm und vermutlich die zukünftige ökologische Entwicklung prägen wird. %0 journal article %@ 1094-4087 %A Lefering, I., Roettgers, R., Utschig, C., Twardowsky, M.S., McKee, D. %D 2018 %J Optics express %N 19 %P 24384-24402 %R doi:10.1364/OE.26.024384 %T Measurement uncertainties in PSICAM and reflective tube absorption meters %U https://doi.org/10.1364/OE.26.024384 19 %X The nature and magnitude of measurement uncertainties (precision and accuracy) associated with two approaches for measuring absorption by turbid waters (b(532 nm) ranging from 0.20 m−1 to 22.89 m−1) are investigated here: (a) point source integrating cavity absorption meters (PSICAM), and (b) reflective tube absorption meters (AC-9 and AC-s – both WET Labs Inc., USA). Absolute measurement precision at 440 nm was quantified using standard deviations of triplicate measurements for the PSICAM and de-trended, bin averaged time series for the AC-9/s, giving comparable levels (< 0.006 m−1) for both instruments. Using data collected from a wide range of UK coastal waters, PSICAM accuracy was assessed by comparing both total non-water absorption and absorption by coloured dissolved organic material (CDOM) measured on discrete samples by two independent PSICAMs. AC-9/s performance was tested by comparing total non-water absorption measured in situ by an AC-9 and an AC-s mounted on the same frame. Results showed that the PSICAM outperforms AC-9/s instruments with regards to accuracy, with average spread in the PSICAM total absorption data of 0.006 m−1 (RMSE) compared to 0.028 m−1 for the AC-9/s devices. Despite application of a state of the art scattering correction method, the AC-9/s instruments still tend to overestimate absorption compared to PSICAM data by on average 0.014 m−1 RMSE (AC-s) and 0.043 m−1 RMSE (AC-9). This remaining discrepancy can be largely attributed to residual limitations in the correction of AC-9/s data for scattering effects and limitations in the quality of AC-9/s calibration measurements. %0 journal article %@ 2076-3417 %A Agagliate, J., Roettgers, R., Heymann, K., Connor, D., McKee, D. %D 2018 %J Applied Sciences %N 12 %P 2676 %R doi:10.3390/app8122676 %T Estimation of Suspended Matter, Organic Carbon, and Chlorophyll-a Concentrations from Particle Size and Refractive Index Distributions %U https://doi.org/10.3390/app8122676 12 %X Models of particle density and of organic carbon and chlorophyll-a intraparticle concentration were applied to particle size distributions and particle real refractive index distributions determined from flow cytometry measurements of natural seawater samples from a range of UK coastal waters. The models allowed for the estimation of suspended particulate matter, organic suspended matter, inorganic suspended matter, particulate organic carbon, and chlorophyll-a concentrations. These were then compared with independent measurements of each of these parameters. Particle density models were initially applied to a simple spherical model of particle volume, but generally overestimated independently measured values, sometimes by over two orders of magnitude. However, when the same density models were applied to a fractal model of particle volume, successful agreement was reached for suspended particulate matter and both inorganic and organic suspended matter values (RMS%E: 57.4%, 148.5%, and 83.1% respectively). Non-linear organic carbon and chlorophyll-a volume scaling models were also applied to a spherical model of particle volume, and after an optimization procedure achieved successful agreement with independent measurements of particulate organic carbon and chlorophyll-a concentrations (RMS%E: 45.6% and 51.8% respectively). Refractive index-based models of carbon and chlorophyll-a intraparticle concentration were similarly tested, and were also found to require a fractal model of particle volume to achieve successful agreement with independent measurements, producing RMS%E values of 50.2% and 45.2% respectively after an optimization procedure. It is further shown that the non-linear exponents of the volume scaling models are mathematically equivalent to the fractal dimensionality coefficients that link cell volume to mass concentration, reflecting the impact of non-uniform distribution of intracellular carbon within cells. Fractal models of particle volume are thus found to be essential to successful closure between results provided by models of particle mass, intraparticle carbon and chlorophyll content, and bulk measurements of suspended mass and total particulate carbon and chlorophyll when natural mixed particle populations are concerned. The results also further confirm the value of determining both size and refractive index distributions of natural particle populations using flow cytometry. %0 journal article %@ 2169-9275 %A Scheifele, B., Waterman, S., Merckelbach, L., Carpenter, J.R. %D 2018 %J Journal of Geophysical Research : Oceans %N 8 %P 5459-5480 %R doi:10.1029/2017JC013731 %T Measuring the Dissipation Rate of Turbulent Kinetic Energy in Strongly Stratified, Low‐Energy Environments: A Case Study From the Arctic Ocean %U https://doi.org/10.1029/2017JC013731 8 %X We compare estimates of the turbulent dissipation rate, ε, obtained independently from coincident measurements of shear and temperature microstructure in the southeastern Beaufort Sea, a strongly stratified, low‐energy environment. The measurements were collected over 10 days in 2015 by an ocean glider equipped with microstructure instrumentation; they yield 28,575 shear‐derived and 21,577 temperature‐derived ε estimates. We find agreement within a factor of 2 from the two types of estimates when ε exceeds 3 × 10−11 W/kg, a threshold we identify as the noise floor of the shear‐derived estimates. However, the temperature‐derived estimates suggest that the dissipation rate is lower than this threshold in 58% of our observations. Further, the noise floor of the shear measurements artificially skews the statistical distribution of ε below 10−10 W/kg, that is, in 70% of our observations. The shear measurements overestimate portions of the geometric mean vertical profile of ε by more than an order of magnitude and underestimate the overall variability of ε by at least 2 orders of magnitude. We further discuss uncertainties that arise in both temperature‐ and shear‐derived ε estimates in strongly stratified, weakly turbulent conditions, and we demonstrate how turbulence spectra are systematically modified by stratification under these conditions. Using evidence from the temperature‐gradient spectral shapes and from the observed ε distributions, we suggest that the temperature‐derived dissipation rates are reliable to values as small as 2 × 10−12 W/kg, making them preferable for characterizing the turbulent dissipation rates in the weakly turbulent environment of this study. %0 journal article %@ 1866-3508 %A Petersen, W., Reinke, S., Breitbach, G., Petschatnikov, M., Wehde, H., Thomas, H. %D 2018 %J Earth System Science Data %N 3 %P 1729-1734 %R doi:10.5194/essd-10-1729-2018 %T FerryBox Data in the North Sea from 2002 to 2005 %U https://doi.org/10.5194/essd-10-1729-2018 3 %X From 2002 to 2005 a FerryBox system was installed aboard two different ferries travelling between Cuxhaven (GE) and Harwich (UK) on a daily basis. The FerryBox system is an automated flow-through monitoring system for measuring oceanographic and biogeochemical parameters installed on ships of opportunity. The variables were recorded in a time interval of 10–20 seconds corresponding to a spatial resolution of about 100 m. The dataset provides the parameters water temperature, salinity, dissolved oxygen and chlorophyll-a fluorescence. There is a longer data gap between November 2002 and August 2003 in the time series due to a change of the vessel in October 2002. The data are available at doi:10.1594/PANGAEA.883824 and as part of the COSYNA data portal CODM at http://codm.hzg.de/codm or doi:10.17616/R3K02T. %0 journal article %@ 0022-3670 %A Umlauf, L., Holtermann, P.L., Gillner, C.A., Prien, R.D., Merckelbach, L., Carpenter, J.R. %D 2018 %J Journal of Physical Oceanography %N 8 %P 1731-1747 %R doi:10.1175/JPO-D-18-0018.1 %T Diffusive Convection under Rapidly Varying Conditions %U https://doi.org/10.1175/JPO-D-18-0018.1 8 %X In most observations of diffusive convection in the ocean and in lakes, the characteristic diffusive staircases evolve over long time scales under quasi-stationary background conditions. In the Baltic Sea, however, diffusive staircases develop inside the flanks of intermittent intrusions that induce strong inverse temperature gradients over a vertical range of a few meters, varying on time scales of hours to days. Here, results are discussed from an extensive field campaign conducted in summer 2016 in the southern Baltic Sea, including temperature microstructure data from ocean gliders and an autonomous profiling platform. We find conditions favorable for diffusive instability in the vicinity of warm and cold intrusions with density ratios as small as Rρ = 1.3. The staircases evolving under these conditions are characterized by a small number of steps (typically 1–4) with order 0.1–1-m thickness, temperature differences exceeding 1 K across individual diffusive interfaces, and exceptionally large diffusive heat fluxes of order 10 W m−2. The standard heat flux parameterization of Kelley agrees within a factor of 2 with the directly observed interfacial heat fluxes, except for large fluxes at low Rρ, which are strongly overestimated. The glider surveys reveal a surprisingly small lateral coherency of order 100 m of the staircase patterns, and a spreading of the diffusively unstable intrusions across isopycnals. %0 journal article %@ 2296-7745 %A Carlson, D.F., Özgökmen, T., Novelli, G., Guigand, C., Chang, H., Fox-Kemper, B., Mensa, J., Mehta, S., Fredj, E., Huntley, H., Kirwan, A.D., Berta, M., Rebozo, M., Curcic, M., Ryan, E., Lund, B., Haus, B., Molemaker, J., Hunt, C., Chen, S., Bracken, L., Horstmann, J. %D 2018 %J Frontiers in Marine Science %P 478 %R doi:10.3389/fmars.2018.00479 %T Surface Ocean Dispersion Observations From the Ship-Tethered Aerostat Remote Sensing System %U https://doi.org/10.3389/fmars.2018.00479 %X Oil slicks and sheens reside at the air-sea interface, a region of the ocean that is notoriously difficult to measure. Little is known about the velocity field at the sea surface in general, making predictions of oil dispersal difficult. The Ship-Tethered Aerostat Remote Sensing System (STARSS) was developed to measure Lagrangian velocities at the air-sea interface by tracking the transport and dispersion of bamboo dinner plates in the field of view of a high-resolution aerial imaging system. The camera had a field of view of approximately 300 × 200 m and images were obtained every 15 s over periods of up to 3 h. A series of experiments were conducted in the northern Gulf of Mexico in January-February 2016. STARSS was equipped with a GPS and inertial navigation system (INS) that was used to directly georectify the aerial images. A relative rectification technique was developed that translates and rotates the plates to minimize their total movement from one frame to the next. Rectified plate positions were used to quantify scale-dependent dispersion by computing relative dispersion, relative diffusivity, and velocity structure functions. STARSS was part of a nested observational framework, which included deployments of large numbers of GPS-tracked surface drifters from two ships, in situ ocean measurements, X-band radar observations of surface currents, and synoptic maps of sea surface temperature from a manned aircraft. Here we describe the STARSS system and image analysis techniques, and present results from an experiment that was conducted on a density front that was approximately 130 km offshore. These observations are the first of their kind and the methodology presented here can be adopted into existing and planned oceanographic campaigns to improve our understanding of small-scale and high-frequency variability at the air-sea interface and to provide much-needed benchmarks for numerical simulations. %0 journal article %@ 1424-8220 %A Sticklus, J., Hieronymi, M., Hoeher, P.A. %D 2018 %J Sensors %N 11 %P 3710 %R doi:10.3390/s18113710 %T Effects and Constraints of Optical Filtering on Ambient Light Suppression in LED-Based Underwater Communications %U https://doi.org/10.3390/s18113710 11 %X Optical communication promises to be a high-rate supplement for acoustic communication in short-range underwater applications. In the photic zone of oceanic and coastal waters, underwater optical communication systems are exposed by remaining sunlight. This ambient light generates additional noise in photodetectors, thus degrading system performance. This effect can be diminished by the use of optical filters. This paper investigates light field characteristics of different water types and potential interactions with optical underwater communication. A colored glass and different thin film bandpass filters are examined as filter/detector combinations under varying light and water conditions, and their physical constraints are depicted. This is underlined by various spectral measurements as well as optical signal-to-noise ratio calculations. The importance of matching the characteristics of the light emitting diode (LED) light source, the photodetector, and the filter on the ambient conditions using wider angle of incidents is emphasized. %0 journal article %@ 0025-3324 %A Özgökmen, T., Boufadel, M., Carlson, D., Cousin, C., Guigand, C., Haus, B., Horstmann, J., Lund, B., Molemaker, J., Novelli, G. %D 2018 %J Marine Technology Society Journal %N 6 %P 71-76 %R doi:10.4031/MTSJ.52.6.11 %T Technological Advances for Ocean Surface Measurements by the Consortium for Advanced Research on Transport of Hydrocarbons in the Environment (CARTHE) %U https://doi.org/10.4031/MTSJ.52.6.11 6 %X Formed in the aftermath of the Deepwater Horizon event, the largest accidental marine oil spill, the Consortium for Advanced Research on Transport of Hydrocarbons in the Environment (CARTHE) focused on understanding the physical processes controlling the transport of material from a deep blowout all the way to the coast. Even though CARTHE was initially a modeling-oriented team, it progressively became more focused on observations in order to collect the data needed for model evaluation. A number of new technological advances needed to be made to collect the necessary data. This article reviews most of these, with special focus on surface sampling, where much of the oil is located during oil spills, as well as the measurement of near-field droplet size distribution. %0 journal article %@ 2296-7745 %A Pakhomova, S., Yakushev, E., Protsenko, E., Rigaud, S., Cossa, D., Knoery, J., Couture, R., Radakovitch, O., Yakubov, S., Krzeminska, D., Newton, A. %D 2018 %J Frontiers in Marine Science %P 291 %R doi:10.3389/fmars.2018.00291 %T Modeling the Influence of Eutrophication and Redox Conditions on Mercury Cycling at the Sediment-Water Interface in the Berre Lagoon %U https://doi.org/10.3389/fmars.2018.00291 %X This study presents a specifically designed Mercury module in a coupled benthic-pelagic reactive-transport model - Bottom RedOx Model (BROM) that allows to study mercury (Hg) biogeochemistry under different conditions. This module considers the transformation of elemental mercury (Hg(0)), divalent mercury (Hg(II)) and methylmercury (MeHg). The behavior of mercury species in the model is interconnected with changes of oxygen, hydrogen sulfide, iron oxides, organic matter, and biota. We simulated the transformation and transport of Hg species in the water column and upper sediment layer under five different scenarios, combining various levels of oxygenation and trophic state in the Berre lagoon, a shallow eutrophic lagoon of the French Mediterranean coast subjected to seasonal anoxia. The first scenario represents the conditions in the lagoon that are compared with experimental data. The four other scenarios were produced by varying the biological productivity, using low and high nutrient (N and P) concentrations, and by varying the redox conditions using different intensity of vertical mixing in the water column. The results of the simulation show that both oxidized and reduced sediments can accumulate Hg, but any shifts in redox conditions in bottom water and upper sediment layer lead to the release of Hg species into the water column. Eutrophication and/or restricted vertical mixing lead to reducing conditions and intensify MeHg formation in the sediment with periodic release to the water column. Oxygenation of an anoxic water body can lead to the appearance of Hg species in the water column and uptake by organisms, whereby Hg may enter into the food web. The comparison of studied scenarios shows that a well-oxygenated eutrophic system favors the conditions for Hg species bioaccumulation with a potential adverse effect on the ecosystem. The research is relevant to the UN Minimata convention, EU policies on water, environmental quality standards and Mercury in particular. %0 journal article %@ 2076-3417 %A Zielinski, O., Rüssmeier, N., Ferdinand, O., Miranda, M., Wollschläger, J. %D 2018 %J Applied Sciences %N 12 %P 2685 %R doi:10.3390/app8122685 %T Assessing Fluorescent Organic Matter in Natural Waters: Towards In Situ Excitation–Emission Matrix Spectroscopy %U https://doi.org/10.3390/app8122685 12 %X Natural organic matter (NOM) is a key parameter in aquatic biogeochemical processes. Part of the NOM pool exhibits optical properties, namely absorption and fluorescence. The latter is frequently utilized in laboratory measurements of its dissolved fraction (fluorescent dissolved organic matter, FDOM) through excitation–emission matrix spectroscopy (EEMS). We present the design and field application of a novel EEMS sensor system applicable in situ, the ‘Kallemeter’. Observations are based on a field campaign, starting in Norwegian coastal waters entering the Trondheimsfjord. Comparison against the bulk fluorescence of two commercial FDOM sensors exhibited a good correspondence of the different methods and the ability to resolve gradients and dynamics along the transect. Complementary laboratory EEM spectra measurements of surface water samples and their subsequent PARAFAC analysis revealed three dominant components while the ‘Kallemeter’ EEMS sensor system was able to produce reasonable EEM spectra in high DOM concentrated water bodies, yet high noise levels must be addressed in order to provide comparable PARAFAC components. Achievements and limitations of this proof-of-concept are discussed providing guidance towards full in situ EEMS measurements to resolve rapid changes and processes in natural waters based on the assessment of spectral properties. Their combination with multiwavelength FDOM sensors onboard autonomous platforms will enhance our capacities in observing biogeochemical processes in the marine environment in spatiotemporal and spectral dimensions. %0 journal article %@ 0739-0572 %A Støle-Hentschel, S., Seemann, J., Borge, J., Trulsen, K. %D 2018 %J Journal of Atmospheric and Oceanic Technology %N 6 %P 1201-1220 %R doi:10.1175/JTECH-D-17-0145.1 %T Consistency between Sea Surface Reconstructions from Nautical X-Band Radar Doppler and Amplitude Measurements %U https://doi.org/10.1175/JTECH-D-17-0145.1 6 %X This study comprises the analysis and the interpretation of the coherent and the noncoherent parts of a coherent-on-receive microwave radar at grazing incidence conditions. The Doppler measurement is an extension of standard civil marine radar technology. While intensity images require interpretation based on understanding the underlying imaging mechanism, the Doppler signal measures the motion of an area of sea surface and is therefore closely related to the wave physics. Both the measured Doppler signal and the backscatter intensity signal are suitable for surface inversion and give almost identical surface elevations. A statistical comparison with a nearby buoy showed good correlation for the significant wave height and the peak period. By comparing the Doppler signal and the amplitude in the backscatter, the study amends the understanding of imaging mechanisms in marine radars at grazing incidence. %0 journal article %@ 0003-6935 %A Lefering, I., Roettgers, R., Utschig, C., McKee, D. %D 2017 %J Applied Optics %N 22 %P 6357-6366 %R doi:10.1364/AO.56.006357 %T Uncertainty budgets for liquid waveguide CDOM absorption measurements %U https://doi.org/10.1364/AO.56.006357 22 %X Long path length liquid waveguide capillary cell (LWCC) systems using simple spectrometers to determine the spectral absorption by colored dissolved organic matter (CDOM) have previously been shown to have better measurement sensitivity compared to high-end spectrophotometers using 10 cm cuvettes. Information on the magnitude of measurement uncertainties for LWCC systems, however, has remained scarce. Cross-comparison of three different LWCC systems with three different path lengths (50, 100, and 250 cm) and two different cladding materials enabled quantification of measurement precision and accuracy, revealing strong wavelength dependency in both parameters. Stable pumping of the sample through the capillary cell was found to improve measurement precision over measurements made with the sample kept stationary. Results from the 50 and 100 cm LWCC systems, with higher refractive index cladding, showed systematic artifacts including small but unphysical negative offsets and high-frequency spectral perturbations due to limited performance of the salinity correction. In comparison, the newer 250 cm LWCC with lower refractive index cladding returned small positive offsets that may be physically correct. After null correction of measurements at 700 nm, overall agreement of CDOM absorption data at 440 nm was found to be within 5% root mean square percentage error. %0 conference lecture %@ %A Ruescas, A.B., Hieronymi, M., Koponen, S., Kallio, K., Camps-Valls, G. %D 2017 %J IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2017 %T Retrieval of coloured dissolved organic matter with machine learing methods %U %X %0 journal article %@ 2169-9275 %A Shibley, N.C., Timmermans, M.-L., Carpenter, J.R., Toole, J.M. %D 2017 %J Journal of Geophysical Research : Oceans %N 2 %P 980-994 %R doi:10.1002/2016JC012419 %T Spatial variability of the Arctic Ocean's double-diffusive staircase %U https://doi.org/10.1002/2016JC012419 2 %X The Arctic Ocean thermohaline stratification frequently exhibits a staircase structure overlying the Atlantic Water Layer that can be attributed to the diffusive form of double-diffusive convection. The staircase consists of multiple layers of O(1) m in thickness separated by sharp interfaces, across which temperature and salinity change abruptly. Through a detailed analysis of Ice-Tethered Profiler measurements from 2004 to 2013, the double-diffusive staircase structure is characterized across the entire Arctic Ocean. We demonstrate how the large-scale Arctic Ocean circulation influences the small-scale staircase properties. These staircase properties (layer thicknesses and temperature and salinity jumps across interfaces) are examined in relation to a bulk vertical density ratio spanning the staircase stratification. We show that the Lomonosov Ridge serves as an approximate boundary between regions of low density ratio (approximately 3–4) on the Eurasian side and higher density ratio (approximately 6–7) on the Canadian side. We find that the Eurasian Basin staircase is characterized by fewer, thinner layers than that in the Canadian Basin, although the margins of all basins are characterized by relatively thin layers and the absence of a well-defined staircase. A double-diffusive 4/3 flux law parametrization is used to estimate vertical heat fluxes in the Canadian Basin to be O(0.1) W m−2. It is shown that the 4/3 flux law may not be an appropriate representation of heat fluxes through the Eurasian Basin staircase. Here molecular heat fluxes are estimated to be between O(0.01) and O(0.1) W m−2. However, many uncertainties remain about the exact nature of these fluxes. %0 journal article %@ 1812-0784 %A Eschenbach, C.A. %D 2017 %J Ocean Science %N 1 %P 161-173 %R doi:10.5194/os-13-161-2017 %T Bridging the Gap between Observational Oceanography and Users %U https://doi.org/10.5194/os-13-161-2017 1 %X The stakeholder interaction is integrated into the COSYNA product life cycle outlined here and the steps undertaken are exemplified for the product Surface Current Fields in the German Bight. Initial surveys revealed COSYNA's potential relevance in the national and international context. After the technological and mathematical realization of high-quality parameter fields, external experts evaluated the scientific value, informational value, innovative leap, cost/benefit aspects, operability, etc., of the data products. In order to improve products and their usability and to pave the way for future co-operation, interviews and workshops with potential users from the offshore wind energy industry were conducted. The stakeholder interaction process was successful, revealing relevant insights into user demands and usability of (possible) products. Analysis of data download provided some evidence for impact beyond academia. Other criteria for the increasingly demanded evaluation of the impact of coastal research are discussed. By sharing first-hand experiences, this study contributes to the emerging knowledge on integration of science and end users. %0 journal article %@ 1812-0784 %A Carrasco, R., Stresser, M., Horstmann, J. %D 2017 %J Ocean Science %N 1 %P 95-103 %R doi:10.5194/os-13-95-2017 %T A Simple Method for Retrieving Significant Wave Height from Dopplerized X-Band Radar %U https://doi.org/10.5194/os-13-95-2017 1 %X Retrieving spectral wave parameters such as the peak wave direction and wave period from marine radar backscatter intensity is very well developed. However, the retrieval of significant wave height is difficult because the radar image spectrum (a backscatter intensity variance spectrum) has to be transferred to a wave spectrum (a surface elevation variance spectrum) using a modulation transfer function (MTF) which requires extensive calibration for each individual radar setup. In contrast to the backscatter intensity, the Doppler velocity measured by a coherent radar is induced by the radial velocity of the surface scattering and its periodic component is mainly the contribution of surface waves. Therefore, the variance of the Doppler velocity can be utilized to retrieve the significant wave height. Analysing approximately 100 days of Doppler velocity measurements of a coherent on receive radar operating at X-band with vertical polarization in transmit and receive, a simple relation was derived and validated to retrieve significant wave heights. Comparison to wave measurements of a wave rider buoy as well as an acoustic wave and current profiler resulted in a root mean square error of 0.24 m with a bias of 0.08 m. Furthermore, the different sources of error are discussed and investigated. %0 journal article %@ 1812-0784 %A Onken, R. %D 2017 %J Ocean Science %N 2 %P 235-257 %R doi:10.5194/os-13-235-2017 %T Validation of an ocean shelf model for the prediction of mixed-layer properties in the Mediterranean Sea west of Sardinia %U https://doi.org/10.5194/os-13-235-2017 2 %X The Regional Ocean Modeling System (ROMS) has been employed to explore the sensitivity of the forecast skill of mixed-layer properties to initial conditions, boundary conditions, and vertical mixing parameterisations. The initial and lateral boundary conditions were provided by the Mediterranean Forecasting System (MFS) or by the MERCATOR global ocean circulation model via one-way nesting; the initial conditions were additionally updated through the assimilation of observations. Nowcasts and forecasts from the weather forecast models COSMO-ME and COSMO-IT, partly melded with observations, served as surface boundary conditions. The vertical mixing was parameterised by the GLS (generic length scale) scheme Umlauf and Burchard (2003) in four different set-ups. All ROMS forecasts were validated against the observations which were taken during the REP14-MED survey to the west of Sardinia. Nesting ROMS in MERCATOR and updating the initial conditions through data assimilation provided the best agreement of the predicted mixed-layer properties with the time series from a moored thermistor chain. Further improvement was obtained by the usage of COSMO-ME atmospheric forcing, which was melded with real observations, and by the application of the k-ω vertical mixing scheme with increased vertical eddy diffusivity. The predicted temporal variability of the mixed-layer temperature was reasonably well correlated with the observed variability, while the modelled variability of the mixed-layer depth exhibited only agreement with the observations near the diurnal frequency peak. For the forecasted horizontal variability, reasonable agreement was found with observations from a ScanFish section, but only for the mesoscale wave number band; the observed sub-mesoscale variability was not reproduced by ROMS. %0 journal article %@ 2296-7745 %A Bracher, A., Bouman, H.A., Brewin, R.J.W., Bricaud, A., Brotas, V., Ciotti, A.M., Clementson, L., Devred, E., Di Cicco, A., Dutkiewicz, S., Hardman-Mountford, N.J., Hickman, A.E., Hieronymi, M., Hirata, T., Losa, S.N., Mouw, C.B., Organelli, E., Raitsos, D.E., Uitz, J., Vogt, M., Wolanin, A. %D 2017 %J Frontiers in Marine Science %P 55 %R doi:10.3389/fmars.2017.00055 %T Obtaining Phytoplankton Diversity from Ocean Color: A Scientific Roadmap for Future Development %U https://doi.org/10.3389/fmars.2017.00055 %X To improve our understanding of the role of phytoplankton for marine ecosystems and global biogeochemical cycles, information on the global distribution of major phytoplankton groups is essential. Although algorithms have been developed to assess phytoplankton diversity from space for over two decades, so far the application of these data sets has been limited. This scientific roadmap identifies user needs, summarizes the current state of the art, and pinpoints major gaps in long-term objectives to deliver space-derived phytoplankton diversity data that meets the user requirements. These major gaps in using ocean color to estimate phytoplankton community structure were identified as: (a) the mismatch between satellite, in situ and model data on phytoplankton composition, (b) the lack of quantitative uncertainty estimates provided with satellite data, (c) the spectral limitation of current sensors to enable the full exploitation of backscattered sunlight, and (d) the very limited applicability of satellite algorithms determining phytoplankton composition for regional, especially coastal or inland, waters. Recommendation for actions include but are not limited to: (i) an increased communication and round-robin exercises among and within the related expert groups, (ii) the launching of higher spectrally and spatially resolved sensors, (iii) the development of algorithms that exploit hyperspectral information, and of (iv) techniques to merge and synergistically use the various streams of continuous information on phytoplankton diversity from various satellite sensors' and in situ data to ensure long-term monitoring of phytoplankton composition. %0 journal article %@ 0024-3590 %A Fischer, S.J., York, J.K., Voynova, Y.G., Ullman, W.J. %D 2017 %J Limnology and Oceanography %N 2 %P 408-420 %R doi:10.1002/lno.10398 %T Distance-based mixing models of δ18 NNO3− and δ18 ONO3− in a marsh-lined estuary with multiple, distinct NO3− sources (Murderkill Estuary, Delaware, USA) %U https://doi.org/10.1002/lno.10398 2 %X The Murderkill Estuary (Delaware, USA) receives principally from its upland watershed and from a wastewater treatment facility. Due to disparate sources, one-dimensional salinity-based mixing models were inadequate for describing distributions of , δ15 , and δ18 . Distance-based mixing models with multiple, spatially-specified inputs were, therefore, applied to describe conservative mixing of these constituents and determine the extent to which biogeochemical reactions lead to non-conservative behavior of . These models closely matched Si observations in both winter and summer, consistent with high wastewater silicate loads and light limitation, and serve to validate modeling parameters for both seasons. A close fit of distance-based models to estuarine observations suggested a lack of uptake and fractionation in early winter. In the summer, modeled predictions of , δ15 , and δ18 diverged from estuarine observations, particularly in the oligohaline and polyhaline regions, consistent with in situ nitrogen cycling or additional sources and sinks. Effluent from an adjacent marsh in the lower estuary contained with low δ15 and δ18ONO3, low DO and high concentrations in late summer. This data and previous studies of adjacent Delaware Bay suggest that reactions in marshes and Bay waters likely drove the non-conservative behavior of and its stable isotopes. Potential uncertainty in watershed discharge, however, limited explicit quantitation of loss in the estuary. Nonetheless, distance-based models are useful tools for the study of , δ15 and δ18 distributions and cycling patterns in complex marsh-lined estuaries with multiple inputs. %0 journal article %@ 1726-4170 %A Voynova, Y.G., Brix, H., Petersen, W., Weigelt-Krenz, S., Scharfe, M. %D 2017 %J Biogeosciences %N 3 %P 541-557 %R doi:10.5194/bg-14-541-2017 %T Extreme Flood Impact on Estuarine and Coastal Biogeochemistry: the 2013 Elbe Flood %U https://doi.org/10.5194/bg-14-541-2017 3 %X German Bight in the summer. %0 journal article %@ 2296-7745 %A Hieronymi, M., Mueller, D., Doerffer, R. %D 2017 %J Frontiers in Marine Science %P 140 %R doi:10.3389/fmars.2017.00140 %T The OLCI Neural Network Swarm (ONNS): A Bio-Geo-Optical Algorithm for Open Ocean and Coastal Waters %U https://doi.org/10.3389/fmars.2017.00140 %X The processing scheme of a novel in-water algorithm for the retrieval of ocean color products from Sentinel-3 OLCI is introduced. The algorithm consists of several blended neural networks that are specialized for 13 different optical water classes. These comprise clearest natural waters but also waters reaching the frontiers of marine optical remote sensing, namely extreme absorbing, or scattering waters. Considered chlorophyll concentrations reach up to 200 mg m−3, non-algae particle concentrations up to 1,500 g m−3, and the absorption coefficient of colored dissolved organic matter at 440 nm is up to 20 m−1. The algorithm generates different concentrations of water constituents, inherent and apparent optical properties, and a color index. In addition, all products are delivered with an uncertainty estimate. A baseline validation of the products is provided for various water types. We conclude that the algorithm is suitable for the remote sensing estimation of water properties and constituents of most natural waters. %0 journal article %@ 1812-0784 %A Baschek, B., Schroeder, F., Brix, H., Riethmueller, R., Badewien, T.H., Breitbach, G., Bruegge, B., Colijn, F., Doerffer, R., Eschenbach, C., Friedrich, J., Fischer, P., Garthe, S., Horstmann, J., Krasemann, H., Metfies, K., Ohle, N., Petersen, W., Proefrock, D., Roettgers, R., Schlueter, M., Schulz, J., Schulz-Stellenfleth, J., Stanev, E., Winter, C., Wirtz, K., Wollschlaeger, J., Zielinski, O., Ziemer, F. %D 2017 %J Ocean Science %N 3 %P 379-410 %R doi:10.5194/os-13-379-2017 %T The Coastal Observing System for Northern and Arctic Seas (COSYNA) %U https://doi.org/10.5194/os-13-379-2017 3 %X The COSYNA automated observing and modelling system is designed to monitor real-time conditions and provide short-term forecasts, data, and data products to help assess the impact of anthropogenically induced change. Observations are carried out by combining satellite and radar remote sensing with various in situ platforms. Novel sensors, instruments, and algorithms are developed to further improve the understanding of the interdisciplinary interactions between physics, biogeochemistry, and the ecology of coastal seas. New modelling and data assimilation techniques are used to integrate observations and models in a quasi-operational system providing descriptions and forecasts of key hydrographic variables. Data and data products are publicly available free of charge and in real time. They are used by multiple interest groups in science, agencies, politics, industry, and the public. %0 journal article %@ 0143-1161 %A Karimova, S. %D 2017 %J International Journal of Remote Sensing %N 6 %P 1642-1664 %R doi:10.1080/01431161.2017.1285078 %T Observations of asymmetric turbulent stirring in inner and marginal seas using satellite imagery %U https://doi.org/10.1080/01431161.2017.1285078 6 %X For the open ocean, it was already reported on the cyclonic (anticyclonic) asymmetry of appearance of eddies of a certain spatial scale. In this article, we scrutinize the ratios of mostly mesoscale cyclonic and anticyclonic eddies in a number of inner and marginal marine basins, namely in the Baltic, Black, North, and Western Mediterranean Seas. As research material, over 9700 eddy manifestations in the thermal infrared, visible-range, and radar satellite imagery were used. The analysis performed showed that in all the seas the typical and average values of the diameter of anticyclonic eddies were greater than those of cyclonic eddies. The main factor that defines the ratio between anticyclonic and cyclonic eddies in the basins under consideration was discovered to be the intensity of their surface currents. Thus, in the presence of a strong jet flow at the scales of about 2–4 baroclinic Rossby radii, the cyclonic eddy dominance typical for smaller eddies was replaced by the anticyclonic one. If strong jet streams were missing, as that typical of the Baltic Sea, cyclonic eddies were prevailing over the entire spectrum of eddy diameters. %0 journal article %@ 1812-0784 %A Hemming, M.P., Kaiser, J., Heywood, K.J., Bakker, D.C.E., Boutin, J., Shitashima, K., Lee, G., Legge, O., Onken, R. %D 2017 %J Ocean Science %N 3 %P 427-442 %R doi:10.5194/os-13-427-2017 %T Measuring pH variability using an experimental sensor on an underwater glider %U https://doi.org/10.5194/os-13-427-2017 3 %X Autonomous underwater gliders offer the capability of measuring oceanic parameters continuously at high resolution in both vertical and horizontal planes, with timescales that can extend to many months. An experimental ion-sensitive field-effect transistor (ISFET) sensor measuring pH on the total scale was attached to a glider during the REP14-MED experiment in June 2014 in the Sardinian Sea in the northwestern Mediterranean. During the deployment, pH was sampled at depths of up to 1000 m along an 80 km transect over a period of 12 days. Water samples were collected from a nearby ship and analysed for dissolved inorganic carbon concentration and total alkalinity to derive the pH for validating the ISFET sensor measurements. The vertical resolution of the pH sensor was good (1 to 2 m), but stability was poor and the sensor drifted in a non-monotonous fashion. In order to remove the sensor drift, a depth-constant time-varying offset was applied throughout the water column for each dive, reducing the spread of the data by approximately two-thirds. Furthermore, the ISFET sensor required temperature- and pressure-based corrections, which were achieved using linear regression. Correcting for this decreased the apparent sensor pH variability by a further 13 to 31 %. Sunlight caused an apparent sensor pH decrease of up to 0.1 in surface waters around local noon, highlighting the importance of shielding the sensor from light in future deployments. The corrected pH from the ISFET sensor is presented along with potential temperature, salinity, potential density anomalies (σθ), and dissolved oxygen concentrations (c(O2)) measured by the glider, providing insights into the physical and biogeochemical variability in the Sardinian Sea. The pH maxima were identified close to the depth of the summer chlorophyll maximum, where high c(O2) values were also found. Longitudinal pH variations at depth (σθ > 28. 8 kg m−3) highlighted the variability of water masses in the Sardinian Sea. Higher pH was observed where salinity was  > 38. 65, and lower pH was found where salinity ranged between 38.3 and 38.65. The higher pH was associated with saltier Levantine Intermediate Water, and it is possible that the lower pH was related to the remineralisation of organic matter. Furthermore, shoaling isopycnals closer to shore coinciding with low pH and c(O2), high salinity, alkalinity, dissolved inorganic carbon concentrations, and chlorophyll fluorescence waters may be indicative of upwelling. %0 journal article %@ 1094-4087 %A Tan, H., Oishi, T., Tanaka, A., Doerffer, R., Tan, Y. %D 2017 %J Optics express %N 12 %P A564-A573 %R doi:10.1364/OE.25.00A564 %T Chlorophyll-a specific volume scattering function of phytoplankton %U https://doi.org/10.1364/OE.25.00A564 12 %X Chlorophyll-a specific light volume scattering functions (VSFs) by cultured phytoplankton in visible spectrum range is presented. Chlorophyll-a specific VSFs were determined based on the linear least squares method using a measured VSFs with different chlorophyll-a concentrations. We found obvious variability of it in terms of spectral and angular shapes of VSF between cultures. It was also presented that chlorophyll-a specific scattering significantly affected on spectral variation of the remote sensing reflectance, depending on spectral shape of b. This result is useful for developing an advance algorithm of ocean color remote sensing and for deep understanding of light in the sea. %0 preprint %@ 1991-9611 %A Yakubov, S., Wallhead, P., Protsenko, E., Yakushev, E. %D 2017 %J Geoscientific Model Development Discussions %P 299 %R doi:10.5194/gmd-2017-299 %T A1-Dimensional Ice-Pelagic-Benthic transport model (IPBM) v0.1: Coupled simulation of ice, water column, and sediment biogeochemistry %U https://doi.org/10.5194/gmd-2017-299 %X Aquatic biogeochemical processes can strongly interact, especially in polar regions, with processes occurring in adjacent ice and sediment layers, yet there are few modelling tools to simulate these systems in a fully coupled manner. We developed a 1-Dimensional Ice-Pelagic-Benthic transport model (IPBM) for coupled simulation of ice, water column, and upper sediment biogeochemistry. IPBM describes the processes of diffusion and particle sinking in both ice and water, as well sedimentation and bioturbation processes in the sediments. To describe ice, pelagic, and benthic biogeochemical dynamics (reaction terms), IPBM was partly coupled to the European Regional Seas Ecosystem Model (ERSEM) and partly to the Bottom RedOx Model biogeochemistry module (BROM-biogeochemistry) using the Framework for Aquatic Biogeochemical Models (FABM). To test the coupled system, hydrophysical forcing for a site in the Kara Sea area from a Regional Oceanic Modeling System (ROMS) simulation was used. The test run showed reasonable results for all main variables. IPBM reproduces the ice algae bloom in July followed by a pelagic phytoplankton bloom in August–September, as well as seasonal variability of nutrients in the water column. %0 conference paper %@ %A Ruescas, A.B., Hieronymi, M., Koponen, S., Kallio, K., Camps-Valls, G. %D 2017 %J Proceedings of IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2017 %P 2187-2190 %R doi:10.1109/IGARSS.2017.8127421 %T Retrieval of coloured dissolved organic matter with machine learing methods %U https://doi.org/10.1109/IGARSS.2017.8127421 %X The coloured dissolved organic matter (CDOM) concentration is the standard measure of humic substance in natural waters. CDOM measurements by remote sensing is calculated using the absorption coefficient (a) at a certain wavelength (e.g. ≈ 440nm). This paper presents a comparison of four machine learning methods for the retrieval of CDOM from remote sensing signals: regularized linear regression (RLR), random forest (RF), kernel ridge regression (KRR) and Gaussian process regression (GPR). Results are compared with the established polynomial regression algorithms. RLR is revealed as the simplest and most efficient method, followed closely by its nonlinear counterpart KRR. %0 journal article %@ 0022-3670 %A Carpenter, J.R., Guha, A., Heifetz, E. %D 2017 %J Journal of Physical Oceanography %N 6 %P 1441-1455 %R doi:10.1175/JPO-D-16-0206.1 %T A Physical Interpretation of the Wind-Wave Instability as Interacting Waves %U https://doi.org/10.1175/JPO-D-16-0206.1 6 %X One mechanism for the growth of ocean surface waves by wind is through a shear instability that was first described by Miles in 1957. A physical interpretation of this wind-wave instability is provided in terms of the interaction of the surface gravity wave with perturbations of vorticity within the critical layer—a near-singularity in the airflow where the background flow speed matches that of the surface gravity wave. This physical interpretation relies on the fact that the vertical velocity field is slowly varying across the critical layer, whereas both the displacement and vorticity fields vary rapidly. Realizing this allows for the construction of a physically intuitive description of the critical layer vorticity perturbations that may be approximated by a simple vortex sheet model, the essence of the wind-wave instability can then be captured through the interaction of the critical layer vorticity with the surface gravity wave. This simple model is then extended to account for vorticity perturbations in the airflow profile outside of the critical layer and is found to lead to an exact description of the linear stability problem that is also computationally efficient. The interpretation allows, in general, for the incorporation of sheared critical layers into the “wave interaction theory” that is commonly used to provide a physical description and rationalization of results in the stability of stratified shear flows. %0 journal article %@ 0079-6611 %A Floeter, J., Beusekom, J.E.E.van, Auch, D., Callies, U., Carpenter, J., Dudeck, T., Eberle, S., Eckhardt, A., Gloe, D., Haenselmann, K., Hufnagl, M., Janssen, S., Lenhart, H., Moeller, K.O., North, R.P., Pohlmann, T., Riethmueller, R., Schulz, S., Spreizenbarth, S., Temming, A., Walter, B., Zielinski, O., Moellmann, C. %D 2017 %J Progress in Oceanography %P 154-173 %R doi:10.1016/j.pocean.2017.07.003 %T Pelagic effects of offshore wind farm foundations in the stratified North Sea %U https://doi.org/10.1016/j.pocean.2017.07.003 %X A recent increase in the construction of Offshore Wind Farms (OWFs) has initiated numerous environmental impact assessments and monitoring programs. These focus on sea mammals, seabirds, benthos or demersal fish, but generally ignore any potential effects OWFs may have on the pelagic ecosystem. The only work on the latter has been through modelling analyses, which predict localised impacts like enhanced vertical mixing leading to a decrease in seasonal stratification, as well as shelf-wide changes of tidal amplitudes. Here we provide for the first-time empirical bio-physical data from an OWF. The data were obtained by towing a remotely operated vehicle (TRIAXUS ROTV) through two non-operating OWFs in the summer stratified North Sea. The undulating TRIAXUS transects provided high-resolution CTD data accompanied by oxygen and chlorophyll-a measurements. We provide empirical indication that vertical mixing is increased within the OWFs, leading to a doming of the thermocline and a subsequent transport of nutrients into the surface mixed layer (SML). Nutrients were taken up rapidly because underwater photosynthetically active radiation (PAR) enabled net primary production in the entire water column, especially within submesoscale chlorophyll-a pillars that were observed at regular intervals within the OWF regions. Video Plankton Recorder (VPR) images revealed distinct meroplankton distribution patterns in a copepod-dominated plankton community. Hydroacoustic records did not show any OWF effects on the distribution of pelagic fish. The results of a pre-OWF survey show however, that it is difficult to fully separate the anthropogenic impacts from the natural variability. %0 journal article %@ 0723-4864 %A Buckley, M.P., Veron, F. %D 2017 %J Experiments in Fluids %P 161 %R doi:10.1007/s00348-017-2439-2 %T Airflow measurements at a wavy air–water interface using PIV and LIF %U https://doi.org/10.1007/s00348-017-2439-2 %X Physical phenomena at an air–water interface are of interest in a variety of flows with both industrial and natural/environmental applications. In this paper, we present novel experimental techniques incorporating a multi-camera multi-laser instrumentation in a combined particle image velocimetry and laser-induced fluorescence system. The system yields accurate surface detection thus enabling velocity measurements to be performed very close to the interface. In the application presented here, we show results from a laboratory study of the turbulent airflow over wind driven surface waves. Accurate detection of the wavy air–water interface further yields a curvilinear coordinate system that grants practical and easy implementation of ensemble and phase averaging routines. In turn, these averaging techniques allow for the separation of mean, surface wave coherent, and turbulent velocity fields. In this paper, we describe the instrumentation and techniques and show several data products obtained on the air-side of a wavy air–water interface. %0 journal article %@ 2296-7745 %A Martinez-Vicente, V., Evers-King, H., Roy, S., Kostadinov, T.S., Tattan, G.A., Graff, J.R., Brewin, R.J.W., Dall´Òlmo, G., Jackson, T., Hickman, A.E., Roettgers, R., Krasemann, H., Maranon, E., Platt, T., Sathyendranath, S. %D 2017 %J Frontiers in Marine Science %P 378 %R doi:10.3389/fmars.2017.00378 %T Intercomparison of Ocean Color Algorithms for Picophytoplankton Carbon in the Ocean %U https://doi.org/10.3389/fmars.2017.00378 %X The differences among phytoplankton carbon (Cphy) predictions from six ocean color algorithms are investigated by comparison with in situ estimates of phytoplankton carbon. The common satellite data used as input for the algorithms is the Ocean Color Climate Change Initiative merged product. The matching in situ data are derived from flow cytometric cell counts and per-cell carbon estimates for different types of pico-phytoplankton. This combination of satellite and in situ data provides a relatively large matching dataset (N > 500), which is independent from most of the algorithms tested and spans almost two orders of magnitude in Cphy. Results show that not a single algorithm outperforms any of the other when using all matching data. Concentrating on the oligotrophic regions (Chlorophyll-a concentration, B, less than 0.15 mg Chl m−3), where flow cytometric analysis captures most of the phytoplankton biomass, reveals significant differences in algorithm performance. The bias ranges from −35 to +150% and unbiased root mean squared difference from 5 to 10 mg C m−3 among algorithms, with chlorophyll-based algorithms performing better than the rest. The backscattering-based algorithms produce different results at the clearest waters and these differences are discussed in terms of the different algorithms used for optical particle backscattering coefficient (bbp) retrieval. %0 report %@ %A Assmann, S., Atamanchuk, D., Bittig, H., Bresnahan, P., Brown, P., Carlin, G., Comeau, A., Connelly, D., Downing, B., Fassbender, A., Fiedler, B., Gedela, S., Gkritzalis, T., Hannides, A., Hartman, S., Johnson, K., L’ Esperance, C., Loenborg, C., Loucaides, S., Ma, J., Nair, R., Neill, C., Ntoumas, M., Pereira,E., Poteau, A., Rerolle, V., Rigby, P., Schuster, U., Simpson, K., Spaulding, R., Trull, T., Ulfsbo, A., Voynova, Y. %D 2017 %J %T A user’s guide for selected autonomous biogeochemical sensors : An outcome from the 1st International IOCCP Sensors Summer Course – Instrumenting Our Oceans for Better Observations %U %X %0 journal article %@ 0196-2892 %A Carrasco, R., Horstmann, J., Seemann, J. %D 2017 %J IEEE Transactions on Geoscience and Remote Sensing %N 9 %P 5355-5365 %R doi:10.1109/TGRS.2017.2706067 %T Significant Wave Height Measured by Coherent X-Band Radar %U https://doi.org/10.1109/TGRS.2017.2706067 9 %X Significant wave height is one of the most important parameters for characterizing ocean waves and essential for coastal protection, shipping, as well as off shore industry operations. Within this paper, a robust method is introduced for retrieving significant wave heights from Doppler speed measurements acquired with a coherent-on-receive marine radar. The Doppler velocity is caused by the surface scattering in the line of site of the radar. To a huge extent its periodic component is induced by the orbital motions associated with surface waves. The proposed methodology is based on linear wave theory, accounts for projection effects caused by the fixed antenna look direction, and was applied to a coherent-on-receive radar operating at X-band with vertical polarization in transmit and receive. To show the overall performance of the method, a data set consisting of approximately 100 days of radar measurements was analyzed and used to retrieve significant wave heights. Comparisons to wave measurements collected by a wave rider buoy resulted in a root-mean-square (rms) error of 0.21 m and a bias of 0 m without any calibration parameters needed. To further improve the accuracy of significant wave height, a calibration factor needs to be accounted for, which improves the rms error to 0.15 m with a negligible bias of -0.01 m. %0 journal article %@ 2296-7745 %A Rubio, A., Mader, J., Corgnati, L., Mantovani, C., Griffa, A., Novellino, A., Quentin, C., Wyatt, L., Schulz-Stellenfleth, J., Horstmann, J., Lorente, P., Zambianchi, E., Hartnett, M., Fernandes, C., Zervakis, V., Gorringe, P., Melet, A., Puillat, I. %D 2017 %J Frontiers in Marine Science %P 08 %R doi:10.3389/fmars.2017.00008 %T HF Radar Activity in European Coastal Seas: Next Steps toward a Pan-European HF Radar Network %U https://doi.org/10.3389/fmars.2017.00008 %X High Frequency Radar (HFR) is a land-based remote sensing instrument offering a unique insight to coastal ocean variability, by providing synoptic, high frequency and high resolution data at the ocean atmosphere interface. HFRs have become invaluable tools in the field of operational oceanography for measuring surface currents, waves and winds, with direct applications in different sectors and an unprecedented potential for the integrated management of the coastal zone. In Europe, the number of HFR networks has been showing a significant growth over the past 10 years, with over 50 HFRs currently deployed and a number in the planning stage. There is also a growing literature concerning the use of this technology in research and operational oceanography. A big effort is made in Europe toward a coordinated development of coastal HFR technology and its products within the framework of different European and international initiatives. One recent initiative has been to make an up-to-date inventory of the existing HFR operational systems in Europe, describing the characteristics of the systems, their operational products and applications. This paper offers a comprehensive review on the present status of European HFR network, and discusses the next steps toward the integration of HFR platforms as operational components of the European Ocean Observing System, designed to align and integrate Europe's ocean observing capacity for a truly integrated end-to-end observing system for the European coasts. %0 journal article %@ 1812-0784 %A Onken, R. %D 2017 %J Ocean Science %N 6 %P 925-945 %R doi:10.5194/os-13-925-2017 %T Forecast skill score assessment of a relocatable ocean prediction system, using a simplified objective analysis method %U https://doi.org/10.5194/os-13-925-2017 6 %X A relocatable ocean prediction system (ROPS) was employed to an observational data set which was collected in June 2014 in the waters to the west of Sardinia (western Mediterranean) in the framework of the REP14-MED experiment. The observational data, comprising more than 6000 temperature and salinity profiles from a fleet of underwater gliders and shipborne probes, were assimilated in the Regional Ocean Modeling System (ROMS), which is the heart of ROPS, and verified against independent observations from ScanFish tows by means of the forecast skill score as defined by Murphy(1993). A simplified objective analysis (OA) method was utilised for assimilation, taking account of only those profiles which were located within a predetermined time window W. As a result of a sensitivity study, the highest skill score was obtained for a correlation length scale C = 12.5 km, W = 24 h, and r = 1, where r is the ratio between the error of the observations and the background error, both for temperature and salinity. Additional ROPS runs showed that (i) the skill score of assimilation runs was mostly higher than the score of a control run without assimilation, (i) the skill score increased with increasing forecast range, and (iii) the skill score for temperature was higher than the score for salinity in the majority of cases. Further on, it is demonstrated that the vast number of observations can be managed by the applied OA method without data reduction, enabling timely operational forecasts even on a commercially available personal computer or a laptop. %0 journal article %@ 1812-0784 %A Knoll, M., Borrione, I., Fiekas, H.-V., Funk, A., Hemming, M.P., Kaiser, J., Onken, R., Queste, B., Russo, A. %D 2017 %J Ocean Science %N 6 %P 889-904 %R doi:10.5194/os-13-889-2017 %T Hydrography and Circulation West of Sardinia in June 2014 %U https://doi.org/10.5194/os-13-889-2017 6 %X In the frame of the REP14-MED sea trial in June 2014, the hydrography and circulation west of Sardinia, observed by means of gliders, shipborne CTD (conductivity, temperature, depth) instruments, towed devices, and vessel-mounted ADCPs (acoustic doppler current profilers), are presented and compared with previous knowledge. So far, the circulation is not well-known in this area, and the hydrography is subject to long-term changes. Potential temperature, salinity, and potential density ranges as well as core values of the observed water masses were determined. Modified Atlantic Water (MAW), with potential density anomalies below 28.72 kg m−3, showed a salinity minimum of 37.93 at 50 dbar. Levantine Intermediate Water (LIW), with a salinity maximum of about 38.70 at 400 dbar, was observed within a range of 28.72<σΘ/(kg m−3) < 29.10. MAW and LIW showed slightly higher salinities than previous investigations. During the trial, LIW covered the whole area from the Sardinian shelf to 7°15′ E. Only north of 40° N was it tied to the continental slope. Within the MAW, a cold and saline anticyclonic eddy was observed in the southern trial area. The strongest variability in temperature and salinity appeared around this eddy, and in the southwestern part of the domain, where unusually low saline surface water entered the area towards the end of the experiment. An anticyclonic eddy of Winter Intermediate Water was recorded moving northward at 0.014 m s−1. Geostrophic currents and water mass transports calculated across zonal and meridional transects showed a good agreement with vessel-mounted ADCP measurements. Within the MAW, northward currents were observed over the shelf and offshore, while a southward transport of about 1.5 Sv occurred over the slope. A net northward transport of 0.38 Sv across the southern transect decreased to zero in the north. Within the LIW, northward transports of 0.6 Sv across the southern transects were mainly observed offshore, and decreased to 0.3 Sv in the north where they were primarily located over the slope. This presentation of the REP14-MED observations helps to further understand the long-term evolution of hydrography and circulation in the Western Mediterranean, where considerable changes occurred after the Eastern Mediterranean Transient and the Western Mediterranean Transition. %0 journal article %@ 2296-7745 %A Evers-King, H., Martinez-Vicente, V., Brewin, R.J.W., Dall´Òlmo, G., Hickman, A.E., Jackson, T., Kostadinov, T.S., Krasemann, H., Loisel, H., Roettgers, R., Roy, S., Stramski, D., Thomalla, S., Platt, T., Sathyendranath, S. %D 2017 %J Frontiers in Marine Science %P 251 %R doi:10.3389/fmars.2017.00251 %T Validation and Intercomparison of Ocean Color Algorithms for Estimating Particulate Organic Carbon in the Oceans %U https://doi.org/10.3389/fmars.2017.00251 %X Particulate Organic Carbon (POC) plays a vital role in the ocean carbon cycle. Though relatively small compared with other carbon pools, the POC pool is responsible for large fluxes and is linked to many important ocean biogeochemical processes. The satellite ocean-color signal is influenced by particle composition, size, and concentration and provides a way to observe variability in the POC pool at a range of temporal and spatial scales. To provide accurate estimates of POC concentration from satellite ocean color data requires algorithms that are well validated, with uncertainties characterized. Here, a number of algorithms to derive POC using different optical variables are applied to merged satellite ocean color data provided by the Ocean Color Climate Change Initiative (OC-CCI) and validated against the largest database of in situ POC measurements currently available. The results of this validation exercise indicate satisfactory levels of performance from several algorithms (highest performance was observed from the algorithms of Loisel et al., 2002; Stramski et al., 2008) and uncertainties that are within the requirements of the user community. Estimates of the standing stock of the POC can be made by applying these algorithms, and yield an estimated mixed-layer integrated global stock of POC between 0.77 and 1.3 Pg C of carbon. Performance of the algorithms vary regionally, suggesting that blending of region-specific algorithms may provide the best way forward for generating global POC products. %0 journal article %@ 1812-0784 %A Callies, U., Groll, N., Horstmann, J., Kapitza, H., Klein, H., Massmann, S., Schwichtenberg, F. %D 2017 %J Ocean Science %N 5 %P 799-827 %R doi:10.5194/os-13-799-2017 %T Surface drifters in the German Bight: model validation considering windage and Stokes drift %U https://doi.org/10.5194/os-13-799-2017 5 %X The study suggests that the main sources of simulation errors were inaccurate Eulerian currents and lacking representation of sub-grid-scale processes. Substantial model errors often occurred under low wind conditions. A lower limit of predictability (about 3–5 km day−1) was estimated from two drifters that were initially spaced 20 km apart but converged quickly and diverged again after having stayed at a distance of 2 km or less for about 10 days. In most cases, errors in simulated 25 h drifter displacements were of similar order of magnitude. %0 journal article %@ 1545-598X %A Stresser, M., Carrasco, R., Horstmann, J. %D 2017 %J IEEE Geoscience and Remote Sensing Letters %N 11 %P 2027-2031 %R doi:10.1109/LGRS.2017.2749120 %T Video-Based Estimation of Surface Currents Using a Low-Cost Quadcopter %U https://doi.org/10.1109/LGRS.2017.2749120 11 %X Video imagery of surface waves recorded from a small off-the-shelf quadcopter with a self-stabilizing camera gimbal is analyzed to estimate the surface current field. The nadir looking camera acquires a short image sequence, which is geocoded to Universal Transverse Mercator coordinates. The resulting image sequence is used to quantify characteristic parameters (wavelength, period, and direction) of short (0.1-1 m) surface waves in space and time. This opens the opportunity to fit the linear dispersion relation to the data and thus monitor the frequency shift induced by an ambient current. The fitting is performed by applying a spectral energy-based maximization technique in the wavenumber-frequency domain. The current field is compared with measurements acquired by an acoustic Doppler current profiler mounted on a small boat, showing an overall good agreement. The root-mean-square error in current velocity is 0.09 m/s with no bias. %0 journal article %@ 2296-7745 %A Xi, H., Hieronymi, M., Krasemann, H., Roettgers, R. %D 2017 %J Frontiers in Marine Science %P 272 %R doi:10.3389/fmars.2017.00272 %T Phytoplankton Group Identification Using Simulated and In situ Hyperspectral Remote Sensing Reflectance %U https://doi.org/10.3389/fmars.2017.00272 %X In the present study we investigate the bio-geo-optical boundaries for the possibility to identify dominant phytoplankton groups from hyperspectral ocean color data. A large dataset of simulated remote sensing reflectance spectra, Rrs(λ), was used. The simulation was based on measured inherent optical properties of natural water and measurements of five phytoplankton light absorption spectra representing five major phytoplankton spectral groups. These simulated data, named as C2X data, contain more than 105 different water cases, including cases typical for clearest natural waters as well as for extreme absorbing and extreme scattering waters. For the simulation the used concentrations of chlorophyll a (representing phytoplankton abundance), Chl, are ranging from 0 to 200 mg m−3, concentrations of non-algal particles, NAP, from 0 to 1,500 g m−3, and absorption coefficients of chromophoric dissolved organic matter (CDOM) at 440 nm from 0 to 20 m−1. A second, independent, smaller dataset of simulated Rrs(λ) used light absorption spectra of 128 cultures from six phytoplankton taxonomic groups to represent natural variability. Spectra of this test dataset are compared with spectra from the C2X data in order to evaluate to which extent the five spectral groups can be correctly identified as dominant under different optical conditions. The results showed that the identification accuracy is highly subject to the water optical conditions, i.e., contribution of and covariance in Chl, NAP, and CDOM. The identification in the simulated data is generally effective, except for waters with very low contribution by phytoplankton and for waters dominated by NAP, whereas contribution by CDOM plays only a minor role. To verify the applicability of the presented approach for natural waters, a test using in situ Rrs(λ) dataset collected during a cyanobacterial bloom in Lake Taihu (China) is carried out and the approach predicts blue cyanobacteria to be dominant. This fits well with observation of the blue cyanobacteria Microcystis sp. in the lake. This study provides an efficient approach, which can be promisingly applied to hyperspectral sensors, for identifying dominant phytoplankton spectral groups purely based on Rrs(λ) spectra. %0 dataset %@ %A Petersen, W., Reinke, S., Breitbach, G., Thomas, H., Petschatnikov, M., Wehde, H. %D 2017 %J PANGAEA %R doi:10.1594/PANGAEA.883824 %T Ferrybox record of transect Cuxhaven-Harwich 2002-03 to 2005-10 in NetCDF-format %U https://doi.org/10.1594/PANGAEA.883824 %X From 2002 to 2005 a FerryBox system was installed aboard two different ferries traveling between Cuxhaven (GE) and Harwich (UK) on a daily basis. The FerryBox system is an automated flow-through monitoring system for measuring oceanographic and biogeochemical parameters installed on ships of opportunity. The variables were recorded in a time interval of 10-20 seconds corresponding to a spatial resolution of about 100m. The dataset provides the parameters water temperature, salinity, dissolved oxygen and chlorophyll-a fluorescence. There is a longer data gap between November 2002 and August 2003 in the time series due to a change of the vessel in October 2002. %0 dataset %@ %A Riethmüller, R., Flöser, G. %D 2017 %J PANGAEA %R doi:10.1594/PANGAEA.882561 %T Suspended particulate matter concentrations and organic matter fractions from water samples %U https://doi.org/10.1594/PANGAEA.882561 %X This dataset comprises results from filter weights of more than 5000 water samples taken during numerous field surveys between 1998 and 2017 in the Odra Lagoon (German Baltic Sea coast), several parts of the German Wadden Sea, the Exclusive Economic Zone of Germany in the German Bight (Southern North Sea), the Limfjorden (Denmark), the Oosterschelde (The Netherlands) and the Ria de Vigo (Spain). From the filter weights and filtered water volumes the suspended particulate matter concentrations (SPMC) and, in most cases, the fractions of organic matter were determined by combustion of the loaded filters (Loss on Ignition - LoI). Over the years, the laboratory methods and the type of filter (Whatman GF/C glass fibre filter, 47 mm diameter) were kept identical, but the sampling methods were adapted to technical demands, to the specific conditions of the sampling areas and to novel methodological insight. The samples had to undergo a number of quality checks regarding sampling time and co-ordinates and all laboratory processing steps. Depending on which test they passed they were assigned two types of quality flags, for (1) space and time information and (2) for the sample itself. They range from 1 ("good": all tests passed) to 4 ("bad and not correctable"); further, 9 is assigned for cases with missing information of time, latitude/longitude or water pressure. Further, the filter weights were corrected for filter offsets and - when Loss on Ignition was also determined - for losses of structural water. %0 conference paper %@ %A Meyer, B., Isokeit, C., Maehle, E., Baschek, B. %D 2017 %J OCEANS 2017 - Anchorage %P 1-5 %T Using small swarm-capable AUVs for submesoscale eddy measurements in the Baltic Sea %U %X This paper presents an approach using small and swarm-capable autonomous underwater vehicles (AUVs) as flexible measurement devices for observing oceanic submesoscale eddies. The robots equipped with environmental sensors are placed near interesting oceanographic structures to measure the water column along different trajectories. The robots communicate acoustically while diving in a saw tooth pattern underneath the surface. This measurement strategy enables high-resolution sensor data on the one hand and a fast reaction to changing conditions in the observed region on the other hand. %0 dataset %@ %A Carrasco, R., Floeter, J., Horstmann, J. %D 2017 %J PANGAEA %R doi:10.1594/PANGAEA.882329 %T Track of GPS-Drifters from HEINCKE cruise HE490 %U https://doi.org/10.1594/PANGAEA.882329 %X The drifters were deployed within the German Bight of the North Sea from the FS Heincke during cruise HE 490, which was performed between 21. June and 5. July 2017. The utilized drifters obtain their position via the Global Positioning System (GPS) and communicated their locations to the lab via Iridium (a global full ocean coverage bidirectional satellite communication network). Within the experiment, five Albatros drifters MD03i were used. The MD03i is a cylinder shaped drifter, which has a diameter of 0.1 m and a length of 0.32 m, where only approx. 0.08 m are above the water surface when deployed. To enhance the drifters drag a sail was attached 1.0 m below the sea surface. The sails were made of two circular black plastic parts (0.35 m diameter) joined perpendicularly in the center. Due to the very small area above the water surface the drifter path represents the current in the upper meter of the water column. %0 dataset %@ %A Carrasco, R., Floeter, J., Horstmann, J. %D 2017 %J PANGAEA %R doi:10.1594/PANGAEA.882346 %T Track of GPS-Drifters from HEINCKE cruise HE496 %U https://doi.org/10.1594/PANGAEA.882346 %X The drifters were deployed within the German Bight of the North Sea from the FS Heincke during cruise HE 496, which was performed between 14. and 21. September 2017. The utilized drifters obtain their position via the Global Positioning System (GPS) and communicated their locations to the lab via Iridium (a global full ocean coverage bidirectional satellite communication network). Within the experiment, 10 Albatros drifters MD03i were used. The MD03i is a cylinder shaped drifter, which has a diameter of 0.1 m and a length of 0.32 m, where only approx. 0.08 m are above the water surface when deployed. To enhance the drifters drag a sail was attached 1.0 m below the sea surface. The sails were made of two circular black plastic parts (0.35 m diameter) joined perpendicularly in the center. Due to the very small area above the water surface the drifter path represents the current in the upper meter of the water column. %0 journal article %@ 0001-4966 %A Baschek, B., Benavides, I., North, R., Smith, G., Miller, D. %D 2017 %J The Journal of the Acoustical Society of America %P 3545 %R doi:10.1121/1.4987499 %T Submesoscale dynamics in the coastal ocean %U https://doi.org/10.1121/1.4987499 %X High-resolution observations reveal the fast dynamics of submesoscale eddies in the coastal ocean. The eddies seem to play an important role in the ocean energy cascade and are thought to be important drivers for phytoplankton production. The eddies are frequently observed in the coastal and open ocean and are characterized by sharp gradients of 1°C/m and high Rossby numbers >10. In order to simultaneously resolve the short temporal and spatial scales of submesoscale eddies, an observational multi-platform approach with planes, a zeppelin, several vessels, gliders, and floats was used yielding a horizontal and vertical resolution of <1 m with repeat observations every 1 to 15 min. The Submesoscale Experiments (SubEx) took place off Catalina Island, CA, and off Bornholm in the Baltic Sea. Observations were carried out with aerial sea surface temperature and hyperspectral measurements, rapid in situ measurements with a towed instrument array, gliders with turbulence probes, as well as surface and subsurface velocity measurements with drifters, as well as Radar and Acoustic Doppler Current Profilers. Additional SAR, SST, and ocean color satellite imagery is used to investigate the occurrence of submesoscale eddies in the coastal ocean. The observations indicate intense mixing, turbulent dissipation, and subsequent restratification. The temperature distribution is closely linked to phytoplankton concentrations suggesting a strong bio-physical coupling. %0 journal article %@ 0094-8276 %A Ohlmann, J.C., Molemaker, M.J., Baschek, B., Holt, B., Marmorino, G., Smith, G. %D 2017 %J Geophysical Research Letters %N 1 %P 330-337 %R doi:10.1002/2016GL071537 %T Drifter observations of submesoscale flow kinematics in the coastal ocean %U https://doi.org/10.1002/2016GL071537 1 %X Fronts and eddies identified with aerial guidance are seeded with drifters to quantify submesoscale flow kinematics. The Lagrangian observations show mean divergence and vorticity values that can exceed 5 times the Coriolis frequency. Values are the largest observed in the field to date and represent an extreme departure from geostrophic dynamics. The study also quantifies errors and biases associated with Lagrangian observations of the underlying velocity strain tensor. The greatest error results from undersampling, even with a large number of drifters. A significant bias comes from inhomogeneous sampling of convergent regions that accumulate drifters within a few hours of deployment. The study demonstrates a Lagrangian sampling paradigm for targeted submesoscale structures over a broad range of scales and presents flow kinematic values associated with vertical velocities O(10) m h−1 that can have profound implications on ocean biogeochemistry. %0 journal article %@ 2169-9275 %A Schultze, L.K.P., Merckelbach, L.M., Carpenter, J.R. %D 2017 %J Journal of Geophysical Research : Oceans %N 11 %P 9092-9109 %R doi:10.1002/2017JC012872 %T Turbulence and Mixing in a Shallow Shelf Sea From Underwater Gliders %U https://doi.org/10.1002/2017JC012872 11 %X The seasonal thermocline in shallow shelf seas acts as a natural barrier for boundary‐generated turbulence, damping scalar transport to the upper regions of the water column and controlling primary production to a certain extent. To better understand turbulence and mixing conditions within the thermocline, two unique 12 and 17 day data sets with continuous measurements of the dissipation rate of turbulent kinetic energy (ɛ) collected by autonomous underwater gliders under stratified to well‐mixed conditions are presented. A highly intermittent ɛ signal was observed in the stratified thermocline region, which was mainly characterized by quiescent flow (turbulent activity index below 7). The rate of diapycnal mixing remained relatively constant for the majority of the time with peaks of higher fluxes that were responsible for much of the increase in bottom mixed layer temperature. The water column stayed predominantly strongly stratified, with a bulk Richardson number across the thermocline well above 2. A positive relationship between the intensity of turbulence, shear, and stratification was found. The trend between turbulence levels and the bulk Richardson number was relatively weak but suggests that ɛ increases as the bulk Richardson number approaches 1. The results also highlight the interpretation difficulties in both quantifying turbulent thermocline fluxes as well as the responsible mechanisms. %0 dataset %@ %A Horstmann, J., Schlick, T., Cysewski, M., Perthun, P., Stell, J., Boedewadt, J., Helzel, T., Seeman, J., Ziemer, F., Gurgel, K., Meywerk, J., Breitbach, G. %D 2017 %J PANGAEA %R doi:10.1594/PANGAEA.876437 %T Sea surface current deduced from Doppler-shift of high-frequency radar backscatter, 2010-10-29 to 2016-12-31 %U https://doi.org/10.1594/PANGAEA.876437 %X The data are organized in daily netCDF files. The first file is from 2010. The measurements are ongoing and will be added in PANGAEA as complete years. All data including the near real-time data will be still available via the COSYNA data portal (doi:10.17616/R3K02T). Details of data management in COSYNA in general are described in an Ocean Science paper (doi:10.5194/os-12-909-2016). %0 journal article %@ 1812-0784 %A Oddo, P., Storto, A., Dobricic, S., Russo, A., Lewis, C., Onken, R., Coelho, E. %D 2016 %J Ocean Science %N 5 %P 1137-1153 %R doi:10.5194/os-12-1137-2016 %T A hybrid variational-ensemble data assimilation scheme with systematic error correction for limited-area ocean models %U https://doi.org/10.5194/os-12-1137-2016 5 %X A hybrid variational-ensemble data assimilation scheme to estimate the vertical and horizontal parts of the background error covariance matrix for an ocean variational data assimilation system is presented and tested in a limited-area ocean model implemented in the western Mediterranean Sea. An extensive data set collected during the Recognized Environmental Picture Experiments conducted in June 2014 by the Centre for Maritime Research and Experimentation has been used for assimilation and validation. The hybrid scheme is used to both correct the systematic error introduced in the system from the external forcing (initialisation, lateral and surface open boundary conditions) and model parameterisation, and improve the representation of small-scale errors in the background error covariance matrix. An ensemble system is run offline for further use in the hybrid scheme, generated through perturbation of assimilated observations. Results of four different experiments have been compared. The reference experiment uses the classical stationary formulation of the background error covariance matrix and has no systematic error correction. The other three experiments account for, or not, systematic error correction and hybrid background error covariance matrix combining the static and the ensemble-derived errors of the day. Results show that the hybrid scheme when used in conjunction with the systematic error correction reduces the mean absolute error of temperature and salinity misfit by 55 and 42 % respectively, versus statistics arising from standard climatological covariances without systematic error correction. %0 conference lecture %@ %A Breitbach, G., Petersen, W., Reinke, S., Gorringe, P., Novellino, A. %D 2016 %J International Conference on Marine Data and Information Systems, IMDIS 2016 %T A common European database for underway data from FerryBoxes %U %X %0 journal article %@ 0006-6729 %A Breitbach, G., Petersen, W., Reinke, S., Gorringe, P., Novellino, A. %D 2016 %J Bollettino di Geofisica Teorica ed Applicata %P 151 %T A common European database for underway data from FerryBoxes %U %X marine data and information. %0 journal article %@ 1094-4087 %A Lefering, I., Roettgers, R., Weeks, R., Connor, D., Utschig, C., Heymann, K., McKee, D. %D 2016 %J Optics express %N 22 %P 24805-24823 %R doi:10.1364/OE.24.024805 %T Improved determination of particulate absorption from combined filter pad and PSICAM measurements %U https://doi.org/10.1364/OE.24.024805 22 %X Filter pad light absorption measurements are subject to two major sources of experimental uncertainty: the so-called pathlength amplification factor, β, and scattering offsets, o, for which previous null-correction approaches are limited by recent observations of non-zero absorption in the near infrared (NIR). A new filter pad absorption correction method is presented here which uses linear regression against point-source integrating cavity absorption meter (PSICAM) absorption data to simultaneously resolve both β and the scattering offset. The PSICAM has previously been shown to provide accurate absorption data, even in highly scattering waters. Comparisons of PSICAM and filter pad particulate absorption data reveal linear relationships that vary on a sample by sample basis. This regression approach provides significantly improved agreement with PSICAM data (3.2% RMS%E) than previously published filter pad absorption corrections. Results show that direct transmittance (T-method) filter pad absorption measurements perform effectively at the same level as more complex geometrical configurations based on integrating cavity measurements (IS-method and QFT-ICAM) because the linear regression correction compensates for the sensitivity to scattering errors in the T-method. This approach produces accurate filter pad particulate absorption data for wavelengths in the blue/UV and in the NIR where sensitivity issues with PSICAM measurements limit performance. The combination of the filter pad absorption and PSICAM is therefore recommended for generating full spectral, best quality particulate absorption data as it enables correction of multiple errors sources across both measurements. %0 journal article %@ 0022-3670 %A Buckley, M.P., Veron, F. %D 2016 %J Journal of Physical Oceanography %N 5 %P 1377-1397 %R doi:10.1175/JPO-D-15-0135.1 %T Structure of the Airflow above Surface Waves %U https://doi.org/10.1175/JPO-D-15-0135.1 5 %X In recent years, much progress has been made to quantify the momentum exchange between the atmosphere and the oceans. The role of surface waves on the airflow dynamics is known to be significant, but our physical understanding remains incomplete. The authors present detailed airflow measurements taken in the laboratory for 17 different wind wave conditions with wave ages [determined by the ratio of the speed of the peak waves Cp to the air friction velocity u* (Cp/u*)] ranging from 1.4 to 66.7. For these experiments, a combined particle image velocimetry (PIV) and laser-induced fluorescence (LIF) technique was developed. Two-dimensional airflow velocity fields were obtained as low as 100 μm above the air–water interface. Temporal and spatial wave field characteristics were also obtained. When the wind stress is too weak to generate surface waves, the mean velocity profile follows the law of the wall. With waves present, turbulent structures are directly observed in the airflow, whereby low-horizontal-velocity air is ejected away from the surface and high-velocity fluid is swept downward. Quadrant analysis shows that such downward turbulent momentum flux events dominate the turbulent boundary layer. Airflow separation is observed above young wind waves (Cp/u*< 3.7), and the resulting spanwise vorticity layers detached from the surface produce intense wave-coherent turbulence. On average, the airflow over young waves (with Cp/u* = 3.7 and 6.5) is sheltered downwind of wave crests, above the height of the critical layer zc [defined by 〈u(zc)〉 = Cp]. Near the surface, the coupling of the airflow with the waves causes a reversed, upwind sheltering effect. %0 journal article %@ 1812-0784 %A Metfies, K., Schroeder, F., Hessel, J., Wollschlaeger, J., Micheller, S., Wolf, C., Kilias, E., Sprong, P., Neuhaus, S., Frickenhaus, S., Petersen, W. %D 2016 %J Ocean Science %N 6 %P 1237-1247 %R doi:10.5194/os-12-1237-2016 %T High-resolution monitoring of marine protists based on an observation strategy integrating automated on-board filtration and molecular analyses %U https://doi.org/10.5194/os-12-1237-2016 6 %X Information on recent biomass distribution and biogeography of photosynthetic marine protists with adequate temporal and spatial resolution is urgently needed to better understand the consequences of environmental change for marine ecosystems. Here we introduce and review a molecular-based observation strategy for high-resolution assessment of these protists in space and time. It is the result of extensive technology developments, adaptations and evaluations which are documented in a number of different publications, and the results of the recently completed field testing which are introduced in this paper. The observation strategy is organized at four different levels. At level 1, samples are collected at high spatiotemporal resolution using the remotely controlled automated filtration system AUTOFIM. Resulting samples can either be preserved for later laboratory analyses, or directly subjected to molecular surveillance of key species aboard the ship via an automated biosensor system or quantitative polymerase chain reaction (level 2). Preserved samples are analyzed at the next observational levels in the laboratory (levels 3 and 4). At level 3 this involves molecular fingerprinting methods for a quick and reliable overview of differences in protist community composition. Finally, selected samples can be used to generate a detailed analysis of taxonomic protist composition via the latest next generation sequencing technology (NGS) at level 4. An overall integrated dataset of the results based on the different analyses provides comprehensive information on the diversity and biogeography of protists, including all related size classes. At the same time the cost of the observation is optimized with respect to analysis effort and time. %0 journal article %@ 1726-4170 %A Merckelbach, L. %D 2016 %J Biogeosciences %N 24 %P 6637-6649 %R doi:10.5194/bg-13-6637-2016 %T Depth-averaged instantaneous currents in a tidally dominated shelf sea from glider observations %U https://doi.org/10.5194/bg-13-6637-2016 24 %X In the near-real-time mode the algorithm provides estimates of the currents that the glider is expected to encounter during its next few dives. Combined with a behavioural and dynamic model of the glider, this yields predicted trajectories, the information of which is incorporated in warning messages issued to ships by the (German) authorities. In delayed mode the algorithm produces useful estimates of the depth-averaged currents, which can be used in (process-based) analyses in case no other source of measured current information is available. %0 journal article %@ 1354-1013 %A Reid, P.C., Hari, R.E., Beaugrand, G., Livingstone, D.M., Marty, C., Straile, D., Barichivich, J., Goberville, E., Adrian, R., Aono, Y., Brown, R., Foster, J., Groisman, P., Helaouet, P., Hsu, H.-H., Kirby, R., Knight, J., Kraberg, A., Li, J., Lo, T.-T., Myneni, R.B., North, R.P., Pounds, J.A., Sparks, T., Stuebi, R., Tian, Y., Wiltshire, K.H., Xiao, D., Zhu, Z. %D 2016 %J Global Change Biology %N 2 %P 682-703 %R doi:10.1111/gcb.13106 %T Global impacts of the 1980s regime shift %U https://doi.org/10.1111/gcb.13106 2 %X Despite evidence from a number of Earth systems that abrupt temporal changes known as regime shifts are important, their nature, scale and mechanisms remain poorly documented and understood. Applying principal component analysis, change-point analysis and a sequential t-test analysis of regime shifts to 72 time series, we confirm that the 1980s regime shift represented a major change in the Earth's biophysical systems from the upper atmosphere to the depths of the ocean and from the Arctic to the Antarctic, and occurred at slightly different times around the world. Using historical climate model simulations from the Coupled Model Intercomparison Project Phase 5 (CMIP5) and statistical modelling of historical temperatures, we then demonstrate that this event was triggered by rapid global warming from anthropogenic plus natural forcing, the latter associated with the recovery from the El Chichón volcanic eruption. The shift in temperature that occurred at this time is hypothesized as the main forcing for a cascade of abrupt environmental changes. Within the context of the last century or more, the 1980s event was unique in terms of its global scope and scale; our observed consequences imply that if unavoidable natural events such as major volcanic eruptions interact with anthropogenic warming unforeseen multiplier effects may occur. %0 journal article %@ 0948-4280 %A Druecker, S., Steglich, D., Merckelbach, L., Werner, A., Bargmann, S. %D 2016 %J Journal of Marine Science and Technology %N 2 %P 261-270 %R doi:10.1007/s00773-015-0349-7 %T Finite element damage analysis of an underwater glider–ship collision %U https://doi.org/10.1007/s00773-015-0349-7 2 %X Underwater gliders, which are profiling autonomous underwater vehicles designed to make oceanographic measurements, are increasingly used in the coastal ocean. As they regularly surface for data transmission, gliders increasingly pose a risk for fast ships. In order to estimate the extent of damage due to collision, 3D finite element simulations of collisions between a glider and a high-speed craft with a glass-fiber reinforced plastic hull are performed. Different collision scenarios such as impact locations, angles of attack and speeds are examined. The results are compared to an analytical solution based on simplifying assumptions. Although both methods reveal consistent results, it is shown that finite element simulations are required to account for the 3D shape of the ship. The results indicate that at ship velocities exceeding 7.5 m/s (14.6 kt) the glider penetrates the ship’s hull causing severe damage to its structure. %0 conference lecture %@ %A Druecker, S., Steglich, D., Merckelbach, L., Werner, A., Bargmann, S. %D 2016 %J GAMM Jahrestagung 2016 %T Finite element and simplified analytical calculation of an underwater glider-ship collision %U %X %0 journal article %@ 1932-6203 %A Carpenter, J.R., Merckelbach, L., Callies, U., Clark, S., Gaslikova, L., Baschek, B. %D 2016 %J PLoS One %N 8 %P 0160830 %R doi:10.1371/journal.pone.0160830 %T Potential Impacts of Offshore Wind Farms on North Sea Stratification %U https://doi.org/10.1371/journal.pone.0160830 8 %X Advances in offshore wind farm (OWF) technology have recently led to their construction in coastal waters that are deep enough to be seasonally stratified. As tidal currents move past the OWF foundation structures they generate a turbulent wake that will contribute to a mixing of the stratified water column. In this study we show that the mixing generated in this way may have a significant impact on the large-scale stratification of the German Bight region of the North Sea. This region is chosen as the focus of this study since the planning of OWFs is particularly widespread. Using a combination of idealised modelling and in situ measurements, we provide order-of-magnitude estimates of two important time scales that are key to understanding the impacts of OWFs: (i) a mixing time scale, describing how long a complete mixing of the stratification takes, and (ii) an advective time scale, quantifying for how long a water parcel is expected to undergo enhanced wind farm mixing. The results are especially sensitive to both the drag coefficient and type of foundation structure, as well as the evolution of the pycnocline under enhanced mixing conditions—both of which are not well known. With these limitations in mind, the results show that OWFs could impact the large-scale stratification, but only when they occupy extensive shelf regions. They are expected to have very little impact on large-scale stratification at the current capacity in the North Sea, but the impact could be significant in future large-scale development scenarios. %0 conference lecture (invited) %@ %A Quante, M., Colijn, F., Noehren, I. %D 2016 %J 1st Baltic Earth Conference %T The North Sea Region Climate Change Assessment (NOSCCA): What happens in the south west of BACC? %U %X %0 journal article %@ 0272-7714 %A North, R.P., Riethmueller, R., Baschek, B. %D 2016 %J Estuarine, Coastal and Shelf Science %P 221-229 %R doi:10.1016/j.ecss.2016.06.031 %T Detecting small–scale horizontal gradients in the upper ocean using wavelet analysis %U https://doi.org/10.1016/j.ecss.2016.06.031 %X Mesoscale and submesoscale eddies and fronts in the upper ocean are often closely coupled with biogeochemical processes. Improved instrumentation provides high–resolution data in both the horizontal and vertical capturing this large range of scales (1–100 km), but novel analysis methods are still needed to take full advantage of this advancement. A new method using wavelet analysis is therefore proposed to identify the horizontal scales at which biophysical interactions occur, defined by concurrent fluctuations in temperature and phytoplankton patchiness. The method is applied to temperature and chlorophyll–a fluorescence data measured in the North Sea’s German Bight during early spring using a towed undulating vehicle. The wavelet analysis identified the scale and location of individual features characterized by horizontal gradients of temperature and chlorophyll–a fluorescence. Applied to multiple transects, the method can also retrieve the statistics of relevant biophysical scales in a particular region. The combined analysis of seven transects suggests that physical and biogeochemical tracers tend to align at scales of 3–15 km in the German Bight, highlighting the likely relevance of submesoscale processes in this region. In general, the proposed wavelet analysis method is shown to be a robust tool for the analysis of biophysical interactions across a range of scales. %0 book part %@ %A Baschek, B., Gade, M., Bernem, K.-H.van, Schwichtenberg, F. %D 2016 %J The Handbook of Environmental Chemistry %P 161-192 %R doi:10.1007/698_2015_399 %T The German Operational Monitoring System in the North Sea: Sensors, Methods and Example Data %U https://doi.org/10.1007/698_2015_399 %X Operational oil pollution surveillance has been performed in Germany for almost 30 years. Sophisticated state-of-the-art sensors are being used for frequent airborne surveillance, while satellite data are used as prewarning and additional information input on a routine basis. In parallel, basic research on the imaging of marine oil pollution by synthetic aperture radar (SAR) has been performed, and a basic understanding of the imaging of biogenic and anthropogenic marine surface films by active microwave sensors has been developed. In this paper, we provide an overview of the current operational surveillance system, and we give some historical background summarising some of the results of the research conducted during the past decades. Within this chapter, example images from pollution events are given for several sensors. The German coast’s spatial and temporal vulnerability to oil pollution is quantified, and the use of dispersants in a highly vulnerable ecosystem such as the “Wadden Sea” is discussed. %0 journal article %@ 2045-2322 %A Borges, L.M.S., Hollatz, C., Lobo, J., Cunha, A.M., Vilela, A.P., Calado, G., Coelho, R., Costa, A.C., Ferreira, M.S.G., Costa, M.H., Costa, F.O. %D 2016 %J Scientific Reports %P 20226 %R doi:10.1038/srep20226 %T With a little help from DNA barcoding: Investigating the diversity of Gastropoda from the Portuguese coast %U https://doi.org/10.1038/srep20226 %X The Gastropoda is one of the best studied classes of marine invertebrates. Yet, most species have been delimited based on morphology only. The application of DNA barcodes has shown to be greatly useful to help delimiting species. Therefore, sequences of the cytochrome c oxidase I gene from 108 specimens of 34 morpho-species were used to investigate the molecular diversity within the gastropods from the Portuguese coast. To the above dataset, we added available COI-5P sequences of taxonomically close species, in a total of 58 morpho-species examined. There was a good match between ours and sequences from independent studies, in public repositories. We found 32 concordant (91.4%) out of the 35 Barcode Index Numbers (BINs) generated from our sequences. The application of a ranking system to the barcodes yield over 70% with top taxonomic congruence, while 14.2% of the species barcodes had insufficient data. In the majority of the cases, there was a good concordance between morphological identification and DNA barcodes. Nonetheless, the discordance between morphological and molecular data is a reminder that even the comparatively well-known European marine gastropods can benefit from being probed using the DNA barcode approach. Discordant cases should be reviewed with more integrative studies. %0 journal article %@ 0022-0981 %A Weigelt, R., Lippert, H., Borges, L.M.S., Appelqvist, C., Karsten, U., Bastorp, R. %D 2016 %J Journal of Experimental Marine Biology and Ecology %P 154-162 %R doi:10.1016/j.jembe.2015.11.008 %T First time DNA barcoding of the common shipworm Teredo navalis Linnaeus 1758 (Mollusca: Bivalvia: Teredinidae): Molecular-taxonomic investigation and identification of a widespread wood-borer %U https://doi.org/10.1016/j.jembe.2015.11.008 %X Classification of T. navalis into the system of wood-boring bivalves using a combined 18S/28S dataset showed no differentiation between specimens from Europe and the North American East Coast. The results of the COI dataset analyses showed high haplotype diversity in combination with a low nucleotide diversity and a star-shaped network with a predominant haplotype occurring in all investigated regions. Moreover, no indications have been found on a sibling species in the Baltic Sea. The data indicate a recent population expansion for the examined sampling sites whereas the origin of the assumed worldwide distributed species T. navalis remains open. %0 journal article %@ 0143-1161 %A Karimova, S., Gade, M. %D 2016 %J International Journal of Remote Sensing %N 10 %P 2394-2414 %R doi:10.1080/01431161.2016.1145367 %T Improved statistics of sub-mesoscale eddies in the Baltic Sea retrieved from SAR imagery %U https://doi.org/10.1080/01431161.2016.1145367 10 %X In the present article the spatio-temporal distribution of sub-mesoscale eddies seen in Envisat Advanced Synthetic Aperture Radar (ASAR) imagery of the Baltic Sea is discussed. A total of 1250 ASAR images acquired between 2009 and 2011 form the basis of our studies and show imprints of almost 7000 sub-mesoscale eddies. Since the visibility of vortical structures in synthetic aperture radar (SAR) imagery significantly depends on the near-surface wind speed, wind data from a numerical model of the Baltic Sea were additionally used to obtain improved eddy statistics. Seasonally averaged fields of near-surface wind speed, surface currents, sea surface temperature (SST), and SST gradient were also analysed in order to reveal the role of these hydrophysical parameters in the observed spatial and temporal variation of sub-mesoscale eddies. %0 journal article %@ 1094-4087 %A Hieronymi, M. %D 2016 %J Optics express %N 14 %P A1045-A1068 %R doi:10.1364/OE.24.0A1045 %T Polarized reflectance and transmittance distribution functions of the ocean surface %U https://doi.org/10.1364/OE.24.0A1045 14 %X Two aspects of ocean modelling are treated: representation of ocean waves considering all size-classes of waves and tracing of light-interactions at the wavy sea surface. Nonlinear wave profiles are realized accounting for a wide range of climatologically relevant sea states and wind speeds. Polarized ray tracing is used to investigate air-incident and whitecap-free reflectance and transmittance distributions with high angular resolution subject to sea-characterizing parameters, such as significant wave height, peak wave period, wind speed, and surface roughness. Wave-shadowing effects of incident and multiple reflected rays are fully considered. Their influence mostly starts with incidence angles greater than 60°, i.e., when the sun is near the horizon, and is especially pronounced for steep sea states. The net effect of multiple reflections is a redistribution of reflectance and transmittance fractions in their respective hemispheres and a slight increase of the net transmission of light into the sea. Revised reflectance and transmittance distribution functions, RDF and TDF, are provided depending on surface roughness in terms of the mean-square slope; reference is made to other sea state parameters. In comparison with the slope statistics approach, uncertainties related to sun near the horizon are reduced and on average this study yields somewhat higher reflectance values with some variability related to the sea state. By means of provided data, irradiance and radiance reflectances can be computed using desired sky radiance distributions, e.g., clear sky, overcast or partly cloudy sky, as well as wind or sea state information including wave propagation direction. %0 journal article %@ 0364-9059 %A Wollschlaeger, J., Voss, D., Zielinski, O., Petersen, W. %D 2016 %J IEEE Journal of Oceanic Engineering %N 4 %P 753-762 %R doi:10.1109/JOE.2016.2557466 %T In Situ Observations of Biological and Environmental Parameters by Means of Optics - Development of Next-Generation Ocean Sensors With Special Focus on an Integrating Cavity Approach %U https://doi.org/10.1109/JOE.2016.2557466 4 %X To meet the requirements of increasing environmental awareness in aquatic ecosystems, optical techniques offer a fast and reliable opportunity for a wide range of applications providing high-resolution measurements. In this respect, important parameters which have to be addressed include phytoplankton biomass and taxonomic composition, total suspended matter, dissolved organic matter, as well as hazardous substances, e.g., polycyclic aromatic hydrocarbons (PAHs). Requiring comparable low effort, optical methods are a convenient and noninvasive way to derive information on the optical active substances in different water bodies. Various approaches and devices are available, either aiming on the determination of the water's inherent optical properties or on measuring the fluorescence properties of different constituents. This contribution presents the objectives and measurement principles of two new optical sensor developments in this respect. A special focus lies on an integrating cavity approach for hyperspectral absorption measurement. This approach overcomes two common problems in classical absorption measurement of seawater: 1) usually low concentration of absorbing material in the water negatively affecting accurate measurements of untreated samples; and 2) errors introduced by light scattering of particles requiring empirical corrections to obtain good accuracy. To combine these advantages with the possibilities of automated, long-term high-frequency measurements, an integrating cavity was adapted for flow-through operation. First field results obtained by the resulting Hyperspectral Absorption Sensor (HyAbS) in the North Sea and off the Norwegian coast are evaluated and compared with discrete measurements. The second development is a matrix-fluorescence sensor with flexible wavelength configuration for the detection and characterization of dissolved substances, such as fluorescent dissolved organic matter (FDOM) and PAHs. Here, the measurement principl- of the sensor and first field results from a related, laboratory-based method will be presented as a preliminary work necessary for the development of the final in situ sensor. Furthermore, future plans for both instruments as well as a possible combination will be discussed. In summary, both approaches have the potential to be multiparameter instruments for high-resolution measurements of environmental parameters. %0 journal article %@ 0196-2892 %A Huang, W., Carrasco, R., Shen, C., Gill, E.W., Horstmann, J. %D 2016 %J IEEE Transactions on Geoscience and Remote Sensing %N 5 %P 2988-2997 %R doi:10.1109/TGRS.2015.2509781 %T Surface Current Measurements Using X-Band Marine Radar With Vertical Polarization %U https://doi.org/10.1109/TGRS.2015.2509781 5 %X In this paper, the retrieval of sea surface current velocity from vertically polarized (V-pol) X-band marine radar data is presented. Three different methods, including the iterative least square approach, the normalized scalar product method, and the polar current shell algorithm, that have been used for horizontally polarized data are employed here. A comprehensive comparison of the performance of the three methods is conducted using the radar images collected by the V-pol radar deployed on the Forschungsplattformen in Nord- und Ostsee No. 3 (FINO3) offshore research platform and the acoustic Doppler current profiler (ADCP) data in the North Sea. The results indicate that all three methods are capable of providing reliable current speed and direction measurements from V-pol data, with similar performance. Based on the experimental data for which the current magnitude is less than 0.5 m/s, the radar-derived results agree best with the ADCP data at a depth of 6–8 m, with the root mean square difference for current velocity x - and y -components being 7.2–8.9 cm/s. The correlation coefficients between the radar-derived and ADCP-measured current velocity components are as high as 0.87–0.93. %0 journal article %@ 1094-4087 %A Harmel, T., Hieronymi, M., Slade, W., Roettgers, R., Roullier, F., Chami, M. %D 2016 %J Optics express %N 2 %P A 234-A 256 %R doi:10.1364/OE.24.00A234 %T Laboratory experiments for inter-comparison of three volume scattering meters to measure angular scattering properties of hydrosols %U https://doi.org/10.1364/OE.24.00A234 2 %X Measurements of the volume scattering function (VSF) of hydrosols is of primary importance to investigate the interaction of light with hydrosols and to further interpret in situ and remote sensing data of ocean color. In this paper, a laboratory inter-comparison experiment of three recently developed VSF meters that are able to measure the scattered light for a wide range of scattering angle at 515 nm wavelength is performed using phytoplankton cultures and mineral-like hydrosols. A rigorous measurement protocol was employed to ensure good quality data. In particular, the protocol enabled removing the influence of bacteria on the hydrosols within the sample. The differences in the VSF measurements between the instruments vary from 10 to 25% depending on the composition of the hydrosols. The analysis of the angular features of the VSF revealed a sharp increase of the VSF beyond the scattering angle of 150° for some phytoplankton species. Such behavior is observed for two of the three VSF meters, thus suggesting that it is not due to instrumental artifacts but more likely to phytoplankton optical properties themselves. Moreover, comparisons with currently used theoretical phase functions show that the models are not able to reproduce satisfactorily the directional patterns in the backscattering region. This study suggests that a better modelling of the VSF shape of phytoplankton at high scattering angles is required to correctly represent the angular shape of the VSF in the backscattering hemisphere. Tabulated values of the measured phase functions are provided for scattering angles from 0.1 to 175°. %0 conference lecture %@ %A Hieronymi, M., Krasemann, H., Mueller, D., Brockmann, C., Ruescas, A., Stelzer, K., Nechad, B., Ruddick, K., Simis, S., Tilstone, G., Steinmetz, F., Regner, P. %D 2016 %J Living Planet Symposium 2016 %T Ocean Colour Remote Sensing of Extreme Case-2 Waters %U %X %0 journal article %@ 0022-3670 %A Hieronymus, M., Carpenter, J.R. %D 2016 %J Journal of Physical Oceanography %N 8 %P 2553-2569 %R doi:10.1175/JPO-D-15-0155.1 %T Energy and Variance Budgets of a Diffusive Staircase with Implications for Heat Flux Scaling %U https://doi.org/10.1175/JPO-D-15-0155.1 8 %X The steady-state energy and thermal variance budgets form the basis for most current methods for evaluating turbulent fluxes of buoyancy, heat, and salinity. This study derives these budgets for a double-diffusive staircase and quantifies them using direct numerical simulations; 10 runs with different Rayleigh numbers are considered. The energy budget is found to be well approximated by a simple three-term balance, while the thermal variance budget consists of only two terms. The two budgets are also combined to give an expression for the ratio of the heat and salt fluxes. The heat flux scaling is also studied and found to agree well with earlier estimates based on laboratory experiments and numerical simulations at high Rayleigh numbers. At low Rayleigh numbers, however, the authors find large deviations from earlier scaling laws. Last, the scaling theory of Grossman and Lohse, which was developed for Rayleigh–Bénard convection and is based on the partitioning of the kinetic energy and tracer variance dissipation, is adapted to the diffusive regime of double-diffusive convection. The predicted heat flux scalings are compared to the results from the numerical simulations and earlier estimates. %0 conference paper %@ %A Hieronymi, M., Krasemann, H., Mueller, D., Brockmann, C., Ruescas, A., Stelzer, K., Nechad, B., Ruddick, K., Simis, S., Tilstone, G., Steinmetz, F., Regner, P. %D 2016 %J Proceedings of ESA Living Planet Symposium 2016 %P Sco 3-1 %T Ocean Colour Remote Sensing of Extreme Case-2 Waters %U %X Many coastal seas and inland waters have water properties which are outside the normal conditions used for ocean colour algorithm design. In the ESA-funded “Case-2 Extreme” project, retrieval methods for OC products in extreme Case-2 waters are developed, tested, implemented, and validated primarily with reference to the capabilities of the Sentinel-3 OLCI and SLSTR instruments but also tested for Sentinel 2 where applicable. Based on hyperspectral radiative transfer simulation, in situ, and Earth observation data, specific features of extreme scattering and absorbing waters are reviewed. A reflectance-based sub-classification scheme of Case-2 waters for various levels of turbidity is introduced. Opportunities of using new wavebands are highlighted. %0 conference poster %@ %A Hieronymi, M. %D 2016 %J Living Planet Symposium 2016 %T Reflectance and transmittance properties of sea surfaces – Aspects of polarized ray tracing %U %X %0 conference paper %@ %A Hieronymi, M. %D 2016 %J Proceedings of ESA Living Planet Symposium 2016 %P Pocea 108 %T Reflectance and transmittance properties of sea surfaces – Aspects of polarized ray tracing %U %X The present paper highlights some aspects of reflectance and transmittance properties of the ocean and addresses the question whether differences occur with initially polarized vs. unpolarized ray tracing. Furthermore, aspects of single vs. multiple scattering at different sea state surfaces are discussed. %0 conference paper %@ %A Quante, M., Colijn, F., Noehren, I. %D 2016 %J International Baltic Earth Secretariat Publication, Conference Proceedings, 1st Baltic Earth Conference %P 180-181 %T The North Sea Region Climate Change Assessment (NOSCCA): What happens in the south west of BACC? %U %X %0 journal article %@ 2169-9275 %A Becherer, J., Floeser, G., Umlauf, L., Burchard, H. %D 2016 %J Journal of Geophysical Research : Oceans %N 8 %P 6251-6270 %R doi:10.1002/2016JC011640 %T Estuarine Circulation vs Tidal Pumping: Sediment Transport in a Well-Mixed Tidal Inlet %U https://doi.org/10.1002/2016JC011640 8 %X High-resolution water column observations have been carried out in the Wadden Sea to understand suspended particulate mater (SPM) transport in well-mixed tidal channels . These observations include more than 4000 consecutive CTD-, micro-structure shear and turbidity profiles from a free-falling micro-structure probe, as well as velocity data from an ADCP and SPM samples for calibration. A horizontal density gradient was established by a landward temperature gradient built up during an extraordinarily warm and calm spring season. Tidal averaging along σ-layers (relative depth) provides the first direct observations of along-channel estuarine circulation in the Wadden Sea, with net inflow near the bottom and outflow near the surface. Increased westerly (up-estuary) winds during the second part of the campaign weakened and eventually even reversed estuarine circulation and yielded a net barotropic eastward transport. SPM concentrations showed a strong quarter-diurnal signal with maxima near full flood and full ebb and were generally lower during the calm period and increased during the windy period, mainly due to wave-related resuspension over nearby inter-tidal flats. The sediment flux analysis was based on a decomposition of the vertically integrated SPM flux into a barotropic advective component, an estuarine circulation component and a tidal pumping component. As a result, tidal pumping (due to ebb-dominance weakly seaward) dominated the SPM flux during calm conditions, whereas barotropic advection dominated the strong landward SPM flux during the windy period. Along-channel estuarine circulation is found to be of minor importance for the net SPM-transport in such well-mixed systems. This article is protected by copyright. All rights reserved. %0 journal article %@ 1812-0784 %A Breitbach, G., Krasemann, H., Behr, D., Beringer, S., Lange, U., Vo, N., Schroeder, F. %D 2016 %J Ocean Science %N 4 %P 909-923 %R doi:10.5194/os-12-909-2016 %T Accessing Diverse Data Comprehensively – CODM the COSYNA Data Portal %U https://doi.org/10.5194/os-12-909-2016 4 %X The coastal observation system COSYNA aims to describe the physical and biogeochemical state of a regional coastal system. The COSYNA data management is the link between observations, model results and data usage. The challenge for the COSYNA data management CODM1 COSYNA Data and Metadata, http://codm.hzg.de/codm or doi:10.17616/R3K02T is the integration of diverse data sources in terms of parameters, dimensionality and observation methods to gain a comprehensive view of the observations. This is achieved by describing the data using metadata in a generic way and by making all gathered data available for different analyses and visualisations in an interrelated way, independent of data dimensionality. Different parameter names for the same observed property are mapped to the corresponding CF2 climate and forecast standard name leading to standardised and comparable metadata. These metadata together with standardised web services are the base for the data portal. The URLs of these web services are also stored within the metadata as direct data access URLs, e.g. a map such as a GetMap request. %0 conference lecture %@ %A Hieronymi, M. %D 2016 %J International Radiation Symposium, IRS 2016 %T Reflectance and transmittance properties of sea surfaces as function of sea state and wind speed %U %X %0 report %@ 0283-7714 %A Kuznetsov, I., Eilola, K., Dieterich, C., Hordoir, R., Axell, L., Hoeglund, A., Schimanke, S. %D 2016 %J %T Model study on the variability of ecosystem parameters in the Skagerrak-Kattegat area, effect of load reduction in the North Sea and possible effect of BSAP on Skagerrak-Kattegat area : Technical Report - SMHI %U %X Newly developed ecosystem model NEMO-Nordic-SCOBI was applied to Skagerrak - Kattegat area to investigate the variability of some indicators of the ecosystem. Also, two sensitivity runs were performed to investigate possible effect of the Baltic Sea Action Plan (BSAP) and a river loads reduction scenario on the Skagerrak - Kattegat area. The performed investigation could be used “to provide a basis to assist with the interpretation of measurement data before the Intermediate Assessments Eutrophication status assessment”. Comparison of simulation results with observations indicates acceptable model performance. Modeled sea surface salinity, temperature and dissolved inorganic phosphate (DIP) are in good agreement with observations. At the same time, the model has a bias in certain areas of the investigated region for dissolved inorganic nitrogen (DIN) and dissolved silicate during the winter season. However, the model in its current state shows good enough results for the performed investigation. Results of the two sensitivity studies show a decrease of sea surface nutrients concentrations during winter period in both regions. In the Skagerrak area the decrease is due to reduction in river nutrient loads in North Sea. In the Kattegat area there is a decrease of dissolved phosphate due to the implementation of BSAP. At the same time, in both scenarios, no significant changes were obtained for near bottom oxygen or surface layer Chl-a. %0 journal article %@ 0718-221X %A Sivrikaya, H., Cetin, H., Tuemen, I., Temiz, C., Borges, L.M.S. %D 2016 %J Maderas: Ciencia y Technologia %N 2 %P 349-360 %R doi:10.4067/S0718-221X2016005000032 %T Performance of copper azole treated softwoods exposed to marine borers %U https://doi.org/10.4067/S0718-221X2016005000032 2 %X All untreated test panels scored an average of 4 (heavily attacked) after a 14 month period. The cellulose ratio of Black pine decreased from 56 % to 50 %, and the holo-cellulose ratio from 76 % to 71 %. The treated samples showed resistance against marine borers although the copper (cu) leaching was high during the 14 months exposure underwater. %0 journal article %@ 1812-0784 %A Pitarch, J., Volpe, G., Colella, S., Krasemann, H., Santoleri, R. %D 2016 %J Ocean Science %N 2 %P 379-389 %R doi:10.5194/os-12-379-2016 %T Remote sensing of chlorophyll in the Baltic Sea at basin scale from 1997 to 2012 using merged multi-sensor data %U https://doi.org/10.5194/os-12-379-2016 2 %X A 15-year (1997–2012) time series of chlorophyll a (Chl a) in the Baltic Sea, based on merged multi-sensor satellite data was analysed. Several available Chl a algorithms were sea-truthed against the largest in situ publicly available Chl a data set ever used for calibration and validation over the Baltic region. To account for the known biogeochemical heterogeneity of the Baltic, matchups were calculated for three separate areas: (1) the Skagerrak and Kattegat, (2) the central Baltic, including the Baltic Proper and the gulfs of Riga and Finland, and (3) the Gulf of Bothnia. Similarly, within the operational context of the Copernicus Marine Environment Monitoring Service (CMEMS) the three areas were also considered as a whole in the analysis. In general, statistics showed low linearity. However, a bootstrapping-like assessment did provide the means for removing the bias from the satellite observations, which were then used to compute basin average time series. Resulting climatologies confirmed that the three regions display completely different Chl a seasonal dynamics. The Gulf of Bothnia displays a single Chl a peak during spring, whereas in the Skagerrak and Kattegat the dynamics are less regular and composed of highs and lows during winter, progressing towards a small bloom in spring and a minimum in summer. In the central Baltic, Chl a follows a dynamics of a mild spring bloom followed by a much stronger bloom in summer. Surface temperature data are able to explain a variable fraction of the intensity of the summer bloom in the central Baltic. %0 dataset %@ %A Riethmüller, R. %D 2016 %J PANGAEA %R doi:10.1594/PANGAEA.863414 %T Continuous thermosalinograph oceanography along HEINCKE cruise track HE445 %U https://doi.org/10.1594/PANGAEA.863414 %X %0 journal article %@ 0924-7963 %A Brumovsky, M., Becanova, J., Kohoutek, J., Thomas, H., Petersen, W., Soerensen, K., Sanka, O., Nizzetto, L. %D 2016 %J Journal of Marine Systems %P 47-56 %R doi:10.1016/j.jmarsys.2016.03.004 %T Exploring the occurrence and distribution of contaminants of emerging concern through unmanned sampling from ships of opportunity in the North Sea %U https://doi.org/10.1016/j.jmarsys.2016.03.004 %X Chemical pollution is of concern for the marine environment. New European regulation demands exposure and impact assessment to be conducted in coastal environments in order to define and ensure fulfillment of environmental quality standards. A cost-effective approach for monitoring the over 100,000 km of European coasts is necessary. This proof-of-concept study focuses on the use of unmanned water sampling from a commercial ship of opportunity to implement monitoring of marine contaminants of emerging concern. Marine areas that are not directly affected by river plumes or other direct sources were covered in order to provide information on background pollution. 14 currently used pesticides, 11 pharmaceuticals and personal care products and 3 food additives were detected in water samples through targeted analysis at sub-ng to tenths of ng/L levels in both coastal and offshore areas of the North Sea. Among contaminants, 6 pesticides (dimethoate, fenpropimorph, pendimethalin, propiconazole, tebuconazole and temephos), 3 pharmaceuticals (acetaminophen, naproxen and ketoprofen) and 2 food additives (acesulfame and saccharine) have never been detected before in offshore areas. 4 pesticides (diuron, isoproturon, metazachlor and terbuthylazine), 4 pharmaceuticals (carbamazepine, atenolol, ibuprofen and ketoprofen) and 2 food additives (sucralose and acesulfame) were detected in over 90% of the samples. The antibiotic sulfamethoxazole was detected in 50% of the samples at tenths of pg/L levels, including some offshore areas. Our study highlights that the use of ships of opportunity can provide a key support for the development and cost-effective implementation of marine monitoring of chemical pollutants in Europe and elsewhere. %0 conference paper %@ %A Mueller, D., Krasemann, H., Zuehlke, M., Doerffer, R., Brockmann, C., Steinmetz, F., Valente, A., Brotas, V., Grant, M.G., Sathyendranath, S., Melin, F., Franz, B.A., Mazeran, C., Regner, P. %D 2016 %J Proceedings of ESA Living Planet Symposium 2016 %P Pmeth 102 %T The Assessment of Atmospheric Correction Processors for MERIS Based on In-Situ Measurements - Updates in OC-CCI Round Robin %U %X The Ocean Colour Climate Change Initiative (OCCCI)providesalong-termtimeseriesofoceancolour data and investigates the detectable climate impact. A reliable and stable atmospheric correction (AC) procedure is the basis for ocean colour products of the necessary high quality. The selection of atmospheric correction processors is repeated regularly based on a round robin exercise, at the latest when a revised production and release of the OC-CCI merged product is scheduled. Most of the AC processors are under constant development and changes are implemented to improve the quality of satellite-derived retrievals of remote sensing reflectances. The changes between versions of the inter-comparison are not restricted to the implementation of AC processors. There are activities to improve the quality flagging for some processors, and the system vicarious calibration for AC algorithms in their sensor specific behaviour are widely studied. Each inter-comparison starts with an updated in-situ database, as more spectra are included inordertobroadenthetemporalandspatialrangeof satellite match-ups. While the OC-CCI’s focus has laid on case-1 waters in the past, it has expanded to the retrieval of case-2 products now. In light of this goal, new bidirectional correction procedures (normalisation) for the remote sensing spectra have been introduced. As in-situ measurements are not always available at the satellite sensor specific central wavelengths, a band-shift algorithm has to be applied to the dataset. %0 conference poster %@ %A Mueller, D., Krasemann, H., Zuehlke, M., Doerffer, R., Brockmann, C., Steinmetz, F., Valente, A., Brotas, V., Grant, M.G., Sathyendranath, S., Melin, F., Franz, B.A., Mazeran, C., Regner, P. %D 2016 %J Living Planet Symposium 2016 %T The Assessment of Atmospheric Correction Processors for MERIS Based on In-Situ Measurements - Updates in OC-CCI Round Robin %U %X %0 journal article %@ 1755-876X %A Sparnocchia, S., Nair, R., Petihakis, G., Aydogdu, A., Dobricic, S., Farcy, P., Martinelli, M., Petersen, W., de la Villeon, L.P. %D 2016 %J Journal of Operational Oceanography %N S1 %P S 193-S 201 %R doi:10.1080/1755876X.2015.1114808 %T An interlinked coastal observatory network for Europe %U https://doi.org/10.1080/1755876X.2015.1114808 S1 %X Existing coastal observatories in European waters are complex systems consisting of different observational components, providing crucial operational data for assessment, model validation and assimilation purposes. However, the geographical, structural, functional and operational heterogeneities that characterise them pose an enormous challenge to their efficient exploitation as information providers on a broader, cross-border, regional scale. To address this problem, the European Union (EU) Seventh Framework Programme (FP7) Towards a Joint European Research Infrastructure Network for Coastal Observatories (JERICO) project is creating a shared, pan-European framework for the networking of such observatories, promoting the identification and dissemination of best practices for their design, implementation and maintenance, as well as common data distribution and transnational access protocols to enhance their performance and sustainability. In doing so, the project is also laying down the foundation for the coastal element of the nascent European Ocean Observing System. %0 editorial %@ 1687-725X %A Serafino, F., Horstmann, J., Nieto Borge, J.C., Lugni, C., Brocchini, M. %D 2016 %J Journal of Sensors %P 1720563 %R doi:10.1155/2016/1720563 %T Editorial: Sensors for Coastal Monitoring %U https://doi.org/10.1155/2016/1720563 %X No abstract %0 journal article %@ 1755-098X %A Lobo, J., Teixeira, M.A.L., Borges, L.M.S., Ferreira, M.S.G., Hollatz, C., Gomes, P.A., Sousa, R., Ravara, A., Costa, M.H., Costa, F.O. %D 2016 %J Molecular Ecology Resources %N 1 %P 298-313 %R doi:10.1111/1755-0998.12441 %T Starting a DNA barcode reference library for shallow water polychaetes from the southern European Atlantic coast %U https://doi.org/10.1111/1755-0998.12441 1 %X Annelid polychaetes have been seldom the focus of dedicated DNA barcoding studies, despite their ecological relevance and often dominance, particularly in soft-bottom estuarine and coastal marine ecosystems. Here we report the first assessment of the performance of DNA barcodes in the discrimination of shallow water polychaete species from the southern European Atlantic coast, focusing on specimens collected in estuaries and coastal ecosystems of Portugal. We analysed cytochrome oxidase I DNA barcodes (COI-5P) from 164 specimens, which were assigned to 51 morphospecies. To our dataset from Portugal, we added available published sequences selected from the same species, genus or family, to inspect for taxonomic congruence among studies and collection location. The final dataset comprised 290 specimens and 79 morphospecies, which generated 99 Barcode index numbers (BINs) within Barcode of Life Data Systems (BOLD). Among these, 22 BINs were singletons, 47 other BINs were concordant, confirming the initial identification based on morphological characters, and 30 were discordant, most of which consisted on multiple BINs found for the same morphospecies. Some of the most prominent cases in the latter category include Hediste diversicolor (O.F. Müller, 1776) (7), Eulalia viridis (Linnaeus, 1767) (2) and Owenia fusiformis (delle Chiaje, 1844) (5), all of them reported from Portugal and frequently used in ecological studies as environmental quality indicators. Our results for these species showed discordance between molecular lineages and morphospecies, or added additional relatively divergent lineages. The potential inaccuracies in environmental assessments, where underpinning polychaete species diversity is poorly resolved or clarified, demands additional and extensive investigation of the DNA barcode diversity in this group, in parallel with alpha taxonomy efforts. %0 dataset %@ %A Riethmüller, R. %D 2016 %J PANGAEA %R doi:10.1594/PANGAEA.859703 %T Continuous thermosalinograph oceanography along HEINCKE cruise track HE331 %U https://doi.org/10.1594/PANGAEA.859703 %X %0 conference object %@ %A Druecker, S., Steglich, D., Merckelbach, L., Werner, A., Bargmann, S. %D 2016 %J Book of Abstracts, GAMM Jahrestagung 2016 %P 481 %T Finite element and simplified analytical calculation of an underwater glider-ship collision %U %X No abstact %0 dataset %@ %A Riethmüller, R., Röttgers, R. %D 2016 %J PANGAEA %R doi:10.1594/PANGAEA.859773 %T Continuous thermosalinograph oceanography along HEINCKE cruise track HE407 %U https://doi.org/10.1594/PANGAEA.859773 %X %0 journal article %@ 0720-213X %A Borges, L.M.S. %D 2016 %J Zoomorphology %N 1 %P 33-41 %R doi:10.1007/s00435-015-0277-4 %T The internal structure of the pallets of Nototeredo norvagica and Psiloteredo megotara (Bivalvia: Teredinidae): implications for subfamilial allocations %U https://doi.org/10.1007/s00435-015-0277-4 1 %X The Teredinidae possess specialised calcareous paddle-like structures, the pallets, which flank the siphons. The external segmentation/non-segmentation of the pallets is used as the main diagnostic character to distinguish between the Teredininae (non-segmented pallet line) and the Bankiinae (segmented pallet line). The internal segmentation of the pallets has, however, seldom been accessed. Therefore, in the present study, the internal structure of the pallets of Psiloteredo megotara (Teredininae) and Nototeredo norvagica (Bankiinae) was analysed using scanning electron microscopy. Pallets of P. megotara were segmented, in a fashion similar to those of N. norvagica, rather than lacking true segmentation as had been reported previously. This finding, affecting a key character state, supports results from previous molecular work and shows the need for further work to ascertain the valid compositions of the Teredininae and Bankiinae. %0 conference object %@ 0831-2796 %A Lobo, J., Teixeira, M.A.L., Borges, L.M.S., Ferreira, M.S.G., Hollatz, C., Gomes, P.A., Sousa, R., Ravara, A., Costa, M.H., Costa, F.O. %D 2015 %J Genome %N 5 %P 247 %R doi:10.1139/gen-2015-0087 %T DNA barcodes of polychaetes (Annelida: Polychaeta) from the southern European Atlantic coast underscores the incipient state of the global reference library for this taxon %U https://doi.org/10.1139/gen-2015-0087 5 %X No abstract %0 conference lecture %@ %A Costa, F.O., Borges, L.M.S., Hollatz, C., Lobo, J., Cunha, A.M., Vilela, A.P., Calado, G., Coelho, R., Costa, A.C., Ferreira, M.S.G., Costa, M.H. %D 2015 %J 6th International Barcode of Life Conference %T Priming a DNA barcode library for marine Gastropoda of the continental Portuguese coast and Azores Islands %U %X %0 conference object %@ 0831-2796 %A Costa, F.O., Borges, L.M.S., Hollatz, C., Lobo, J., Cunha, A.M., Vilela, A.P., Calado, G., Coelho, R., Costa, A.C., Ferreira, M.S.G., Costa, M.H. %D 2015 %J Genome %N 5 %P 207 %R doi:10.1139/gen-2015-0087 %T Priming a DNA barcode library for marine Gastropoda of the continental Portuguese coast and Azores Islands %U https://doi.org/10.1139/gen-2015-0087 5 %X No abstract %0 journal article %@ 0272-7714 %A Voynova, Y.G., Lebaron, K.C., Barnes, R.T., Ullman, W.J. %D 2015 %J Estuarine, Coastal and Shelf Science %P 33-48 %R doi:10.1016/j.ecss.2015.03.027 %T In situ response of bay productivity to nutrient loading from a small tributary: The Delaware Bay-Murderkill Estuary tidally-coupled biogeochemical reactor %U https://doi.org/10.1016/j.ecss.2015.03.027 %X A small, turbid and nutrient-rich tributary, the Murderkill Estuary, and a large estuarine ecosystem, the Delaware Bay, are tightly linked and form an efficient, tidally-coupled biogeochemical reactor during the summer. Nitrate loading from the Murderkill Estuary generates an instantaneous increase in biological oxygen production in the adjacent Delaware Bay. We are able to capture this primary production response with continuous hourly measurements of dissolved oxygen, chlorophyll, and nitrate. The nitrate influxes from the Murderkill support primary production rates in the Delaware Bay margins that are twice as high as the average production rates measured in the central Bay regions. This elevates chlorophyll in the Bay margins in the summer and fuels metabolism. Tidal transport of the newly produced autochthonous chlorophyll particles from the Bay into the Estuary could also provide a source of labile material to the marshes surrounding the Murderkill, thus perhaps fueling marsh respiration. As a consequence of the tidal coupling between Delaware Bay and the Murderkill Estuary, ecosystem productivity and metabolism in the Bay and Estuary are linked, generating an ecosystem feedback mechanism. Storms modulate this tidally-coupled biogeochemical reactor, by generating significant nitrate and salinity changes. Depending on their magnitude and duration, storms induce large phytoplankton blooms in the Delaware Bay. Such large phytoplankton blooms may occur more often with climate change, since century-long discharge records document an increase in storm frequency. %0 journal article %@ 0196-2892 %A Horstmann, J., Falchetti, S., Wackermann, C., Maresca, S., Caruso, M.J., Graber, H.C. %D 2015 %J IEEE Transactions on Geoscience and Remote Sensing %N 5 %P 2887-2898 %R doi:10.1109/TGRS.2014.2366433 %T Tropical Cyclone Winds Retrieved From C-Band Cross-Polarized Synthetic Aperture Radar %U https://doi.org/10.1109/TGRS.2014.2366433 5 %X This paper presents a geophysical model function (GMF) that has been developed to describe the relation of the ocean surface wind with the normalized radar cross section (NRCS) at C-band cross polarization (cross-pol). Synthetic aperture radar (SAR) images have been simultaneously collected at copolarization (co-pol) and cross-pol at moderate to high wind speeds. Using the SAR co-pol retrieved wind fields and an uncertainty estimate of the retrieved wind speeds, the cross-pol dependencies of the NRCS are investigated with respect to wind, incidence angle, and polarization pairs. For wind speeds above 10 m/s, there is a significant dependence of the NRCS on wind speed. However, the SAR cross-pol data are also significantly affected by the noise floor and crosstalk between the channels. Estimates of the noise floor are determined and removed from the NRCS. Three GMFs are developed: the first is for transmission at horizontal (H) polarization and the second at vertical (V) polarization. A third GMF accounts for wind direction dependence. Validation of the GMFs is conducted by comparison with collocated Stepped Frequency Microwave Radiometer (SFMR) data. The resulting bias of -0.7 m/s and standard deviation of 3.7 m/s demonstrate the excellent performance for these GMFs for wind speed retrieval between 10 and 35 m/s. Furthermore, comparisons show that SAR cross-pol retrieved wind speeds are of similar quality as those of SFMR and are significantly better in the moderate to high wind speed regime than SAR co-pol retrieved winds. %0 journal article %@ 0196-2892 %A Vivone, G., Braca, P., Horstmann, J. %D 2015 %J IEEE Transactions on Geoscience and Remote Sensing %N 7 %P 3931-3949 %R doi:10.1109/TGRS.2014.2388355 %T Knowledge-Based Multitarget Ship Tracking for HF Surface Wave Radar Systems %U https://doi.org/10.1109/TGRS.2014.2388355 7 %X These last decades spawned a great interest toward low-power high-frequency (HF) surface-wave (SW) radars for ocean remote sensing. By virtue of their over-the-horizon coverage capability and continuous-time mode of operation, these sensors are also effective long-range early warning tools in maritime situational awareness applications providing an additional source of information for target detection and tracking. Unfortunately, they also exhibit many shortcomings that need to be taken into account, and proper algorithms need to be exploited to overcome their limitations. In this paper, we develop a knowledge-based (KB) multitarget tracking methodology that takes advantage of a priori information on the ship traffic. This a priori information is given by the ship sea lanes and by their related motion models, which together constitute the basic building blocks of a variable structure interactive multiple model procedure. False alarms and missed detections are dealt with using a joint probabilistic data association rule and nonlinearities are handled by means of the unscented Kalman filter. The KB-tracking procedure is validated using real data acquired during an HF-radar experiment in the Ligurian Sea (Mediterranean Sea). Two HFSW radar systems were operated to develop and test target detection and tracking algorithms. The overall performance is defined in terms of time-on-target, false-alarm rate (FAR), track fragmentation (TF), and accuracy. A full statistical characterization is provided using one month of data. A significant improvement of the KB-tracking procedure, in terms of system performance, is demonstrated in comparison with a standard joint probabilistic data association tracker recently proposed in the literature to track HFSW radar data. The main improvement of our approach is the better capability of following targets without increasing the FAR. This increment is much more evident in the region of low FAR, where it can be over the 30% for both the HF- W radar systems. The KB-tracking exhibits on average a reduction of the TF of about the 20% and the 13% of the utilized HFSW-radar systems. %0 journal article %@ 0143-1161 %A Alpers, W., Mouche, A., Horstmann, J., Ivanov, A.Y., Barabanov, V.S. %D 2015 %J International Journal of Remote Sensing %N 3 %P 863-881 %R doi:10.1080/01431161.2014.999169 %T Application of a new algorithm using Doppler information to retrieve complex wind fields over the Black Sea from ENVISAT SAR images %U https://doi.org/10.1080/01431161.2014.999169 3 %X Several algorithms have been proposed to retrieve near-surface wind fields from C-band synthetic aperture radar (SAR) images acquired over the ocean. They mainly differ in the way they retrieve the wind direction. Conventionally, the wind direction is taken from atmospheric models or is extracted from the linear features sometimes visible in SAR images. Recently, a new wind retrieval algorithm has been proposed, which also includes the Doppler shift induced by motions of the sea surface. In this article, we apply three wind retrieval algorithms, including the one using Doppler information, to three complex wind events encountered over the Black Sea and compare the SAR-derived wind fields with model wind fields calculated using the high-resolution weather research and forecasting (WRF) model. It is shown that the new algorithm is very efficient in resolving the 180° ambiguity in the wind direction, which is often a problem in the streak-based wind retrieval algorithms. However, the Doppler-based algorithm only yields good results for wind directions that have a significant component in the look direction of the SAR antenna. Furthermore, it is dependent on good separation of the contributions to the Doppler shift induced by surface currents and wind-related effects (wind drift and wind-sea components of the ocean wave spectrum). We conclude that an optimum wind retrieval algorithm should consist of a combination of the algorithms based on linear features and Doppler information. %0 journal article %@ 2052-4463 %A Sharma, S., Gray, D.K., Read, J.S., O’Reilly, C.M., Schneider, P., Qudrat, A., Gries, C., Stefanoff, S., Hampton, S.E., Hook, S., Lenters, J.D., Livingstone, D.M., McIntyre, P.B., Adrian, R., Allan, M.G., Anneville, O., Arvola, L., Austin, J., Bailey, J., Baron, J.S., Brookes, J., Chen, Y., Daly, R., Dokulil, M., Dong, B., Ewing, K., de Eyto, E., Hamilton, D., Havens, K., Haydon, S., Hetzenauer, H., Heneberry, J., Hetherington, A.L., Higgins, S.N., Hixson, E., Izmest’eva, L.R., Jones, B.M., Kangur, K., Kasprzak, P., Koester, O., Kraemer, B.M., Kumagai, M., Kuusisto, E., Leshkevich, G., May, L., MacIntyre, S., Mueller-Navarra, D., Naumenko, M., Noges, P., Noges, T., Niederhauser, P.North, R.P., Paterson, A.M., Plisnier, P.-D., Rigosi, A., Rimmer, A., Rogora, M., Rudstam, L., Rusak, J.A., Salmaso, N., Samal, N.R., Schindler, D.E., Schladow, G., Schmidt, S.R., Schultz, T., Silow, E.A., Straile, D., Teubner, K., Verburg, P., Voutilainen, A., Watkinson, A., Weyhenmeyer, G.A., Williamson, C.E., Woo, K.H. %D 2015 %J Scientific Data %P 150008 %R doi:10.1038/sdata.2015.8 %T A global database of lake surface temperatures collected by in situ and satellite methods from 1985–2009 %U https://doi.org/10.1038/sdata.2015.8 %X Global environmental change has influenced lake surface temperatures, a key driver of ecosystem structure and function. Recent studies have suggested significant warming of water temperatures in individual lakes across many different regions around the world. However, the spatial and temporal coherence associated with the magnitude of these trends remains unclear. Thus, a global data set of water temperature is required to understand and synthesize global, long-term trends in surface water temperatures of inland bodies of water. We assembled a database of summer lake surface temperatures for 291 lakes collected in situ and/or by satellites for the period 1985–2009. In addition, corresponding climatic drivers (air temperatures, solar radiation, and cloud cover) and geomorphometric characteristics (latitude, longitude, elevation, lake surface area, maximum depth, mean depth, and volume) that influence lake surface temperatures were compiled for each lake. This unique dataset offers an invaluable baseline perspective on global-scale lake thermal conditions as environmental change continues. %0 journal article %@ 2249-0205 %A Jahnke, B., Frank, C., Fernandez, J.F., Niemeyer, B. %D 2015 %J American Chemical Science Journal %N 2 %P 163-173 %R doi:10.9734/ACSj/2015/13089 %T A Sequential Injection Analysis Method for the Determination of Glyphosate and Aminomethylphosphonic Acid in Water Samples %U https://doi.org/10.9734/ACSj/2015/13089 2 %X A conventional laboratory method for the determination of glyphosate and its degradation product aminomethylphosphonic acid (AMPA) is high performance liquid chromatography (HPLC) followed by post column derivatization with o-phthaldialdehyde (OPA). However, AMPA is partly decomposed in the process causing a deviation in the AMPA detection or even making a simultaneous detection of glyphosate and AMPA with the described postcolumn procedure impossible. We used a compact sequential injection analysis system and optimized the process conditions for both analytes independently from each other. The process conditions were adjusted to the different chemical characteristics of AMPA (primary amine) and glyphosate (secondary amine), which needs to be oxidized to a primary amine prior to the derivatization. An ion exchange column was included in the system to eliminate amines interfering with the method. Limits of detection of 16 and 9 µg L-1 for glyphosate and AMPA, respectively are similar to those achieved with HPLC methods reported in literature, but compared to conventional HPLC methods only small amounts of reagents are consumed. %0 journal article %@ 1866-3508 %A Nechad, B., Ruddick, K., Schroeder, T., Oubelkheir, K., Blondeau-Patissier, D., Cherukuru, N., Brando, V., Dekker, A., Clementson, L., Banks, A.C., Maritorena, S., Werdell, J., Sa, C., Brotas, V., Caballero de Frutos, I., Ahn, Y.-H., Salama, S., Tilstone, G., Martinez-Vicente, V., Foley, D., McKibben, M., Nahorniak, J., Peterson, T., Silio-Calzada, A., Roettgers, R., Lee, Z., Peters, M., Brockmann, C. %D 2015 %J Earth System Science Data %N 2 %P 319-348 %R doi:10.5194/essd-7-319-2015 %T CoastColour Round Robin data sets: a database to evaluate the performance of algorithms for the retrieval of water quality parameters in coastal waters %U https://doi.org/10.5194/essd-7-319-2015 2 %X The data sets mainly consist of 6484 marine reflectance (either multispectral or hyperspectral) associated with various geometrical (sensor viewing and solar angles) and sky conditions and water constituents: total suspended matter (TSM) and chlorophyll a (CHL) concentrations, and the absorption of coloured dissolved organic matter (CDOM). Inherent optical properties are also provided in the simulated data sets (5000 simulations) and from 3054 match-up locations. The distributions of reflectance at selected MERIS bands and band ratios, CHL and TSM as a function of reflectance, from the three data sets are compared. Match-up and in situ sites where deviations occur are identified. The distributions of the three reflectance data sets are also compared to the simulated and in situ reflectances used previously by the International Ocean Colour Coordinating Group (IOCCG, 2006) for algorithm testing, showing a clear extension of the CCRR data which covers more turbid waters. %0 journal article %@ 0148-0227 %A Purkiani, K., Becherer, J., Floeser, G., Graewe, U., Mohrholz, V., Schuttelaars, H.M., Burchard, H. %D 2015 %J Journal of Geophysical Research : Oceans %N 1 %P 225-243 %R doi:10.1002/2014JC010325 %T Numerical analysis of stratification and destratification processes in a tidally energetic inlet with an ebb tidal delta %U https://doi.org/10.1002/2014JC010325 1 %X Stratification and destratification processes in a tidally energetic, weakly stratified inlet in the Wadden Sea (south eastern North Sea) are investigated in this modeling study. Observations of current velocity and vertical density structure show strain-induced periodic stratification for the southern shoal of the tidal channel. In contrast to this, in the nearby central region of the channel, increased stratification is already observed directly after full flood. To investigate the processes leading to this different behavior, a nested model system using GETM is set up and successfully validated against field data. The simulated density development along a cross section that includes both stations shows that cross-channel stratification is strongly increasing during flood, such that available potential energy is released in the deeper part of the channel during flood. An analysis of the potential energy anomaly budget confirms that the early onset of vertical stratification during flood at the deeper station is mainly controlled by the stratifying cross-channel straining of the density field. In contrast to this, in the shallow part of the channel, the relatively weak cross-channel straining is balanced by along-channel straining and vertical mixing. An idealized analytical model confirms the following hypothesis: The laterally convergent flood current advecting laterally stratified water masses from the shallow and wide ebb tidal delta to the deep and narrow tidal channel has the tendency to substantially increase cross-channel density gradients in the tidal channel. This process leads to stratification during flood. %0 journal article %@ 0885-8985 %A Braca, P., Maresca, S., Grasso, R., Bryan, K., Horstmann, J. %D 2015 %J IEEE Aerospace and Electronic Systems Magazine %N 12 %P 4-18 %R doi:10.1109/MAES.2015.150004 %T Maritime surveillance with multiple over-the-horizon HFSW radars: An overview of recent experimentation %U https://doi.org/10.1109/MAES.2015.150004 12 %X Maritime surveillance (MS) is an important domain for many national and international institutions, agencies, and bodies. In this context, the MS initiatives are aimed to enhance search and rescue operations, provide effective response to accidents and disasters, monitor fisheries, prevent pollution and support law enforcement and national defence. This means that it is of vital importance to generate real-time wide-area maritime operational pictures. However, many are the issues at stake. For instance, deriving mission planning tools with multiple stakeholders and achieving coverage with a wide choice of platforms (coastal, airborne and satellite) are just some of the problems. In addition, it could be required to correlate results with intelligence data and to integrate radar systems with the automatic identification system (AIS) and vessel traffic services (VTS). Other issues could be providing navigational risk detection to support operators, as well as improving resource allocation for greater efficiency and cost savings. Having access to other services, such as weather and environment information, could be precious for route planning. Additionally, timely and robust ways of sharing data and information between the authorities need to be developed with the objective of maximizing the sustainable use of oceans and seas, while enhancing the knowledge and innovation potential in maritime affairs. %0 journal article %@ 1385-1101 %A Wollschlaeger, J., Wiltshire, K.H., Petersen, W., Metfies, K. %D 2015 %J Journal of Sea Research %P 83-96 %R doi:10.1016/j.seares.2015.02.005 %T Analysis of phytoplankton distribution and community structure in the German Bight with respect to the different size classes %U https://doi.org/10.1016/j.seares.2015.02.005 %X Microphytoplankton was identified as the major contributor to biomass in all seasons, followed by the nanophytoplankton. Generally, biomass distribution was patchy, but the overall contribution of small phytoplankton was higher in offshore areas and also in areas exhibiting higher turbidity. Regarding temporal development of the community, differences between the small phytoplankton community and the microphytoplankton were found. The latter exhibited a seasonal pattern regarding number of taxa present, alpha- and beta-diversity, and community structure, while for the nano- and especially the picophytoplankton, a general shift in the community between both years was observable without seasonality. Although the reason for this shift remains unclear, the results imply a different response of large and small phytoplankton to environmental influences. %0 conference lecture %@ %A Seemann, J., Horstmann, J., Leuder, L., Senet, C., Baschek, B. %D 2015 %J 11th Current, Waves and Turbulence Measurement Workshop, CWTM 2015 %T Accuracy of Wave Direction Estimation from Directional Wave Rider Buoy Time Series %U %X %0 conference lecture (invited) %@ %A Breitbach, G. %D 2015 %J Large-Scale Data Management & Analysis, LSDMA Community Forum %T Data Management in the Coastal Observing System COSYNA %U %X %0 conference lecture %@ %A Horstmann, J., Carrasco, R., Seemann, J., Cysewski, M. %D 2015 %J 11th Current, Waves and Turbulence Measurement Workshop, CWTM 2015 %T Surface Current Measurements Using Marine Radars %U %X %0 conference lecture %@ %A Vivone, G., Braca, P., Horstmann, J. %D 2015 %J Oceans 2015 %T Variable Structure Interacting Multiple Model Algorithm for Ship Tracking Using HF Surface Wave Radar Data %U %X %0 conference lecture %@ %A Lobo, J., Teixeira, M.A.L., Borges, L.M.S., Ferreira, M.S.G., Hollatz, C., Gomes, P.A., Sousa, R., Ravara, A., Costa, M.H., Costa, F.O. %D 2015 %J 6th International Barcode of Life Conference %T DNA barcodes of polychaetes (Annelida: Polychaeta) from the southern European Atlantic coast underscores the incipient state of the global reference library for this taxon %U %X %0 journal article %@ 1463-5003 %A Brix, H., Menemenlis, D., Hill, C., Dutkiewicz, S., Jahn, O., Wang, D., Bowman, K., Zhang, H. %D 2015 %J Ocean Modelling %P 1-14 %R doi:10.1016/j.ocemod.2015.07.008 %T Using Green’s Functions to initialize and adjust a global, eddying ocean biogeochemistry general circulation model %U https://doi.org/10.1016/j.ocemod.2015.07.008 %X The NASA Carbon Monitoring System (CMS) Flux Project aims to attribute changes in the atmospheric accumulation of carbon dioxide to spatially resolved fluxes by utilizing the full suite of NASA data, models, and assimilation capabilities. For the oceanic part of this project, we introduce ECCO2-Darwin, a new ocean biogeochemistry general circulation model based on combining the following pre-existing components: (i) a full-depth, eddying, global-ocean configuration of the Massachusetts Institute of Technology general circulation model (MITgcm), (ii) an adjoint-method-based estimate of ocean circulation from the Estimating the Circulation and Climate of the Ocean, Phase II (ECCO2) project, (iii) the MIT ecosystem model “Darwin”, and (iv) a marine carbon chemistry model. Air–sea gas exchange coefficients and initial conditions of dissolved inorganic carbon, alkalinity, and oxygen are adjusted using a Green’s Functions approach in order to optimize modeled air–sea CO2 fluxes. Data constraints include observations of carbon dioxide partial pressure (pCO2) for 2009–2010, global air–sea CO2 flux estimates, and the seasonal cycle of the Takahashi et al. (2009) Atlas. The model sensitivity experiments (or Green’s Functions) include simulations that start from different initial conditions as well as experiments that perturb air–sea gas exchange parameters and the ratio of particulate inorganic to organic carbon. The Green’s Functions approach yields a linear combination of these sensitivity experiments that minimizes model-data differences. The resulting initial conditions and gas exchange coefficients are then used to integrate the ECCO2-Darwin model forward. Despite the small number (six) of control parameters, the adjusted simulation is significantly closer to the data constraints (37% cost function reduction, i.e., reduction in the model-data difference, relative to the baseline simulation) and to independent observations (e.g., alkalinity). The adjusted air–sea gas exchange parameter differs by only 3% from the baseline value and has little impact (−0.1−0.1%) on the cost function. The particulate inorganic to organic carbon ratio was increased more than threefold and reduced the cost function by 22% relative to the baseline integration, indicating a significant influence of biology on air–sea gas exchange. The largest contribution to cost reduction (35%) comes from the adjustment of initial conditions. In addition to reducing biases relative to observations, the adjusted simulation exhibits smaller model drift than the baseline. We estimate drift by integrating the model with repeated 2009 atmospheric forcing for seven years and find a volume-weighted drift reduction of, for example, 12.5% for nitrate and 30% for oxygen in the top 300 m. Although there remain several regions with large model-data discrepancies, for example, overly strong carbon uptake in the Southern Ocean, the adjusted simulation is a first step towards a more accurate representation of the ocean carbon cycle at high spatial and temporal resolution. %0 journal article %@ 0034-4257 %A Mueller, D., Krasemann, H., Brewin, R.J.W., Brockmann, C., Deschamps, P.-Y., Doerffer, R., Fomferra, N., Franz, B.A., Grant, M.G., Groom, S.B., Melin, F., Platt, T., Regner, P., Sathyendranath, S., Steinmetz, F., Swinton, J. %D 2015 %J Remote Sensing of Environment %P 242-256 %R doi:10.1016/j.rse.2013.11.026 %T The Ocean Colour Climate Change Initiative: I. A methodology for assessing atmospheric correction processors based on in-situ measurements %U https://doi.org/10.1016/j.rse.2013.11.026 %X The Ocean Colour Climate Change Initiative intends to provide a long-term time series of ocean colour data and investigate the detectable climate impact. A reliable and stable atmospheric correction procedure is the basis for ocean colour products of the necessary high quality. In order to guarantee an objective selection from a set of four atmospheric correction processors, the common validation strategy of comparisons between in-situ and satellite-derived water leaving reflectance spectra, is extended by a ranking system. In principle, the statistical parameters such as root mean square error, bias, etc. and measures of goodness of fit, are transformed into relative scores, which evaluate the relationship of quality dependent on the algorithms under study. The sensitivity of these scores to the selected database has been assessed by a bootstrapping exercise, which allows identification of the uncertainty in the scoring results. Although the presented methodology is intended to be used in an algorithm selection process, this paper focusses on the scope of the methodology rather than the properties of the individual processors. %0 conference poster %@ %A North, R., Moeller, K.O., Karimova, S., Cisewski, B., Floeter, J., Riethmueller, R., Baschek, B. %D 2015 %J 26th General Assembly of the International Union of Geodesy and Geophysics, IUGG 2015 %T Horizontal scales and structures of the temperature and chlorophyll fluorescence fields in the German Bight %U %X %0 conference paper %@ %A Vivone, G., Braca, P., Horstmann, J. %D 2015 %J Conference Publications - Oceans 2015 %P 1-8 %R doi:10.1109/OCEANS-Genova.2015.7271644 %T Variable Structure Interacting Multiple Model Algorithm for Ship Tracking Using HF Surface Wave Radar Data %U https://doi.org/10.1109/OCEANS-Genova.2015.7271644 %X These last decades spawned a great interest towards low-power High-Frequency (HF) Surface-Wave (SW) radars for ocean remote sensing. By virtue of their over-the-horizon coverage capability and continuous-time mode of operation, these sensors are also effective long-range early-warning tools in maritime situational awareness applications. In this paper we show how it is possible to take advantage of a priori information on traffic by the means of a knowledge-based multi-target tracking algorithm, demonstrating that the tracking stage can be enhanced by combining on-line data from the HFSW radar with ship traffic information. A significant improvement of the proposed procedure, in terms of system performance, is demonstrated in comparison with the state-of-the-art approach recently presented in the literature. The main benefit of our approach is the ability to better follow targets without increasing the false alarm rate. The ability to follow targets can be over 30% better than existing methods. The proposed approach also exhibits a reduction of the track fragmentation. Average gains between the 13% and the 20% are observed. %0 journal article %@ 0003-6935 %A Tan, H., Oishi, T., Tanaka, A., Doerffer, R. %D 2015 %J Applied Optics %N 25 %P 7718-7733 %R doi:10.1364/AO.54.007718 %T Accurate estimation of the backscattering coefficient by light scattering at two backward angles %U https://doi.org/10.1364/AO.54.007718 25 %X Backscattering coefficients are frequently estimated from light scattering at one backward angle multiplied by a conversion factor. We determined that the shapes of the volume scattering functions (VSFs), particularly for scattering angles larger than 170°, cause significant variations in the conversion factor at 120°. Our approach uses the ratio of scattering at 170° and at 120°, which is a good indicator of the shape differences of the VSFs for most oceanic waters and wavelengths in the visible range. The proposed method provides significant accuracy improvement in the determination of the backscattering coefficients with a prediction error of 3% of the mean. %0 conference paper %@ %A Horstmann, J., Carrasco, R., Seemann, J., Cysewski, M. %D 2015 %J Conference Proceedings, 11th Current, Waves and Turbulence Measurement Workshop, CWTM 2015 %R doi:10.1109/CWTM.2015.7098139 %T Surface Current Measurements Using Marine Radars %U https://doi.org/10.1109/CWTM.2015.7098139 %X Within this paper we investigate the possibilities of measuring surface currents utilizing incoherent and coherent microwave radar operating at X-band near grazing incidence. The measured radar backscatter enables to measure the surface waves in space and time and therefore the surface current via the dispersion relation of surface waves. The Doppler velocities measured by the radar are modulated by contributions from the wind, current as well as waves and therefore enable to obtain additional information on the surface currents and surface waves. %0 conference paper %@ %A Seemann, J., Horstmann, J., Leuder, L., Senet, C., Baschek, B. %D 2015 %J Conference Proceedings, 11th Current, Waves and Turbulence Measurement Workshop, CWTM 2015 %R doi:10.1109/CWTM.2015.7098137 %T Accuracy of Wave Direction Estimation from Directional Wave Rider Buoy Time Series %U https://doi.org/10.1109/CWTM.2015.7098137 %X The directionality of single-wave events measured with a directional waverider buoy is analyzed. The method used for directionality analysis is presented and an estimation of the achievable accuracy, based on the bootstrap method is given. %0 journal article %@ 2072-4292 %A Guanter, L., Kaufmann, H., Segl, K., Foerster, S., Rogass, C., Chabrillat, S., Kuester, T., Hollstein, A., Rossner, G., Chlebek, C., Straif, C., Fischer, S., Schrader, S., Storch, T., Heiden, U., Mueller, A., Bachmann, M., Muehle, H., Mueller, R., Habermeyer, M., Ohndorf, A., Hill, J., Buddenbaum, H., Hostert, P., Linden, S.van der, Leitao, P.J., Rabe, A., Doerffer, R., Krasemann, H., Xi, H., Mauser, W., Hank, T., Locherer, M., Rast, M., Staenz, K., Sang, B. %D 2015 %J Remote Sensing %N 7 %P 8830-8857 %R doi:10.3390/rs70708830 %T The EnMAP Spaceborne Imaging Spectroscopy Mission for Earth Observation %U https://doi.org/10.3390/rs70708830 7 %X Imaging spectroscopy, also known as hyperspectral remote sensing, is based on the characterization of Earth surface materials and processes through spectrally-resolved measurements of the light interacting with matter. The potential of imaging spectroscopy for Earth remote sensing has been demonstrated since the 1980s. However, most of the developments and applications in imaging spectroscopy have largely relied on airborne spectrometers, as the amount and quality of space-based imaging spectroscopy data remain relatively low to date. The upcoming Environmental Mapping and Analysis Program (EnMAP) German imaging spectroscopy mission is intended to fill this gap. An overview of the main characteristics and current status of the mission is provided in this contribution. The core payload of EnMAP consists of a dual-spectrometer instrument measuring in the optical spectral range between 420 and 2450 nm with a spectral sampling distance varying between 5 and 12 nm and a reference signal-to-noise ratio of 400:1 in the visible and near-infrared and 180:1 in the shortwave-infrared parts of the spectrum. EnMAP images will cover a 30 km-wide area in the across-track direction with a ground sampling distance of 30 m. An across-track tilted observation capability will enable a target revisit time of up to four days at the Equator and better at high latitudes. EnMAP will contribute to the development and exploitation of spaceborne imaging spectroscopy applications by making high-quality data freely available to scientific users worldwide. %0 conference lecture %@ %A Puillat, I., Farcy, P., Durand, D., Petihakis, G., Morin, P., Kriegger, M., Petersen, W., Tintore, J., Soerensen, K., Sparnocchia, S., Wehde, H. %D 2015 %J Marine Technology Society and the IEEE Oceanic Engineering Society Conference, OCEANS 2015 %T Strategy for sustainability of the Joint European Research Infrastructure Network for Coastal Observatories - JERICO %U %X %0 conference lecture %@ %A Petihakis, G., Petersen, W., Nair, R., Faimali, M., Pavanello, G., Boukerma, K., Delauney, L., Puillat, I., Farcy, P., Greenwood, N. %D 2015 %J Marine Technology Society and the IEEE Oceanic Engineering Society Conference, OCEANS 2015 %T Harmonization in the Joint European Research Infrastructure Network for Coastal Observatories - JERICO %U %X %0 conference paper %@ %A Puillat, I., Farcy, P., Durand, D., Petihakis, G., Morin, P., Kriegger, M., Petersen, W., Tintore, J., Sorensen, K., Sparnocchia, S., Wehde, H. %D 2015 %J Conference Publications, OCEANS 2015 - MTS/IEEE Washington %P 1-8 %R doi:10.23919/OCEANS.2015.7404530 %T Strategy for sustainability of the Joint European Research Infrastructure Network for Coastal Observatories - JERICO %U https://doi.org/10.23919/OCEANS.2015.7404530 %X The JERICO European research infrastructure (RI) is integrating several platform types i.e. fixed buoys, piles, moorings, drifters, Ferryboxes, gliders, HF radars, coastal cable observatories and the associated technologies dedicated to the observation and monitoring of the European coastal seas. The infrastructure is to serve both the implementation of European marine policies and the elucidation of key scientific questions through dedicated observation and monitoring plans. It includes observations of the physical, chemical and biological compartments and aims at a better integration of marine biology with physical and chemical oceanology, through specific interactions with other relevant ocean observing systems that provide complementary observations. The first phase of the implementation of JERICO encompasses setting up, coordination and harmonization, and were performed between 2011 and 2015 in the framework of FP7-JERICO (www.jerico-fp7.eu), a 4-year long infrastructure project co-funded by the European Commission, with 27 partners from 17 European countries under the coordination of IFREMER. The next 4-year phase is to be carried out through the H2020-JERICO-NEXT European project, starting in 2015 and involving 33 scientific and industrial partners. The main objective of the JERICO consortium is to establish a common approach for a pan-European coastal marine observatory network. This is a dynamic and long-lasting effort necessitating continuous work towards harmonization (i.e. design, operation, and maintenance), evolution and extension of the current systems as well as the delivery of data and products to the users. Success relies on a good coordination and follow-up between FP7-JERICO and JERICO-NEXT, and onwards, at both hardware and software levels. More specifically, the existing network and its possible evolution are continuously assessed taking in account the evolution of the user needs, the harmonization effort to be driven, the existing sensors and- technologies, their upgrades for integration on dedicated platforms, also the accompanying of under development sensors and/or systems with involvement of providers and stakeholders when possible. Nevertheless, a major issue relates to the sustainability of the infrastructure, both at economical and governance levels, and the capability in integrating the latest technology while preserving the scientific value of the data. This paper briefly summarizes the work carried out in FP7-JERICO project and drafts strategic aspects of the JERICO-RI sustainability on the long-term. s. We will present the 6 priority scientific areas that are the drivers of JERICO-NEXT scientific strategy and the subsequent technology development to be implemented through dedicated Joint Research Activity Projects. Emphasis is put on how the consortium intends to address long term financial and legal governance structures for the sustainable implementation of JERICO-NEXT infrastructures, as well as access to the infrastructure and associated services and link to stakeholders such as relevant funding agencies and SMEs. %0 journal article %@ 2072-4292 %A Xi, H., Hieronymi, M., Roettgers, R., Krasemann, H., Qiu, Z. %D 2015 %J Remote Sensing %N 11 %P 14781-14805 %R doi:10.3390/rs71114781 %T Hyperspectral Differentiation of Phytoplankton Taxonomic Groups: A Comparison between Using Remote Sensing Reflectance and Absorption Spectra %U https://doi.org/10.3390/rs71114781 11 %X The emergence of hyperspectral optical satellite sensors for ocean observation provides potential for more detailed information from aquatic ecosystems. The German hyperspectral satellite mission EnMAP (enmap.org) currently in the production phase is supported by a project to explore the capability of using EnMAP data and other future hyperspectral data from space. One task is to identify phytoplankton taxonomic groups. To fulfill this objective, on the basis of laboratory-measured absorption coefficients of phytoplankton cultures (aph(λ)) and corresponding simulated remote sensing reflectance spectra (Rrs(λ)), we examined the performance of spectral fourth-derivative analysis and clustering techniques to differentiate six taxonomic groups. We compared different sources of input data, namely aph(λ), Rrs(λ), and the absorption of water compounds obtained from inversion of the Rrs(λ)) spectra using a quasi-analytical algorithm (QAA). Rrs(λ) was tested as it can be directly obtained from hyperspectral sensors. The last one was tested as expected influences of the spectral features of pure water absorption on Rrs(λ) could be avoided after subtracting it from the inverted total absorption. Results showed that derivative analysis of measured aph(λ) spectra performed best with only a few misclassified cultures. Based on Rrs(λ) spectra, the accuracy of this differentiation decreased but the performance was partly restored if wavelengths of strong water absorption were excluded and chlorophyll concentrations were higher than 1 mg∙m−3. When based on QAA-inverted absorption spectra, the differentiation was less precise due to loss of information at longer wavelengths. This analysis showed that, compared to inverted absorption spectra from restricted inversion models, hyperspectral Rrs(λ) is potentially suitable input data for the differentiation of phytoplankton taxonomic groups in prospective EnMAP applications, though still a challenge at low algal concentrations. %0 journal article %@ 0034-4257 %A Mueller, D., Krasemann, H., Brewin, R.J.W., Brockmann, C., Deschamps, P.-Y., Doerffer, R., Fomferra, N., Franz, B.A., Grant, M.G., Groom, S.B., Melin, F., Platt, T., Regner, P., Sathyendranath, S., Steinmetz, F., Swinton, J. %D 2015 %J Remote Sensing of Environment %P 257-270 %R doi:10.1016/j.rse.2015.01.033 %T The Ocean Colour Climate Change Initiative: II. Spatial and temporal homogeneity of satellite data retrieval due to systematic effects in atmospheric correction processors %U https://doi.org/10.1016/j.rse.2015.01.033 %X Although the need for discussion remains concerning the absolutes by which to judge an AC processor, this example demonstrates clearly, that relying on the match-up analysis alone can lead to misjudgement. %0 journal article %@ 1812-0784 %A Haller, M., Janssen, F., Siddorn, J., Petersen, W., Dick, S. %D 2015 %J Ocean Science %N 6 %P 879-896 %R doi:10.5194/os-11-879-2015 %T Evaluation of numerical models by FerryBox and fixed platform in situ data in the southern North Sea %U https://doi.org/10.5194/os-11-879-2015 6 %X For understanding and forecasting of hydrodynamics in coastal regions, numerical models have served as an important tool for many years. In order to assess the model performance, we compared simulations to observational data of water temperature and salinity. Observations were available from FerryBox transects in the southern North Sea and, additionally, from a fixed platform of the MARNET network. More detailed analyses have been made at three different stations, located off the English eastern coast, at the Oyster Ground and in the German Bight. FerryBoxes installed on ships of opportunity (SoO) provide high-frequency surface measurements along selected tracks on a regular basis. The results of two operational hydrodynamic models have been evaluated for two different time periods: BSHcmod v4 (January 2009 to April 2012) and FOAM AMM7 NEMO (April 2011 to April 2012). While they adequately simulate temperature, both models underestimate salinity, especially near the coast in the southern North Sea. Statistical errors differ between the two models and between the measured parameters. The root mean square error (RMSE) of water temperatures amounts to 0.72 °C (BSHcmod v4) and 0.44 °C (AMM7), while for salinity the performance of BSHcmod is slightly better (0.68 compared to 1.1). The study results reveal weaknesses in both models, in terms of variability, absolute levels and limited spatial resolution. Simulation of the transition zone between the coasts and the open sea is still a demanding task for operational modelling. Thus, FerryBox data, combined with other observations with differing temporal and spatial scales, can serve as an invaluable tool not only for model evaluation, but also for model optimization by assimilation of such high-frequency observations. %0 conference lecture %@ %A Antunes, I.C., Ferreira, M.S., Lobo, J., Teixeira, M.A.L., Borges, L.M.S., Sousa, R., Gomes, P.A., Costa, M.H., Cunha, M.R., Costa, F.O. %D 2015 %J 6th International Barcode of Life Conference %T Comparison between morphological and DNA barcode-suggested species boundaries among shallow-water amphipod fauna from the southern European Atlantic coast %U %X %0 conference lecture %@ %A North, R., Baschek, B., Smith, G., Angel-Benavides, I.M., Miller, D., Riethmueller, R., Marmorino, G. %D 2015 %J 26th General Assembly of the International Union of Geodesy and Geophysics, IUGG 2015 %T Quantifying the kinetic and potential energy of a submesoscale eddy from in situ and aerial observations %U %X %0 journal article %@ 0078-3234 %A Su, J., Tian, T., Krasemann, H., Schartau, M., Wirtz, K. %D 2015 %J Oceanologia %N 4 %P 328-341 %R doi:10.1016/j.oceano.2015.06.001 %T Response patterns of phytoplankton growth to variations in resuspension in the German Bight revealed by daily MERIS data in 2003 and 2004 %U https://doi.org/10.1016/j.oceano.2015.06.001 4 %X Chlorophyll (chl a) concentration in coastal seas exhibits variability on various spatial and temporal scales. Resuspension of particulate matter can somewhat limit algal growth, but can also enhance productivity because of the intrusion of nutrient-rich pore water from sediments or bottom water layers into the whole water column. This study investigates whether characteristic changes in net phytoplankton growth can be directly linked to resuspension events within the German Bight. Satellite-derived chl a were used to derive spatial patterns of net rates of chl a increase/decrease (NR) in 2003 and 2004. Spatial correlations between NR and mean water column irradiance were analysed. High correlations in space and time were found in most areas of the German Bight (R2 > 0.4), suggesting a tight coupling between light availability and algal growth during spring. These correlations were reduced within a distinct zone in the transition between shallow coastal areas and deeper offshore waters. In summer and autumn, a mismatch was found between phytoplankton blooms (chl a > 6 mg m−3) and spring-tidal induced resuspension events as indicated by bottom velocity, suggesting that there is no phytoplankton resuspension during spring tides. It is instead proposed here that frequent and recurrent spring-tidal resuspension events enhance algal growth by supplying remineralized nutrients. This hypothesis is corroborated by a lag correlation analysis between resuspension events and in-situ measured nutrient concentrations. This study outlines seasonally different patterns in phytoplankton productivity in response to variations in resuspension, which can serve as a reference for modelling coastal ecosystem dynamics. %0 journal article %@ 0022-3670 %A Pemberton, P., Nilsson, J., Hieronymus, M., Meier, H.E.M. %D 2015 %J Journal of Physical Oceanography %N 4 %P 1025-1050 %R doi:10.1175/JPO-D-14-0197.1 %T Arctic Ocean Water Mass Transformation in S–T Coordinates %U https://doi.org/10.1175/JPO-D-14-0197.1 4 %X In this paper, water mass transformations in the Arctic Ocean are studied using a recently developed salinity–temperature (S–T) framework. The framework allows the water mass transformations to be succinctly quantified by computing the surface and internal diffusive fluxes in S–T coordinates. This study shows how the method can be applied to a specific oceanic region, in this case the Arctic Ocean, by including the advective exchange of water masses across the boundaries of the region. Based on a simulation with a global ocean circulation model, the authors examine the importance of various parameterized mixing processes and surface fluxes for the transformation of water across isohaline and isothermal surfaces in the Arctic Ocean. The model-based results reveal a broadly realistic Arctic Ocean where the inflowing Atlantic and Pacific waters are primarily cooled and freshened before exiting back to the North Atlantic. In the model, the water mass transformation in the T direction is primarily accomplished by the surface heat flux. However, the surface freshwater flux plays a minor role in the transformation of water toward lower salinities, which is mainly driven by a downgradient mixing of salt in the interior ocean. Near the freezing line, the seasonal melt and growth of sea ice influences the transformation pattern. %0 conference paper %@ %A Maresca, S., Braca, P., Grasso, R., Horstmann, J. %D 2015 %J Conference Publications - Oceans 2015 %P 1-5 %R doi:10.1109/OCEANS-Genova.2015.7271676 %T The Impact of Sea State on HF Surface-Wave Radar Ship Detection and Tracking Performance %U https://doi.org/10.1109/OCEANS-Genova.2015.7271676 %X Nowadays, we face an ever increasing interest in new technologies and solutions for the maritime surveillance (MS) domain. In such a context, oceanographic high-frequency surface-wave (HFSW) radars have started to get significant attention. In fact, they are operated to provide remote sensing information of wide open-sea areas, but they may also contribute with useful cost-effective track-based information to current operational MS systems. In this paper, specific interest is devoted to the analysis of the system detection and tracking capabilities under different meteo-oceanographic (METOC) conditions. Experimental data are acquired by three HFSW radars operated by the Helmholtz Zentrum Geesthacht (HZG) at the German Bight, North Sea, within the Coastal Observing System for Northern and Arctic Seas (COSYNA). Here, they operationally retrieve continuous sea state and currents. In this work, ship reports from the Automatic Identication System (AIS) are the ground truth information used for evaluating HFSW radar system capabilities, while METOC data are directly acquired from COSYNA. Preliminary results are presented and discussed, together with outlines for future research. %0 conference object %@ 0831-2796 %A Antunes, I.C., Ferreira, M.S., Lobo, J., Teixeira, M.A.L., Borges, L.M.S., Sousa, R., Gomes, P.A., Costa, M.H., Cunha, M.R., Costa, F.O. %D 2015 %J Genome %N 5 %P 187 %R doi:10.1139/gen-2015-0087 %T Comparison between morphological and DNA barcode-suggested species boundaries among shallow-water amphipod fauna from the southern European Atlantic coast %U https://doi.org/10.1139/gen-2015-0087 5 %X No abstract %0 journal article %@ 2072-4292 %A Shen, C., Huang, W., Gill, E.W., Carrasco, R., Horstmann, J. %D 2015 %J Remote Sensing %N 6 %P 7753-7767 %R doi:10.3390/rs70607753 %T An Algorithm for Surface Current Retrieval from X-band Marine Radar Images %U https://doi.org/10.3390/rs70607753 6 %X In this paper, a novel current inversion algorithm from X-band marine radar images is proposed. The routine, for which deep water is assumed, begins with 3-D FFT of the radar image sequence, followed by the extraction of the dispersion shell from the 3-D image spectrum. Next, the dispersion shell is converted to a polar current shell (PCS) using a polar coordinate transformation. After removing outliers along each radial direction of the PCS, a robust sinusoidal curve fitting is applied to the data points along each circumferential direction of the PCS. The angle corresponding to the maximum of the estimated sinusoid function is determined to be the current direction, and the amplitude of this sinusoidal function is the current speed. For validation, the algorithm is tested against both simulated radar images and field data collected by a vertically-polarized X-band system and ground-truthed with measurements from an acoustic Doppler current profiler (ADCP). From the field data, it is observed that when the current speed is less than 0.5 m/s, the root mean square differences between the radar-derived and the ADCP-measured current speed and direction are 7.3 cm/s and 32.7°, respectively. The results indicate that the proposed procedure, unlike most existing current inversion schemes, is not susceptible to high current speeds and circumvents the need to consider aliasing. Meanwhile, the relatively low computational cost makes it an excellent choice in practical marine applications. %0 journal article %@ 0148-0227 %A Xi, H., Larouche, P., Michel, C., Tang, S. %D 2015 %J Journal of Geophysical Research : Oceans %N 5 %P 3286-3300 %R doi:10.1002/2014JC010668 %T Beam attenuation, scattering and backscattering of marine particles in relation to particle size distribution and composition in Hudson Bay (Canada) %U https://doi.org/10.1002/2014JC010668 5 %X This study investigated the relationships between the concentration of biogeochemical parameters and particulate beam attenuation (cp), scattering (bp), and backscattering (bbp) in Hudson Bay. Results showed that most of the variability resulted from the presence of a deep chlorophyll maximum. cp, bp, and bbp were all adequate proxies to estimate total suspended matter (TSM) but were mostly sensitive to particulate inorganic matter (PIM) in the surface layer, and particulate organic matter (POM) at the chlorophyll maximum depth. The backscattering ratio inline image varied in the range of 0.005–0.05 and was inversely related to the POM : TSM ratio. According to the Twardowski et al. (2001) model, the PSD slope ξ well represented inline image and bulk refractive index inline image in relation to particulate composition. For inorganic particulate dominated waters, both inline image and inline image had a larger range and a higher mean value than at organic particulate dominated waters. This knowledge on the optical properties related to the PSD and particulate composition provides valuable information for further investigation and broadens our understanding of ocean optics in high latitude waters leading to potential improvements of regional scale remote sensing algorithms. %0 book part %@ %A Horstmann, J., Nieto Borge, J.C., Seemann, J., Carrasco, R., Lund, B. %D 2015 %J Coastal Ocean Observing Systems %P 281-304 %T Wind, Wave, and Current Retrieval Utilizing X-Band Marine Radars %U %X Since the 1980s, several methodologies have been developed to measure ocean surface wind, waves, and currents using standard marine radars operating at X-band. Today, marine radars are often used operationally to measure the spectral quantities of ocean surface waves. They also have shown to be very useful to measure surface winds and currents as well as bathymetry. Within this chapter, a brief review is given on the most common methods utilized to retrieve wind, currents, and waves. Therefore, a brief introduction on ocean surface backscattering at grazing incidence, as well as the physical basis of the applied methods, is given. Furthermore, the main processing steps of the retrieval methods are introduced and applied to some examples. To show the overall performance of the methodologies, the radar-retrieved parameters are compared to well-accepted measurement techniques. Finally, the limitations of the different radar measurement techniques are discussed. %0 conference lecture %@ %A Maresca, S., Braca, P., Grasso, R., Horstmann, J. %D 2015 %J Oceans 2015 %T The Impact of Sea State on HF Surface-Wave Radar Ship Detection and Tracking Performance %U %X %0 journal article %@ 0148-0227 %A Hordoir, R., Axell, L., Loeptien, U., Dietze, H., Kuznetsov, I. %D 2015 %J Journal of Geophysical Research : Oceans %N 10 %P 6653-6668 %R doi:10.1002/2014JC010642 %T Influence of sea level rise on the dynamics of salt inflows in the Baltic Sea %U https://doi.org/10.1002/2014JC010642 10 %X The Baltic Sea is a marginal sea, located in a highly industrialized region in Central Northern Europe. Saltwater inflows from the North Sea and associated ventilation of the deep exert crucial control on the entire Baltic Sea ecosystem. This study explores the impact of anticipated sea level changes on the dynamics of those inflows. We use a numerical oceanic general circulation model covering both the Baltic and the North Sea. The model successfully retraces the essential ventilation dynamics throughout the period 1961–2007. A suite of idealized experiments suggests that rising sea level is associated with intensified ventilation as saltwater inflows become stronger, longer, and more frequent. Expressed quantitatively as a salinity increase in the deep central Baltic Sea, we find that a sea level rise of 1 m triggers a saltening of more than 1 PSU. This substantial increase in ventilation is the consequence of the increasing cross section in the Danish Straits amplified by a reduction of vertical mixing. %0 journal article %@ 1877-3435 %A Glavovic, B., Limburg, K., Liu, K., Emeis, K., Thomas, H., Kremer, H., Avril, B., Zhang, J., Mulholland, M., Glaser, M., Swaney, D. %D 2015 %J Current Opinion in Environmental Sustainability %P 232-238 %R doi:10.1016/j.cosust.2015.06.003 %T Living on the Margin in the Anthropocene: engagement arenas for sustainability research and action at the ocean–land interface %U https://doi.org/10.1016/j.cosust.2015.06.003 %X The advent of the Anthropocene underscores the need to develop and implement transformative governance strategies that safeguard the Earth's life-support systems, most critically at the ocean–land interface — the Margin. The seaward realm of the Margin is the new frontier for resource exploitation and colonization to meet the needs of coastal nations and humanity overall. Here, we spotlight the pivotal role of the Margin for planetary resilience and sustainability, highlight priority issues, and outline a research strategy which aims to: (a) better understand Margin social-ecological systems; (b) guide sustainable development of Margin resources; (c) design governance regimes to reverse unsustainable practices; (d) facilitate equitable sharing of Margin resources; and (e) evaluate alternative research approaches and partnerships that address major Margin challenges. %0 journal article %@ 0034-4257 %A Brewin, R.J.W., Sathyendranath, S., Mueller, D., Brockmann, C., Deschamps, P.-Y., Devred, E., Doerffer, R., Fomferra, N., Franz, B., Grant, M., Groom, S., Horseman, A., Hu, C., Krasemann, H., Lee, Z.-P., Maritorena, S., Melin, F., Peters, M., Platt, T., Regner, P., Smyth, T., Steinmetz, F., Swinton, J., Werdell, J., White III, G.N. %D 2015 %J Remote Sensing of Environment %P 271-294 %R doi:10.1016/j.rse.2013.09.016 %T The Ocean Colour Climate Change Initiative: III. A round-robin comparison on in-water bio-optical algorithms %U https://doi.org/10.1016/j.rse.2013.09.016 %X Satellite-derived remote-sensing reflectance (Rrs) can be used for mapping biogeochemically relevant variables, such as the chlorophyll concentration and the Inherent Optical Properties (IOPs) of the water, at global scale for use in climate-change studies. Prior to generating such products, suitable algorithms have to be selected that are appropriate for the purpose. Algorithm selection needs to account for both qualitative and quantitative requirements. In this paper we develop an objective methodology designed to rank the quantitative performance of a suite of bio-optical models. The objective classification is applied using the NASA bio-Optical Marine Algorithm Dataset (NOMAD). Using in situRrs as input to the models, the performance of eleven semi-analytical models, as well as five empirical chlorophyll algorithms and an empirical diffuse attenuation coefficient algorithm, is ranked for spectrally-resolved IOPs, chlorophyll concentration and the diffuse attenuation coefficient at 489 nm. The sensitivity of the objective classification and the uncertainty in the ranking are tested using a Monte-Carlo approach (bootstrapping). Results indicate that the performance of the semi-analytical models varies depending on the product and wavelength of interest. For chlorophyll retrieval, empirical algorithms perform better than semi-analytical models, in general. The performance of these empirical models reflects either their immunity to scale errors or instrument noise in Rrs data, or simply that the data used for model parameterisation were not independent of NOMAD. Nonetheless, uncertainty in the classification suggests that the performance of some semi-analytical algorithms at retrieving chlorophyll is comparable with the empirical algorithms. For phytoplankton absorption at 443 nm, some semi-analytical models also perform with similar accuracy to an empirical model. We discuss the potential biases, limitations and uncertainty in the approach, as well as additional qualitative considerations for algorithm selection for climate-change studies. Our classification has the potential to be routinely implemented, such that the performance of emerging algorithms can be compared with existing algorithms as they become available. In the long-term, such an approach will further aid algorithm development for ocean-colour studies. %0 journal article %@ 0739-0572 %A Stanev, E.V., Ziemer, F., Schulz-Stellenfleth, J., Seemann, J., Staneva, J., Gurgel, K. %D 2015 %J Journal of Atmospheric and Oceanic Technology %N 2 %P 256-281 %R doi:10.1175/JTECH-D-13-00164.1 %T Blending Surface Currents from HF Radar Observations and Numerical Modeling: Tidal Hindcasts and Forecasts %U https://doi.org/10.1175/JTECH-D-13-00164.1 2 %X An observation network operating three Wellen Radars (WERAs) in the German Bight, which are part of the Coastal Observing System for Northern and Arctic Seas (COSYNA), is presented in detail. Major consideration is given to expanding the patchy observations over the entire German Bight on a 1-km grid and producing state estimates at intratidal scales, and 6- and 12-h forecasts. This was achieved with the help of the proposed spatiotemporal optimal interpolation (STOI) method, which efficiently uses observations and simulations from a free model run within an analysis window of one or two tidal cycles. In this way the method maximizes the use of available observations and can be considered as a step toward the “best surface current estimate.” The performance of the analysis was investigated based on the achieved reduction of the misfit between model and observations. The complex dynamics of the study domain was illustrated based on the spatial and temporal changes of tidal ellipses for the M2 and M4 constituents from HF radar observations. It was demonstrated that blending observations and numerical modeling facilitates physical interpretation of processes such as the nonlinear distortion of the Kelvin wave in the coastal zone and in particular in front of the Elbe and Weser estuaries. Comparisons with in situ data acquired outside the area covered by the HF radar demonstrated that the analysis method is able to propagate the HF radar information to larger spatial scales. %0 conference lecture %@ %A Assmann, S., Atamanchuk, D., Bittig, H., Bresnahan, P., Brown, P., Carlin, G., Comeau, A., Connelly, D., Downing, B., Fassbender, A., Fiedler, B., Gedela, S., Gkritzalis, T., Hannides, A., Hartman, S., Johnson, K., L’ Esperance, C., Loenborg, C., Loucaides, S., Ma, J., Nair, R., Neill, C., Ntoumas, M., Pereira,E., Poteau, A., Rerolle, V., Rigby, P., Schuster, U., Simpson, K., Spaulding, R., Trull, T., Ulfsbo, A., Voynova, Y. %D 2015 %J 1st International IOCCP Sensors Summer Course – Instrumenting Our Oceans for Better Observations %T A user’s guide for selected autonomous biogeochemical sensors %U %X %0 dataset %@ %A Riethmüller, R. %D 2015 %J PANGAEA %R doi:10.1594/PANGAEA.848835 %T Station list and links to master tracks in different resolutions of HEINCKE cruise HE445, Bremerhaven - Bremerhaven, 2015-05-19 to 2015-05-31 %U https://doi.org/10.1594/PANGAEA.848835 %X %0 dataset %@ %A Riethmüller, R. %D 2015 %J PANGAEA %R doi:10.1594/PANGAEA.845234 %T Station list and links to master tracks in different resolutions of HEINCKE cruise HE371, Bremerhaven - Bremerhaven, 2012-02-13 to 2012-02-24 %U https://doi.org/10.1594/PANGAEA.845234 %X %0 journal article %@ 0148-0227 %A Ott, L., Pawson, S., Collatz, J., gregg, W., Menemenlis, D., Brix, H., Rousseaux, C., Bowman, K., liu, J., Eldering, A., Gunson, M., Kawa, S.R. %D 2015 %J Journal of Geophysical Research : Atmospheres %N 2 %P 734-765 %R doi:10.1002/2014JD022411 %T Assessing the magnitude of CO2 flux uncertainty in atmospheric CO2 records using products from NASA's Carbon Monitoring Flux Pilot Project %U https://doi.org/10.1002/2014JD022411 2 %X NASA's Carbon Monitoring System (CMS) Flux Pilot Project (FPP) was designed to better understand contemporary carbon fluxes by bringing together state-of-the art models with remote sensing datasets. Here we report on simulations using NASA's Goddard Earth Observing System Model, version 5 (GEOS-5) which was used to evaluate the consistency of two different sets of observationally informed land and ocean fluxes with atmospheric CO2 records. Despite the observation inputs, the average difference in annual terrestrial biosphere flux between the two land (NASA Ames CASA and CASA-GFED) models is 1.7 Pg C for 2009-2010. Ocean models (NOBM and ECCO2-Darwin) differ by 35% in their global estimates of carbon flux with particularly strong disagreement in high latitudes. Based upon combinations of terrestrial and ocean fluxes, GEOS-5 reasonably simulated the seasonal cycle observed at northern hemisphere surface sites and by the Greenhouse gases Observing SATellite (GOSAT) while the model struggled to simulate the seasonal cycle at southern hemisphere surface locations. Though GEOS-5 was able to reasonably reproduce the patterns of XCO2 observed by GOSAT, it struggled to reproduce these aspects of AIRS observations. Despite large differences between land and ocean flux estimates, resulting differences in atmospheric mixing ratio were small, typically less than 5 ppm at the surface and 3 ppm in the XCO2 column. A statistical analysis based on the variability of observations shows that flux differences of these magnitudes are difficult to distinguish from inherent measurement variability, regardless of the measurement platform. %0 journal article %@ 0022-3670 %A Hieronymus, M., Nycander, J. %D 2015 %J Journal of Physical Oceanography %N 7 %P 1843-1857 %R doi:10.1175/JPO-D-14-0174.1 %T Finding the Minimum Potential Energy State by Adiabatic Parcel Rearrangements with a Nonlinear Equation of State: An Exact Solution in Polynomial Time %U https://doi.org/10.1175/JPO-D-14-0174.1 7 %X The problem of finding the state of minimum potential energy through the rearrangement of water parcels with a nonlinear equation of state is discussed in the context of a combinatorial optimization problem. It is found that the problem is identical to a classical optimization problem called the linear assignment problem. This problem belongs to a problem class known as P, a class of problems that have known efficient solutions. This is very fortunate since this study’s problem has been suggested to be an asymmetric traveling salesman problem. A problem that belongs to a class called NP-hard, for which no efficient solutions are known. The difference between the linear assignment problem and the traveling salesman problem is discussed and made clear by looking at the different constraints used for the two problems. It is also shown how the rearrangement of water parcels that minimizes the potential energy can be found in polynomial time using the so-called Hungarian algorithm. The Hungarian algorithm is then applied to a simplified ocean stratification, and the result is compared to a few different approximate solutions to the minimization problem. It is found that the improved accuracy over the approximate methods comes at a high computational cost. Last, the algorithm is applied to a realistic ocean stratification using a technique that splits the minimization problem into smaller bits. %0 journal article %@ 0094-8276 %A Nycander, J., Hieronymus, M., Roquet, F. %D 2015 %J Geophysical Research Letters %N 18 %P 7714-7721 %R doi:10.1002/2015GL065525 %T The nonlinear equation of state of sea water and the global water mass distribution %U https://doi.org/10.1002/2015GL065525 18 %X The role of nonlinearities of the equation of state (EOS) of seawater for the distribution of water masses in the global ocean is examined through simulations with an ocean general circulation model with various manipulated versions of the EOS. A simulation with a strongly simplified EOS, which contains only two nonlinear terms, still produces a realistic water mass distribution, demonstrating that these two nonlinearities are indeed the essential ones. Further simulations show that each of these two nonlinear terms affects a specific aspect of the water mass distribution: the cabbeling term is crucial for the formation of Antarctic Intermediate Water and the thermobaric term for the layering of North Atlantic Deep Water and Antarctic Bottom Water. %0 journal article %@ 0278-4343 %A Mielck, F., Holler, P., Bürk, D., Hass, H.C. %D 2015 %J Continental Shelf Research %N Part A %P 31-41 %R doi:10.1016/j.csr.2015.10.016 %T Interannual variability of sorted bedforms in the coastal German Bight (SE North Sea) %U https://doi.org/10.1016/j.csr.2015.10.016 Part A %X Sorted bedforms are ubiquitous on the inner continental shelves worldwide. They are described as spatially-grain-size-sorted features consisting of small rippled medium-to-coarse sand and can remain stable for decades. However, the knowledge about their genesis and development is still fragmentary. For this study, a representative investigation area (water depth<15 m) located on the shelf west of the island of Sylt (SE North Sea, Germany) was periodically surveyed with hydroacoustic means (i.e. sidescan sonar, multibeam echo sounder, and sub-bottom profiler) during 2010–2014. Since this area is influenced by tidal and wind-driven currents, the aim was to detect and examine interannual variabilities in the characteristics of the prevailing sorted bedforms. Our measurements reveal sinuous stripes of rippled medium sand which are embedded in shallow symmetrical depressions. These domains are surrounded by relatively smooth fine-sand areas. These sorted bedforms were identified as flow-transverse features that are maintained by ebb and flood currents of almost equal strengths that flow in opposite directions. This bidirectional flow field generates sharp boundaries between the medium- and fine-sand domains in both current directions. Further to the north, where flood currents are dominant, asymmetric sorted bedforms were detected which show sharp boundaries only in flood-current direction. Comparisons between the measurements of the different years show no significant variations in morphology and distribution of the sorted bedforms. However, variations of the boundaries between the medium and the fine-sand domains were observed. Additionally, new minor sorted bedforms and rippled excavation marks as well as new fine-sand areas developed and disappeared occasionally. It can be supposed that such sediment winnowing and focusing processes take place during periodically recurring storm surges, which change the shapes of the features. Moreover, variations in alignments and sizes of the small ripple formations were detected. They seem to indicate the directions and intensities of previous storm events. %0 dataset %@ %A Carrasco, R., Horstmann, J. %D 2015 %J PANGAEA %R doi:10.1594/PANGAEA.874511 %T German Bight surface drifter data from Heincke cruise HE 445 %U https://doi.org/10.1594/PANGAEA.874511 %X The drifters were deployed within the German Bight of the North Sea from the FS Heincke during cruise HE 445, which was performed between 18. May and 1. June 2015. The utilized drifters obtain their position via the Global Positioning System (GPS) and communicated their locations to the lab via Iridium (a global full ocean coverage bidirectional satellite communication network). Within the experiment, two different drifter models were used. The first drifter model used for courses 1 to 6 is a cylinder shaped drifter (MD03i), which has a diameter of 0.1 m and a length of 0.32 m, where only approx. 0.08 m are above the water surface when deployed). The other drifters for courses 7 to 9 were sphere shaped (ODi) with a 0.2 m diameter, which is only approx. 0.1 m above the water surface. To enhance the drag of both types of drifters, a sail was attached 0.5 m bellow the sea surface with a 0.5m length and diameter. Due to the very small sail area above the water surface the drifter's path, represent the current in the upper meter of the water column. Project: PACES II (Polar Regions and Coasts in a Changing Earth System). %0 journal article %@ 0924-7963 %A Emeis, K., van Beusekom, J., Callies, U., Ebinghaus, R., Kannen, A., Kraus, G., Kröncke, I., Lenhatz, H., Lorkoswski, I., Matthias, V., Möllmann, H., Pätsch, J., Scharfe, M., Thomas, H., Weisse, R., Zorita, E. %D 2015 %J Journal of Marine Systems %P 18-33 %R doi:10.1016/j.jmarsys.2014.03.012 %T The North Sea - A shelf sea in the Anthropocene %U https://doi.org/10.1016/j.jmarsys.2014.03.012 %X Global and regional change clearly affects the structure and functioning of ecosystems in shelf seas. However, complex interactions within the shelf seas hinder the identification and unambiguous attribution of observed changes to drivers. These include variability in the climate system, in ocean dynamics, in biogeochemistry, and in shelf sea resource exploitation in the widest sense by societies. Observational time series are commonly too short, and resolution, integration time, and complexity of models are often insufficient to unravel natural variability from anthropogenic perturbation. The North Sea is a shelf sea of the North Atlantic and is impacted by virtually all global and regional developments. Natural variability (from interannual to multidecadal time scales) as response to forcing in the North Atlantic is overlain by global trends (sea level, temperature, acidification) and alternating phases of direct human impacts and attempts to remedy those. Human intervention started some 1000 years ago (diking and associated loss of wetlands), expanded to near-coastal parts in the industrial revolution of the mid-19th century (river management, waste disposal in rivers), and greatly accelerated in the mid-1950s (eutrophication, pollution, fisheries). The North Sea is now a heavily regulated shelf sea, yet societal goals (good environmental status versus increased uses), demands for benefits and policies diverge increasingly. Likely, the southern North Sea will be re-zoned as riparian countries dedicate increasing sea space for offshore wind energy generation — with uncertain consequences for the system's environmental status. We review available observational and model data (predominantly from the southeastern North Sea region) to identify and describe effects of natural variability, of secular changes, and of human impacts on the North Sea ecosystem, and outline developments in the next decades in response to environmental legislation, and in response to increased use of shelf sea space. %0 dataset %@ %A Riethmüller, R. %D 2015 %J PANGAEA %R doi:10.1594/PANGAEA.843663 %T Station list and links to master tracks in different resolutions of HEINCKE cruise HE331, Bremerhaven - Bremerhaven, 2010-07-13 to 2010-07-20 %U https://doi.org/10.1594/PANGAEA.843663 %X %0 conference poster %@ %A Hieronymi, M. %D 2015 %J SOLAS Open Science Conference 2015 %T Solar radiative transfer across the dynamic air-sea interface %U %X %0 conference poster %@ %A Hieronymi, M., Mueller, D., Krasemann, H., Schoenfeld, W., Roettgers, R., Doerffer, R. %D 2015 %J Sentinel-3 for Science Workshop %T Regional ocean colour remote sensing algorithm for the Baltic Sea %U %X %0 conference paper %@ %A Petihakis, G., Petersen, W., Nair, R., Faimali, M., Pavanello, G., Boukerma, K., Delauney, L., Puillat, I., Farcy, P., Greenwood, N. %D 2015 %J Conference Publications, OCEANS 2015 - MTS/IEEE Washington %P 1-8 %R doi:10.23919/OCEANS.2015.7404554 %T Harmonization in the Joint European Research Infrastructure Network for Coastal Observatories - JERICO %U https://doi.org/10.23919/OCEANS.2015.7404554 %X The JERICO European research infrastructure (RI) is integrating diverse platform types such as fixed buoys, piles, moorings, drifters, FerryBoxes, gliders, HF radars, coastal cable observatories and the associated technologies dedicated to observe and monitor coastal European seas. The first steps of setting up, coordination and harmonization were done during 2011 to 2015 in the framework of FP7-JERICO (www.jericofp7.eu), a 4-year long infrastructure project co-funded by the European Commission with 27 partners from 17 European countries under the coordination of IFREMER. Next steps are driven in the H2020-JERICO-NEXT European project until 2019, involving 33 partners. The main objective of the JERICO consortium is to establish a Pan European approach for a European coastal marine observatory network. This is a dynamic activity going beyond a project's lifetime including continuous efforts towards harmonization in terms of design, operation, and maintenance, the evolution and extension of the current systems as well as the delivery of data and products to the users. Our scope here is to present the work done towards the harmonization of operation and maintenance methods, in FP7JERICO and the next steps in JERICO-NEXT. As a starting point of harmonization assessment, the priority was given to the most pressing issues like calibration and biofouling, while it is the first time that a Best Practice report on all phases of the system from first installation to operation and maintenance is attempted adopting a platform based approach. %0 conference poster %@ %A Hieronymi, M. %D 2015 %J 6th CCI – Collocation Meeting %T Ocean Colour at Low Sun and High Waves %U %X %0 conference paper %@ %A Hieronymi, M., Mueller, D., Krasemann, H., Schoenfeld, W., Roettgers, R., Doerffer, R. %D 2015 %J Proceedings of Sentinel-3 for Science Workshop %P 23 %T Regional ocean colour remote sensing algorithm for the Baltic Sea %U %X The Baltic Sea is a challenging study site from an optically point of view. Its partly highly absorbing waters are mainly associated with the presence of coloured dissolved organic matter and often accompanied by non-algae absorbing particles. In addition, the Baltic Sea area is characterised by massive annual surface blooms of cyanobacteria. In Europe, the Baltic Sea is a very specific and important case study with intense user interest. In the framework of different research projects as the “Ocean Colour Climate Change Initiative”, the “SEOM OC Extreme Case 2 Waters”, and partly “MyOcean”, we aim to develop an optimised, error-characterised, regional ocean colour processor applicable to several satellite sensors, like MODIS, MERIS, VIIRS, and OLCI. The procedure, which is used to determine inherent optical properties and different water constituents’ concentrations from remote sensing reflectance, is an artificial Neural Network (NN). We provide first results of comparisons of in-situ data with different ocean colour products. %0 conference poster %@ %A Hieronymi, M. %D 2015 %J Sentinel-3 for Science Workshop %T Ocean Colour at Low Sun and High Waves %U %X %0 conference poster %@ %A Hieronymi, M. %D 2015 %J Proceedings of Sentinel-3 for Science Workshop %P 71 %T Ocean Colour at Low Sun and High Waves %U %X Many space-borne sensors are deployed to image the ocean in the visible portion of the spectrum. The colour of the sea, or more precisely the spectral water-leaving radiance, gives us information about the concentration of water constituents, e.g., chlorophyll, coloured dissolved organic matter, or suspended mineral matter. The bidirectional nature of the upwelling radiance just beneath the water surface and the interaction of this radiance with the air- sea interface depend on the viewing- and sun-geometry and surface waves. If we consider wave elevation and wave shadowing effects, perceptible deviations of the transmittance and reflectance of the air-water interface occur at low Sun (zenith angle of more than 60°) in comparison with wind-depending wave slope statistics. The inclusion of appropriate wind and wave data, i.e., wave heights and periods, can help to reduce uncertainties related to the Fresnel-reflecting ocean surface - in particular for large solar zenith angles. This especially regards remote sensing of ocean colour at high latitudes and atmospheric correction. %0 journal article %@ 0874-0380 %A Borges, L.M.S., Costa, F.O. %D 2014 %J Acoreana %P 109-116 %T New Records of Marine Wood Borers (Bivalvia: Teredinidae and Isopoda: Limnoriidae) from Sao Miguel, Azores - With A Discussion of some Aspects of their Biogeography %U %X sugere uma recente expansão com origem no Sul da Europa. %0 journal article %@ 0022-0981 %A Wollschlaeger, J., Roettgers, R., Petersen, W., Wiltshire, K.H. %D 2014 %J Journal of Experimental Marine Biology and Ecology %P 138-147 %R doi:10.1016/j.jembe.2014.01.011 %T Performance of absorption coefficient measurements for the in situ determination of chlorophyll-a and total suspended matter %U https://doi.org/10.1016/j.jembe.2014.01.011 %X Absorption measurements turned out to be promising optical proxies for determining [TSM] and [chl-a] due to their lower variability compared with the other proxies. This improved accuracy could be already partially achieved also for continuous measurements. Moreover, a combination of the different optical methods has the potential to provide additional information besides concentration, such as the source of TSM in the water or physiological condition of the phytoplankton. %0 journal article %@ 0924-7963 %A Liu, F., Su, J., Moll, A., Krasemann, H., Chen, X., Pohlmann, T., Wirtz, K. %D 2014 %J Journal of Marine Systems %P 303-317 %R doi:10.1016/j.jmarsys.2013.07.007 %T Assessment of the summer-autumn bloom in the Bohai Sea using satellite images to identify the roles of wind mixing and light conditions %U https://doi.org/10.1016/j.jmarsys.2013.07.007 %X In shallow coastal ecosystems, summer–autumn phytoplankton blooms require thorough investigation because of their large variability in space and time. This variability results primarily from the complex interplay of different governing factors, e.g., wind mixing and light availability. To identify the effects of these governing factors on the summer–autumn blooms in the Bohai Sea, we first established a statistical approach to define the biological variables that characterize summer–autumn blooms, i.e., the bloom onset time (denoted as bloom onset), the bloom magnitude, and the chlorophyll-a (Chl-a) increase rate during the bloom period (denoted as Chl-a increase rate). These variables were quantified using daily Medium Resolution Imaging Spectrometer (MERIS) satellite scenes from 2003 to 2009. We observed a remarkable onshore–offshore gradient in all three biological variables. For example, bloom onsets were delayed in coastal areas compared to deep offshore waters. Spatially, the bloom onset exhibited a high correlation with wind mixing prior to the bloom period (R > 0.6), whereas the Chl-a increase rate and bloom magnitude were highly correlated to the distribution of the light attenuation coefficient (Kd(min), R = − 0.65 and R = 0.69, respectively). Furthermore, the empirical orthogonal function (EOF) analysis revealed similar interannual variability in the Kd(min), bloom onset and Chl-a increase rate. We also observed similar interannual trends in the bloom magnitude and wind mixing during the bloom period. From the analysis above, we believe that light is a crucial limiting factor for summer–autumn phytoplankton dynamics in the Bohai Sea. Wind influenced Chl-a dynamics in many ways and at various scales. Spatially, weak wind speeds prior to bloom events tended to provide favorable light conditions for the development of blooms. Over the long-term, however, enhanced wind mixing tended to supply the surface layer with nutrients more effectively and thus promoted a higher bloom intensity. %0 conference lecture %@ %A Horstmann, J., Falchetti, S., Wackermann, C., Caruso, M., Graber, H. %D 2014 %J 35th Canadian Symposium on Remote Sensing and IGARSS 2014 %T Wind retrieval at C-band Cross Polarization %U %X %0 conference lecture %@ %A Maresca, S., Braca, P., Horstmann, J., Grasso, R. %D 2014 %J 17th International Conference on Information Fusion, Fusion 2014 %T Multiple Oceanographic HF Surface-Wave Radars Applied to Maritime Surveillance %U %X %0 conference lecture %@ %A Merckelbach, L., Riethmueller, R. %D 2014 %J European Geosciences Union General Assembly, EGU 2014 %T Vertical suspended sediment uxes observed from a formation of underwater gliders %U %X %0 conference lecture %@ %A Wollschlaeger, J., Voss, D., Zielinski, O., Petersen, W. %D 2014 %J Sensor Systems for a Changing Ocean, SSCO 2014, Workshop %T Continuous observations of biological and environmental parameters by optical absorption and fluorescence – special focus on an integrating cavity approach %U %X %0 journal article %@ 2242-1300 %A Borges, L.M.S., Sivrikaya, H., Cragg, S.M. %D 2014 %J BioInvasions Records %N 1 %P 25-28 %R doi:10.3391/bir.2014.3.1.04 %T First records of the warm water shipworm Teredo bartschi (Bivalvia, Teredinidae) in Mersin, southern Turkey and in Olhao, Portugal %U https://doi.org/10.3391/bir.2014.3.1.04 1 %X Bivalves of the family Teredinidae are among the most destructive wood-boring species in the sea. We report the first occurrences of the warm-water shipworm Teredo bartschi in Mersin, Turkey, and Olhão, Portugal. The colonisation of the site in Mersin is likely to have occurred by rafting adults originating from the Red Sea, which passed through the Suez Canal (lessepsian migrants). T. bartschi might have been introduced in Olhão Harbour, Portugal, either by rafting adults with larvae transported by currents or by larvae transported by ships in ballast water. These seem to be the first published records of established T. bartschi populations in the Mediterranean and in northeast Atlantic. %0 conference lecture %@ %A Maresca, S., Braca, P., Horstmann, J., Grasso, R. %D 2014 %J 2014 IEEE International Conference on Acoustics, Speech and Signal Processing, ICASSP 2014 %T A Network of HF Surface wave Radars for Maritime Surveillance: Preliminary Results in the German Bight %U %X %0 journal article %@ 0142-7873 %A Wollschlaeger, J., Nicolaus, A., Wiltshire, K., Metfies, K. %D 2014 %J Journal of Plankton Research %N 3 %P 695-708 %R doi:10.1093/plankt/fbu003 %T Assessment of North Sea phytoplankton via molecular sensing - A method evaluation %U https://doi.org/10.1093/plankt/fbu003 3 %X Phytoplankton community analysis is important with respect to natural or human-induced changes in the marine environment. Because of the efforts involved and the limitations of traditional methods, molecular sensing approaches are becoming more popular. Among others, microarray techniques targeting ribosomal 18S sequences have been successfully applied for phytoplankton investigation. In this contribution, we compared the results of two microarray methods targeting 18S rDNA and 18S rRNA with the results obtained from microscopy, HPLC and flow cytometry. On a qualitative basis, the microarrays showed similar or potentially better performance than the non-molecular methods. Quantitatively, our data suggest that microarray signals obtained from 18S rDNA provide relatively rough estimates of phytoplankton abundance. In contrast, when targeting 18S rRNA instead, a robust linear relationship (r² = 0.68) between molecular sensing signal and microscopic cell counts could be demonstrated using a probe specific to the genus Pseudo-nitzschia as an example. Thus, for both qualitative and quantitative purposes, microarray techniques can be valuable additions to traditional methods for phytoplankton analysis. Routine monitoring approaches in particular could benefit from advantages like reduced effort, higher taxonomic resolution and a potential for automation. %0 conference lecture %@ %A Maresca, S., Braca, P., Horstmann, J., Grasso, R. %D 2014 %J Ocean Radar Conference for Asia-Pacific %T Maritime Surveillance with HF Surface-Wave Radars: Preliminary Experimental Results from the German Bight %U %X %0 conference lecture %@ %A Maresca, S., Braca, P., Horstmann, J., Grasso, R. %D 2014 %J OCEANS 2014 %T Oceanographic HF Surface-Wave Radars for Maritime Surveillance in the German Bight %U %X %0 conference lecture %@ %A Horstmann, J., Falchetti, S., Wackerman, C., Caruso, M., Graber, H. %D 2014 %J OCEANS 2014 %T Typhoon winds retrieved from Synthetic Aperture Radar DATA %U %X %0 journal article %@ 0094-8276 %A Sommer, T., Carpenter, J.R., Wuest, A. %D 2014 %J Geophysical Research Letters %N 14 %P 5114-5121 %R doi:10.1002/2014GL060716 %T Double-diffusive interfaces in Lake Kivu reproduced by direct numerical simulations %U https://doi.org/10.1002/2014GL060716 14 %X used heat flux parameterization underestimates the total fluxes by a factor of 1.3 to 2.2. %0 journal article %@ 1385-1101 %A Nauw, J.J., Merckelbach, L.M., Ridderinkhof, H., Aken, H.M.van %D 2014 %J Journal of Sea Research %P 17-29 %R doi:10.1016/j.seares.2013.11.013 %T Long-term ferry-based observations of the suspended sediment fluxes through the Marsdiep inlet using acoustic Doppler current profilers %U https://doi.org/10.1016/j.seares.2013.11.013 %X Long-term measurements with a hull mounted acoustic Doppler current profiler (ADCP) under the ferry, crossing the Marsdiep inlet between the mainland and the island of Texel (the Netherlands), were used to determine the volume flux and the flux of suspended particulate matter (SPM) through this inlet for the period 2003–2005. Profiles of the SPM concentration were estimated from profiles of the acoustic backscatter intensity in which the shift between the low and the high turbulent regime is taken into account. Calibration constants and tuning parameters were estimated by using data collected during 7 different 13 hour anchor stations. The residual (water) volume flux through the inlet appears to vary strongly on a variety of time scales from daily to inter-annual. A regression analysis indicates that the daily residual volume transport correlates well with the daily mean wind component from the south; the latter likely drives the residual flow along the coast of Holland. The observed residual SPM transport of 7 to 11 Mton/yr is dominated by the correlation between tidal velocity and SPM concentration variations. This leads to an import as currents and SPM concentrations during flood were higher than those during ebb, a process generally known as tidal asymmetry. Our analysis has shown that regular observations with a ferry mounted ADCP is an effective method to monitor the volume and SPM transport processes in an estuary. %0 conference lecture %@ %A Carpenter, J., Timmermans, M.-L., Sommer, T., Wuest, A. %D 2014 %J Ocean Sciences Meeting 2014 %T New insights into heat fluxes through double-diffusive staircases %U %X %0 journal article %@ 1387-3547 %A Shipway, J.R., Borges, L.M.S., Mueller, J., Cragg, S.M. %D 2014 %J Biological Invasions %N 10 %P 2037-2048 %R doi:10.1007/s10530-014-0646-9 %T The broadcast spawning Caribbean shipworm, Teredothyra dominicensis (Bivalvia, Teredinidae), has invaded and become established in the eastern Mediterranean Sea %U https://doi.org/10.1007/s10530-014-0646-9 10 %X Teredinids, commonly referred to as shipworms, are wood-boring bivalves estimated to cause over one billion dollars’ worth of damage to submerged wooden structures per annum. This paper reports the detection and establishment of the Caribbean shipworm Teredothyra dominicensis (Bivalvia, Teredinidae) in the eastern Mediterranean Sea. Identification was confirmed using an integrative taxonomical approach combining morphology, morphometry and molecular markers (COI-5P and 18S), thus improving both the taxonomic resolution and tractability of this invasive species. Sequence comparisons between indigenous Caribbean and Mediterranean specimens were at least 99 % identical. Wooden panels placed at the site of discovery were infested exclusively by T. dominicensis with specimens of varying size and age, indicating multiple settlement events and the presence of breeding populations in the region. Anatomical and behavioural observations confirm the species as a broadcast spawner with larvae undergoing planktotrophic development, thus distribution range is potentially extensive. Of the possible introduction vectors, transport via ballast water is proposed as the most likely. The establishment of breeding populations of a tropical teredinid in the Mediterranean is of considerable concern as tropical species are particularly destructive and degrade wood more rapidly than the species currently found in the region. This threat is likely to increase in severity due to global warming, as increases in temperature and salinity may lead to an increase in the distribution range, development rate and boring activity of teredinids. %0 journal article %@ 1742-9994 %A Borges, L.M.S., Merckelbach, L.M., Sampaio, I., Cragg, S.M. %D 2014 %J Frontiers in Zoology %P 13 %R doi:10.1186/1742-9994-11-13 %T Diversity, environmental requirements, and biogeography of bivalve wood-borers (Teredinidae) in European coastal waters %U https://doi.org/10.1186/1742-9994-11-13 %X A total of nine teredinid species were found established in European coastal waters. Seven were considered cryptogenic, of unknown origin, and two were considered alien species. Teredo navalis and Nototeredo norvagica were the species with the widest distribution in European waters. Recently, T. navalis has been reported occurring further east in the Baltic Sea but it was not found at a number of sites on the Atlantic coast of southern Europe. The Atlantic lineage of Lyrodus pedicellatus was the dominant teredinid in the southern Atlantic coast of Europe. In the Mediterranean six teredinid species occurred in sympatry, whereas only three of these occurred in the Black Sea. The species that pose the greatest hazard to wooden maritime structures in European coastal areas are T. navalis and the two lineages of L. pedicellatus. %0 journal article %@ 1994-0416 %A Haller, M., Brümmer, B., Müller, G. %D 2014 %J The Cryosphere %N 1 %P 275-288 %R doi:10.5194/tc-8-275-2014 %T Atmosphere–ice forcing in the transpolar drift stream: results from the DAMOCLES ice-buoy campaigns 2007–2009 %U https://doi.org/10.5194/tc-8-275-2014 1 %X During the EU research project Developing Arctic Modelling and Observing Capabilities for Long-term Environmental Studies (DAMOCLES), 18 ice buoys were deployed in the region of the Arctic transpolar drift (TPD). Sixteen of them formed a quadratic grid with 400 km side length. The measurements lasted from 2007 to 2009. The properties of the TPD and the impact of synoptic weather systems on the ice drift are analysed. Within the TPD, the speed increases by a factor of almost three from the North Pole to the Fram Strait region. The hourly buoy position fixes would show that the speed is underestimated by 10–20% if positions were taken at only 1–3 day intervals as it is usually done for satellite drift estimates. The geostrophic wind factor Ui / Ug (i.e. the ratio of ice speed Ui and geostrophic wind speed Ug), in the TPD amounts to 0.012 on average, but with regional and seasonal differences. The constant Ui / Ug relation breaks down for Ug < 5 m s−1. The impact of synoptic weather systems is studied applying a composite method. Cyclones (anticyclones) cause cyclonic (anticyclonic) vorticity and divergence (convergence) of the ice drift. The amplitudes are twice as large for cyclones as for anticyclones. The divergence caused by cyclones corresponds to a 0.1–0.5% per 6 h open water area increase based on the composite averages, but reached almost 4% within one day during a strong August 2007 storm. This storm also caused a long-lasting (over several weeks) rise of Ui and Ui / Ug and changed the ice conditions in a way which allowed large amplitudes of inertial ice motion. The consequences of an increasing Arctic storm activity for the ice cover are discussed. %0 journal article %@ 2211-1220 %A Frank, C., Meier, D., Voss, D., Zielinski, O. %D 2014 %J Methods in Oceanography %P 34-43 %R doi:10.1016/j.mio.2014.09.002 %T Computation of nitrate concentrations in coastal waters using an in situ ultraviolet spectrophotometer: Behavior of different computation methods in a case study a steep salinity gradient in the southern North Sea %U https://doi.org/10.1016/j.mio.2014.09.002 %X An extensive dataset of a transect from the Southern North Sea into the Weser estuary (RV HEINCKE transect 345), which covers a broad salinity range as well as a broad range of nitrate concentrations, is used to exemplary show the potential and the limitations of all three methods under these conditions. %0 conference paper %@ %A Maresca, S., Braca, P., Horstmann, J., Grasso, R. %D 2014 %J Conference Publications, Information Fusion (FUSION), 2014 17th International Conference on Information Fusion, Fusion 2014 %P 1-8 %T Multiple Oceanographic HF Surface-Wave Radars Applied to Maritime Surveillance %U %X In the context of maritime surveillance, low-power high-frequency surface-wave (HFSW) radars are attracting significant attention as cost-effective tools for long-range ship detection and tracking applications. In this paper, multi-target tracking and data fusion techniques are applied to live-recorded data from a network of three oceanographic HFSW radars installed on the coast of the German Bight, in the North Sea. This campaign follows a previous one conducted in 2009, in which two HFSW radars were deployed on the coast of the Ligurian Sea, in the Mediterranean. Ship reports from the automatic identification system, recorded from a number of coastal stations, are exploited as ground truth information. A methodology is then applied to classify the fused tracks and to estimate single-sensor and data fusion performances. Both in situ and model data are used to investigate the capabilities of the systems according to the variations of the meteorological and oceanographic conditions. Finally, preliminary results are presented and discussed, together with outlines for future works. %0 journal article %@ 0280-6509 %A Liu, J., Bowman, K.W., Lee, M., Henze, D.K., Bousserez, N., Brix, H., Collatz, G.J., Menemenlis, D., Ott, L., Pawson, S., Jones, D., Nassar, R. %D 2014 %J Tellus B %P 22486 %R doi:10.3402/tellusb.v66.22486 %T Carbon monitoring system flux estimation and attribution: impact of ACOS-GOSAT XCO2 sampling on the inference of terrestrial biospheric sources and sinks %U https://doi.org/10.3402/tellusb.v66.22486 %X Using an Observing System Simulation Experiment (OSSE), we investigate the impact of JAXA Greenhouse gases Observing SATellite ‘IBUKI’ (GOSAT) sampling on the estimation of terrestrial biospheric flux with the NASA Carbon Monitoring System Flux (CMS-Flux) estimation and attribution strategy. The simulated observations in the OSSE use the actual column carbon dioxide (XCO2) b2.9 retrieval sensitivity and quality control for the year 2010 processed through the Atmospheric CO2 Observations from Space algorithm. CMS-Flux is a variational inversion system that uses the GEOS-Chem forward and adjoint model forced by a suite of observationally constrained fluxes from ocean, land and anthropogenic models. We investigate the impact of GOSAT sampling on flux estimation in two aspects: 1) random error uncertainty reduction and 2) the global and regional bias in posterior flux resulted from the spatiotemporally biased GOSAT sampling. Based on Monte Carlo calculations, we find that global average flux uncertainty reduction ranges from 25% in September to 60% in July. When aggregated to the 11 land regions designated by the phase 3 of the Atmospheric Tracer Transport Model Intercomparison Project, the annual mean uncertainty reduction ranges from 10% over North American boreal to 38% over South American temperate, which is driven by observational coverage and the magnitude of prior flux uncertainty. The uncertainty reduction over the South American tropical region is 30%, even with sparse observation coverage. We show that this reduction results from the large prior flux uncertainty and the impact of non-local observations. Given the assumed prior error statistics, the degree of freedom for signal is ~1132 for 1-yr of the 74 055 GOSAT XCO2 observations, which indicates that GOSAT provides ~1132 independent pieces of information about surface fluxes. We quantify the impact of GOSAT’s spatiotemporally sampling on the posterior flux, and find that a 0.7 gigatons of carbon bias in the global annual posterior flux resulted from the seasonally and diurnally biased sampling when using a diagonal prior flux error covariance. %0 journal article %@ 1932-6203 %A Borges, L.M., Merckelbach, L.M., Cragg, S.M. %D 2014 %J PLoS One %N 10 %P 109593 %R doi:10.1371/journal.pone.0109593 %T Biogeography of Wood-Boring Crustaceans (Isopoda: Limnoriidae) Established in European Coastal Waters %U https://doi.org/10.1371/journal.pone.0109593 10 %X Marine wood-borers of the Limnoriidae cause great destruction to wooden structures exposed in the marine environment. In this study we collated occurrence data obtained from field surveys, spanning over a period of 10 years, and from an extensive literature review. We aimed to determine which wood-boring limnoriid species are established in European coastal waters; to map their past and recent distribution in Europe in order to infer species range extension or contraction; to determine species environmental requirements using climatic envelopes. Of the six species of wood-boring Limnoria previously reported occurring in Europe, only Limnoria lignorum, L. quadripunctata and L. tripunctata are established in European coastal waters. L. carinata and L. tuberculata have uncertain established status, whereas L. borealis is not established in European waters. The species with the widest distribution in Europe is Limnoria lignorum, which is also the most tolerant species to a range of salinities. L. quadripunctata and L. tripunctata appear to be stenohaline. However, the present study shows that both L. quadripunctata and L. tripunctata are more widespread in Europe than previous reports suggested. Both species have been found occurring in Europe since they were described, and their increased distribution is probably the results of a range expansion. On the other hand L. lignorum appears to be retreating poleward with ocean warming. In certain areas (e.g. southern England, and southern Portugal), limnoriids appear to be very abundant and their activity is rivalling that of teredinids. Therefore, it is important to monitor the distribution and destructive activity of these organisms in Europe. %0 conference paper %@ %A Maresca, S., Braca, P., Horstmann, J., Grasso, R. %D 2014 %J Acoustics, Speech and Signal Processing, Proceedings of 2014 IEEE International Conference on Acoustics, Speech and Signal Processing, ICASSP 2014 %P 6077-6081 %R doi:10.1109/ICASSP.2014.6854771 %T A Network of HF Surface wave Radars for Maritime Surveillance: Preliminary Results in the German Bight %U https://doi.org/10.1109/ICASSP.2014.6854771 %X In the context of maritime surveillance, low-power HF surface-wave (HFSW) radars have demonstrated to be a cost-effective long-range early-warning sensor for ship detection and tracking. In this work, multi-target tracking and data fusion techniques are applied to live-recorded data from a network of oceanographic HFSW radars installed in the German Bight (North Sea). This experimentation closely follows the one conducted in the Ligurian Sea (Mediterranean Sea) by NATO Science and Technology Organization (STO) Centre for Maritime Research and Experimentation (CMRE) during the Battlespace Preparation 2009 (BP09) campaign. Ship reports from the Automatic Identification System (AIS), recorded from both coastal and satellite-based stations, are exploited as ground truth information and a methodology is applied to classify the fused tracks and to estimate system performances. Preliminary results are presented and discussed, together with an outline for future works. %0 journal article %@ 0143-1161 %A Karimova, S. %D 2014 %J International Journal of Remote Sensing %N 16 %P 6113-6134 %R doi:10.1080/01431161.2014.943327 %T Hydrological fronts seen in visible and infrared MODIS imagery of the Black Sea %U https://doi.org/10.1080/01431161.2014.943327 16 %X This article presents an examination of hydrological fronts in the Black Sea based on visible and infrared Aqua Moderate Resolution Imaging Spectrometer (MODIS) imagery obtained during 2008–2013. First the images were preliminarily treated (e.g. via applying a median filter) and then the fronts were detected using the Sobel operator. Further processing of the fields of the gradient norm thus obtained helped determine the generalized results of the front density for different years and seasons. On analysis of such results it was shown that the strongest thermal and optical fronts in the Black Sea are located in the near-coastal area. Nevertheless, analysis of the front density contrasts in the open sea was discovered to be very helpful as well, because it provided important information on the trajectories of the main macro- and mesoscale circulation patterns in the basin such as the Rim Current, Batumi eddy, and eddies of the Anatolian coast. %0 journal article %@ 0964-8305 %A Borges, L.M.S. %D 2014 %J International Biodeterioration and Biodegradation %P 97-104 %R doi:10.1016/j.ibiod.2014.10.003 %T Biodegradation of wood exposed in the marine environment: Evaluation of the hazard posed by marine wood-borers in fifteen European sites %U https://doi.org/10.1016/j.ibiod.2014.10.003 %X Salinity and temperature emerged as the environmental conditions that best explain the occurrence and abundance of wood boring species in the sites surveyed. Three of the species highlighted in this study are warm water species. Therefore their activity might increase in the future, due to global warming. Considering that wood is still a very valuable material for construction, its use for maritime construction should be favoured. Thus research to improve the durability of wooden materials in the marine environment is of paramount importance. %0 journal article %@ 0924-7963 %A Petersen, W. %D 2014 %J Journal of Marine Systems %P 4-12 %R doi:10.1016/j.jmarsys.2014.07.003 %T FerryBox systems: State-of-the-art in Europe and future development %U https://doi.org/10.1016/j.jmarsys.2014.07.003 %X The current state-of-the-art of FerryBox systems are presented, and their usage as part of European observing systems such as Alg@line in the Baltic Sea or the coastal observatory COSYNA in the North Sea is discussed as well as data management systems. An overview of diverse FerryBox measurement activities is provided, covering the wide and varied potential for utilizing FerryBox data. One innovative technical component is the application of newly developed sensors suitable for FerryBox systems that focus on biogeochemical processes. This component could fill currently existing gaps of robust biogeochemical observations in the oceans and may create, together with the high spatial and temporal resolution of FerryBox systems, the possibility for new insights into physical and biogeochemical processes that were impossible to study before. Such new insights could contribute to the European Marine Strategy Framework Directive (MSFD) and include observations of the coastal carbonate system and its interaction with climate change or eutrophication and productivity. %0 journal article %@ 0272-7714 %A Roettgers, R., Heymann, K., Krasemann, H. %D 2014 %J Estuarine, Coastal and Shelf Science %P 148-155 %R doi:10.1016/j.ecss.2014.10.010 %T Suspended matter concentrations in coastal waters: Methodological improvements to quantify individual measurement uncertainty %U https://doi.org/10.1016/j.ecss.2014.10.010 %X Measurements of total suspended matter (TSM) concentration and the discrimination of the particulate inorganic (PIM) and organic matter fraction by the loss on ignition methods are susceptible to significant and contradictory bias errors by: (a) retention of sea salt in the filter (despite washing with deionized water), and (b) filter material loss during washing and combustion procedures. Several methodological procedures are described to avoid or correct errors associated with these biases but no analysis of the final uncertainty for the overall mass concentration determination has yet been performed. Typically, the exact values of these errors are unknown and can only be estimated. Measurements were performed in coastal and estuarine waters of the German Bight that allowed the individual error for each sample to be determined with respect to a systematic mass offset. This was achieved by using different volumes of the sample and analyzing the mass over volume relationship by linear regression. The results showed that the variation in the mass offset is much larger than expected (mean mass offset: 0.85 ± 0.84 mg, range: −2.4 – 7.5 mg) and that it often leads to rather large relative errors even when TSM concentrations were high. Similarly large variations were found for the mass offset for PIM measurements. Correction with a mean offset determined with procedural control filters reduced the maximum error to <60%. The determination errors for the TSM concentration was <40% when three different volume were used, and for the majority of the samples the error was <10%. When six different volumes were used and outliers removed, the error was always <25%, very often errors of only a few percent were obtained. The approach proposed here can determine the individual determination error for each sample, is independent of bias errors, can be used for TSM and PIM determination, and allows individual quality control for samples from coastal and estuarine waters. It should be possible to use the approach in oceanic or fresh water environments as well. The possibility of individual quality control will allow mass-specific optical properties to be determined with better resolved uncertainties and, hence, lower statistical variability, greatly improving our capability to model inherent optical properties of natural particles and its natural variability, e.g. dependence on particle size and the complex refractive index. %0 journal article %@ 0196-2892 %A Maresca, S., Braca, P., Horstmann, J., Grasso, R. %D 2014 %J IEEE Transactions on Geoscience and Remote Sensing %N 8 %P 5056-5071 %R doi:10.1109/TGRS.2013.2286741 %T Maritime Surveillance Using Multiple High-Frequency Surface-Wave Radars %U https://doi.org/10.1109/TGRS.2013.2286741 8 %X In the last decades, great interest has been directed toward low-power high-frequency (HF) surface-wave radars as long-range early warning tools in maritime-situational-awareness applications. These sensors, developed for ocean remote sensing, provide an additional source of information for ship detection and tracking, by virtue of their over-the-horizon coverage capability and continuous-time mode of operation. Unfortunately, they exhibit many shortcomings that need to be taken into account, such as poor range and azimuth resolution, high nonlinearity, and significant presence of clutter. In this paper, radar detection, multitarget tracking, and data fusion (DF) techniques are applied to experimental data collected during an HF-radar experiment, which took place between May and December 2009 on the Ligurian coast of the Mediterranean Sea. The system performance is defined in terms of time on target (ToT), false alarm rate (FAR), track fragmentation, and accuracy. A full statistical characterization is provided using one month of data. The effectiveness of the tracking and DF procedures is shown in comparison to the radar detection algorithm. In particular, the detector's FAR is reduced by one order of magnitude. Improvements, using the DF of the two radars, are also reported in terms of ToT as well as accuracy. %0 book part %@ %A Karimova, S.S., Gade, M. %D 2014 %J Remote Sensing of the African Seas %P 357-378 %R doi:10.1007/978-94-017-8008-7_18 %T Eddies in the Red Sea as seen by Satellite SAR Imagery %U https://doi.org/10.1007/978-94-017-8008-7_18 %X We present the results of our observations of mesoscale and sub-mesoscale eddies in the Red Sea based on Synthetic Aperture Radar (SAR) imagery. The dataset used includes about 500 Envisat Advanced SAR (ASAR) images obtained in 2006–2011 over the Red Sea. We found more than 1,000 sub-mesoscale eddies, which manifest in the SAR imagery both due to surfactant films (“black” eddies) and wave/current interactions (“white” eddies), depending on the local wind speed. Sub-mesoscale eddies in the Red Sea seem to be more innumerous than in other inner seas, presumably due to a relatively deep upper mixed layer in this basin. Moreover, more than 50 meso- and basin-scale eddies were found, whose rotation was mostly anti-cyclonic and whose diameters ranged up to approximately 200 km. Most of the basin-scale eddies were found between 21 and 24°N, which is in agreement with earlier observations and with numerical modeling. %0 journal article %@ 1094-4087 %A Roettgers, R., Mc Kee, D., Utschig, C. %D 2014 %J Optics express %N 21 %P 25093-25108 %R doi:10.1364/OE.22.025093 %T Temperature and salinity correction coefficients for light absorption by water in the visible to infrared spectral region %U https://doi.org/10.1364/OE.22.025093 21 %X The light absorption coefficient of water is dependent on temperature and concentration of ions, i.e. the salinity in seawater. Accurate knowledge of the water absorption coefficient, a, and/or its temperature and salinity correction coefficients, ΨT and ΨS, respectively, is essential for a wide range of optical applications. Values are available from published data only at specific narrow wavelength ranges or at single wavelengths in the visible and infrared regions. ΨT and ΨS were therefore spectrophotometrically measured throughout the visible, near, and short wavelength infrared spectral region (400 to ~2700 nm). Additionally, they were derived from more precise measurements with a point-source integrating-cavity absorption meter (PSICAM) for 400 to 700 nm. When combined with earlier measurements from the literature in the range of 2600 – 14000 nm (wavenumber: 3800 – 700 cm−1), the coefficients are provided for 400 to 14000 nm (wavenumber: 25000 to 700 cm−1). %0 conference lecture %@ %A North, R.P., Angel-Benavides, I.M., Baschek, B., Molemaker, M.J., Marmorino, G. %D 2014 %J Ocean Sciences Meeting 2014 %T Quantifying Submesoscale Features Captured in the Coastal Region of the Southern California Bight %U %X %0 conference lecture (invited) %@ %A Horstmann, J., Seemann, J., Cysewski, M., Carrasco, R., Stresser, M., Wu, L.-C., Ziemer, F. %D 2014 %J 35th Canadian Symposium on Remote Sensing and IGARSS 2014 %T Hydrographic Parameters Retrieved from Grazing Incidence Coherent Radars %U %X %0 HZG report %@ 2191-7833 %A Clark, S., Schroeder, F., Baschek, B. %D 2014 %J %T The influence of large offshore wind farms on the North Sea and Baltic Sea - A comprehensive literature review %U %X %0 conference poster %@ %A Hieronymi, M. %D 2014 %J 22nd Ocean Optics Conference %T Wave shadowing effects on the light transfer at the ocean surface %U %X %0 journal article %@ 1726-4170 %A Heim, B., Abramova, E., Doerffer, R., Günther, F., Hölemann, J., Kraberg, A., Lantuit, H., Loginova, A., Martynov, F., Overduin, P.P., Wegner, C. %D 2014 %J Biogeosciences %N 15 %P 4191-4210 %R doi:10.5194/bg-11-4191-2014 %T Ocean colour remote sensing in the southern Laptev Sea: evaluation and applications %U https://doi.org/10.5194/bg-11-4191-2014 15 %X Enhanced permafrost warming and increased Arctic river discharges have heightened concern about the input of terrigenous matter into Arctic coastal waters. We used optical operational satellite data from the ocean colour sensor MERIS (Medium-Resolution Imaging Spectrometer) aboard the ENVISAT satellite mission for synoptic monitoring of the pathways of terrigenous matter on the shallow Laptev Sea shelf. Despite the high cloud coverage in summer that is inherent to this Arctic region, time series from MERIS satellite data from 2006 on to 2011 could be acquired and were processed using the Case-2 Regional Processor (C2R) for optically complex surface waters installed in the open-source software ESA BEAM-VISAT.Since optical remote sensing using ocean colour satellite data has seen little application in Siberian Arctic coastal and shelf waters, we assess the applicability of the calculated MERIS C2R parameters with surface water sampling data from the Russian-German ship expeditions LENA2008,LENA2010 and TRANSDRIFT-XVII taking place in August 2008 and August and September 2010 in the southern Laptev Sea. The shallow Siberian shelf waters are optically not comparable to the deeper, more transparent waters of the Arctic Ocean. The inner-shelf waters are characterized by low transparencies,due to turbid river water input, terrestrial input by coastal erosion, resuspension events and, therefore, high background concentrations of suspended particulate matter and coloured dissolved organic matter.We compared the field-based measurements with the satellite data that are closest in time. The match-up analyses related to LENA2008 and LENA2010 expedition data show the technical limits of matching in optically highly heterogeneous and dynamic shallow inner-shelf waters. The matchup analyses using the data from the marine TRANSDRIFT expedition were constrained by several days' difference between a match-up pair of satellite-derived and in situ parameters but are also based on the more stable hydrodynamic conditions of the deeper inner-and the outer-shelf waters.The relationship of satellite-derived turbidity-related parameters versus in situ suspended matter from TRANSDRIFT data shows that the backscattering coefficient C2R-bb-spm can be used to derive a Laptev-Sea-adapted SPM algorithm.Satellite-derived Chl a estimates are highly overestimated by minimum factor of 10 if applied to the inner-shelf region due to elevated concentrations of terrestrial organic matter.To evaluate the applicability of ocean colour remote sensing,we include the visual analysis of lateral hydrographical features. The mapped turbidity-related MERIS C2R parameters show that the Laptev Sea is dominated by resuspension above submarine shallow banks and by frontal instabilities such as frontal meanders with amplitudes up to 30 km and eddies and filaments with horizontal scales up to 100 km that prevail throughout the sea-ice-free season. The widespread turbidity above submarine shallow banks indicates innershelf vertical mixing that seems frequently to reach down to P submarine depths of a minimum of 10 m. The resuspension events and the frontal meanders, filaments and eddies indicate enhanced vertical mixing being widespread on the inner shelf.It is a new finding for the Laptev Sea that numerous frontal instabilities are made visible, and how highly time-dependent and turbulent the Laptev Sea shelf is. The meanders, filaments and eddies revealed by the ocean colour parameters indicate the lateral transportation pathways of terrestrial and living biological material in surface waters. %0 journal article %@ 1867-1381 %A van Zadelhoff, G.-J., Stoffelen, A., Vachon, P. W., Wolfe, J., Horstmann, J., Belmonte Rivas, M. %D 2014 %J Atmospheric Measurement Techniques %N 2 %P 437-449 %R doi:10.5194/amt-7-437-2014 %T Retrieving hurricane wind speeds using cross-polarization C-band measurements %U https://doi.org/10.5194/amt-7-437-2014 2 %X Hurricane-force wind speeds can have a large societal impact and in this paper microwave C-band cross-polarized (VH) signals are investigated to assess if they can be used to derive extreme wind-speed conditions. European satellite scatterometers have excellent hurricane penetration capability at C-band, but the vertically (VV) polarized signals become insensitive above 25 m s−1. VV and VH polarized backscatter signals from RADARSAT-2 SAR imagery acquired during severe hurricane events were compared to collocated SFMR wind measurements acquired by NOAA's hurricane-hunter aircraft. From this data set a geophysical model function (GMF) at strong-to-extreme/severe wind speeds (i.e., 20 m s−1 < U10 < 45 m s−1) is derived. Within this wind speed regime, cross-polarized data showed no distinguishable loss of sensitivity and as such, cross-polarized data can be considered a good candidate for the retrieval of strong-to-severe wind speeds from satellite instruments. The upper limit of 45 m s−1 is defined by the currently available collocated data. The validity of the derived relationship between wind speed and VH backscatter has been evaluated by comparing the cross-polarized signals to two independent wind-speed data sets (i.e., short-range ECMWF numerical weather prediction (NWP) model forecast winds and the NOAA best estimate 1-minute maximum sustained winds). Analysis of the three comparison data sets confirm that cross-polarized signals from satellites will enable the retrieval of strong-to-severe wind speeds where VV or horizontal (HH) polarization data has saturated. The VH backscatter increases exponentially with respect to wind speed (linear against VH [dB]) and a near-real-time assessment of maximum sustained wind speed is possible using VH measurements. VH measurements thus would be an extremely valuable complement on next-generation scatterometers for hurricane forecast warnings and hurricane model initialization. %0 dataset %@ %A Riethmüller, R., Röttgers, R. %D 2014 %J PANGAEA %R doi:10.1594/PANGAEA.829678 %T Station list and links to master tracks in different resolutions of HEINCKE cruise HE407 %U https://doi.org/10.1594/PANGAEA.829678 %X %0 journal article %@ 0272-7714 %A Mielck, F., Bartsch, I., Hass, H.C., Wölfl, A.-C., Bürk, D., Betzler, C. %D 2014 %J Estuarine, Coastal and Shelf Science %P 1-11 %R doi:10.1016/j.ecss.2014.03.016 %T Predicting spatial kelp abundance in shallow coastal waters using the acoustic ground discrimination system RoxAnn %U https://doi.org/10.1016/j.ecss.2014.03.016 %X Kelp forests represent a major habitat type in coastal waters worldwide and their structure and distribution is predicted to change due to global warming. Despite their ecological and economical importance, there is still a lack of reliable spatial information on their abundance and distribution. In recent years, various hydroacoustic mapping techniques for sublittoral environments evolved. However, in turbid coastal waters, such as off the island of Helgoland (Germany, North Sea), the kelp vegetation is present in shallow water depths normally excluded from hydroacoustic surveys. In this study, single beam survey data consisting of the two seafloor parameters roughness and hardness were obtained with RoxAnn from water depth between 2 and 18 m. Our primary aim was to reliably detect the kelp forest habitat with different densities and distinguish it from other vegetated zones. Five habitat classes were identified using underwater-video and were applied for classification of acoustic signatures. Subsequently, spatial prediction maps were produced via two classification approaches: Linear discriminant analysis (LDA) and manual classification routine (MC). LDA was able to distinguish dense kelp forest from other habitats (i.e. mixed seaweed vegetation, sand, and barren bedrock), but no variances in kelp density. In contrast, MC also provided information on medium dense kelp distribution which is characterized by intermediate roughness and hardness values evoked by reduced kelp abundances. The prediction maps reach accordance levels of 62% (LDA) and 68% (MC). The presence of vegetation (kelp and mixed seaweed vegetation) was determined with higher prediction abilities of 75% (LDA) and 76% (MC). Since the different habitat classes reveal acoustic signatures that strongly overlap, the manual classification method was more appropriate for separating different kelp forest densities and low-lying vegetation. It became evident that the occurrence of kelp in this area is not simply linked to water depth. Moreover, this study shows that the two seafloor parameters collected with RoxAnn are suitable indicators for the discrimination of different densely vegetated seafloor habitats in shallow environments. %0 journal article %@ 2070-2000 %A Eschenbach, C. %D 2014 %J INPRINT / Land-Ocean Interactions in the Coastal Zone %P 29-32 %T The Coastal Observing System for Northern and Arctic Seas - Continuing Improvement of Data Collection and Dissemination %U %X Experiences regarding the challenge to convey COSYNA’s scientific data and knowledge to the public and to stakeholders are stressed here. These technical and communicational challenges include (1) elaborated data access through advanced portal techniques and (2) feedback on and improvement of COSYNA products through interaction with (potential) users. The particular purpose of these efforts is to ensure COSYNA products are useful and applicable. %0 journal article %@ 0272-7714 %A Newton, A., Icely, J., Cristina, S., Brito, A., Cardoso, A.C., Colijn, F., Riva, S.D., Gertz, F., Hansen, J.W., Holmer, M., Ivanova, K., Leppäkoski, E., Canu, D.M., Mocenni, C., Mudge, S., Murray, N., Pejrup, M., Razinkovas, A., Reizopoulou, S., Pérez-Ruzafa, A., Schernewski, G., Schubert, H., Carr, L., Solidoro, C., Viaroli, P., Zaldívar, J.-M. %D 2014 %J Estuarine, Coastal and Shelf Science %P 95-122 %R doi:10.1016/j.ecss.2013.05.023 %T An overview of ecological status, vulnerability and future perspectives of European large shallow, semi-enclosed coastal systems, lagoons and transitional waters %U https://doi.org/10.1016/j.ecss.2013.05.023 %X Although some of the systems are transitional waters under the Water Framework Directive, this is not the case for all of the systems. The paper adopts a Driver-Pressure-State-Impact-Response approach to analyse the ecological status, vulnerability and future perspectives of these systems in the context of global change. %0 conference paper %@ %A Wollschlaeger, J., Voss, D., Zielinski, O., Petersen, W. %D 2014 %J IEEE Conference Publications, Sensor Systems for a Changing Ocean, SSCO 2014 %P 1-6 %R doi:10.1109/SSCO.2014.7292894 %T Continuous observations of biological and environmental parameters by optical absorption and fluorescence – special focus on an integrating cavity approach %U https://doi.org/10.1109/SSCO.2014.7292894 %X To meet the requirements of increasing environmental awareness in aquatic ecosystems, optical techniques offer a fast and reliable opportunity for a wide range of application providing spatio-temporal measurements. Within the work package 5 of NeXOS innovative, compact, and cost efficient multifunctional sensor systems for optical measurements of marine environmental parameters will be developed. Addressed parameters include phytoplankton biomass and taxonomic composition, total suspended matter and chromophoric dissolved organic matter (CDOM), as well as hazardous substances, e.g. polycyclic aromatic hydrocarbons (PAHs). Requiring comparable less effort, optical methods are a convenient and noninvasive way to derive information on the optical active substances in different water bodies. Various approaches and devices are available, either aiming on the determination of the wateŕs inherent optical properties or on measuring the fluorescence properties of the different constituents. This contribution summarizes the objectives and approaches within the optical sensor development of the NeXOS project with a special focus on an integrating cavity approach. This approach overcomes the two common problems occurring in classical absorption measurement of seawater: (i) usually low concentration of absorbing material in the water negatively affecting accurate measurements of untreated samples, and (ii) errors introduced by light scattering on particles, which require empirical corrections of the measurements to obtain good accuracy. An example for a device based on an integrating cavity is the point-source integrating cavity absorption meter (PSICAM). Because of its advantages, an adaptation of the PSICAM for continuous flow-through operation is of interest to provide high resolution measurements of absorption coefficients with good accuracy. The continuous observation system is planned to be used stand-alone or in combination with unattended systems, e.g. FerryBox.- In this contribution, the setup and first field results of the flow-through-PSICAM (ft-PSICAM) are reviewed. Furthermore, absorption coefficients as proxies for chlorophyll-a and total suspended matter are evaluated. Within the optical sensor package of NeXOS, a further objective is the development of a matrix-fluorescence sensor with flexible wavelength configuration for the detection and characterization of dissolved substances, such as CDOM and PAHs. Here, objectives and first approaches will be presented with special focus on CDOM fluorescence as main linkage to the ft-PSICAM. Finally, future plans for both instruments as well as their combination will be presented. In summary, both approaches have the potential to be multi-parameter instruments for high-resolution measurements of environmental relevant parameters. %0 journal article %@ 1726-4170 %A Friedrich, J., Janssen, F., Aleynik, D., Bange, H. W., Boltacheva, N., agatay, M. N., Dale, A. W., Etiope, G., Erdem, Z., Geraga, M., Gilli, A., Gomoiu, M. T., Hall, P. O. J., Hansson, D., He, Y., Holtappels, M., Kirf, M. K., Kononets, M., Konovalov, S., Lichtschlag, A., Livingstone, D. M., Marinaro, G., Mazlumyan, S., Naeher, S., North, R. P., Papatheodorou, G., Pfannkuche, O., Prien, R., Rehder, G., Schubert, C. J., Soltwedel, T., Sommer, S., Stahl, H., Stanev, E. V., Teaca, A., Tengberg, A., Waldmann, C., Wehrli, B., Wenzhoefer, F. %D 2014 %J Biogeosciences %P 1215-1259 %R doi:10.5194/bg-11-1215-2014 %T Investigating hypoxia in aquatic environments: diverse approaches to addressing a complex phenomenon %U https://doi.org/10.5194/bg-11-1215-2014 %X Temporal dynamics and spatial patterns of hypoxia were analyzed in field studies in various aquatic environments, including the Baltic Sea, the Black Sea, Scottish and Scandinavian fjords, Ionian Sea lagoons and embayments, and Swiss lakes. Examples of episodic and rapid (hours) occurrences of hypoxia, as well as seasonal changes in bottom-water oxygenation in stratified systems, are discussed. Geologically driven hypoxia caused by gas seepage is demonstrated. Using novel technologies, temporal and spatial patterns of water-column oxygenation, from basin-scale seasonal patterns to meter-scale sub-micromolar oxygen distributions, were resolved. Existing multidecadal monitoring data were used to demonstrate the imprint of climate change and eutrophication on long-term oxygen distributions. Organic and inorganic proxies were used to extend investigations on past oxygen conditions to centennial and even longer timescales that cannot be resolved by monitoring. The effects of hypoxia on faunal communities and biogeochemical processes were also addressed in the project. An investigation of benthic fauna is presented as an example of hypoxia-devastated benthic communities that slowly recover upon a reduction in eutrophication in a system where naturally occurring hypoxia overlaps with anthropogenic hypoxia. Biogeochemical investigations reveal that oxygen intrusions have a strong effect on the microbially mediated redox cycling of elements. Observations and modeling studies of the sediments demonstrate the effect of seasonally changing oxygen conditions on benthic mineralization pathways and fluxes. Data quality and access are crucial in hypoxia research. Technical issues are therefore also addressed, including the availability of suitable sensor technology to resolve the gradual changes in bottom-water oxygen in marine systems that can be expected as a result of climate change. Using cabled observatories as examples, we show how the benefit of continuous oxygen monitoring can be maximized by adopting proper quality control. Finally, we discuss strategies for state-of-the-art data archiving and dissemination in compliance with global standards, and how ocean observations can contribute to global earth observation attempts. %0 journal article %@ 0148-0227 %A Xi, H., Larouche, P., Tang, S., Michel, C. %D 2014 %J Journal of Geophysical Research : Oceans %N 6 %P 3392-3406 %R doi:10.1002/2013JC009542 %T Characterization and variability of particle size distributions in Hudson Bay, Canada %U https://doi.org/10.1002/2013JC009542 6 %X Particle size distribution (PSD) plays a significant role in many aspects of aquatic ecosystems, including phytoplankton dynamics, sediment fluxes, and optical scattering from particulates. As of yet, little is known on the variability of particle size distribution in marine ecosystems. In this study, we investigated the PSD properties and variability in Hudson Bay based on measurements from a laser diffractometer (LISST-100X Type-B) in concert with biogeochemical parameters collected during summer 2010. Results show that most power-law fitted PSD slopes ranged from 2.5 to 4.5, covering nearly the entire range observed for natural waters. Offshore waters showed a predominance of smaller particles while near the coast, the effect of riverine inputs on PSD were apparent. Particulate inorganic matter contributed more to total suspended matter in coastal waters leading to lower PSD slopes than offshore. The depth distribution of PSD slopes shows that larger particles were associated with the pycnocline. Below the pycnocline, smaller particles dominated the spectra. A comparison between a PSD slope-based method to derive phytoplankton size class (PSC) and pigment-based derived PSC showed the two methods agreed relatively well. This study provides valuable baseline information on particle size properties and phytoplankton composition estimates in a sub-arctic environment subject to rapid environmental change. %0 journal article %@ 1990-2573 %A Hieronymi, M. %D 2013 %J Journal of the European Optical Society - Rapid Publications %P 13039 %R doi:10.2971/jeos.2013.13039 %T Monte Carlo code for the study of the dynamic light field at the wavy atmosphere-ocean interface %U https://doi.org/10.2971/jeos.2013.13039 %X A radiative transfer model has been developed to study the solar radiation budget at the wave-deflected air-sea interface. The model is used to characterize fluctuations of the underwater light field, i.e. down- and upwelling irradiance, irradiance reflectance, and upwelling radiance just below the surface, subject to changing sun zenith angles and percentages of diffuse sky radiation to the total insolation. The focusing of sunlight is most effective under clear skies; the variability of downwelling irradiance is significantly smaller under overcast conditions. In general, maximum and deep-reaching fluctuations arise at high sun positions, but the behaviour is much more differentiated and exceptions are discussed. Furthermore, wave shadowing effects have been studied; these become increasingly important for low sun elevations. There are indications that the light transmission into water up to now is overestimated for solar zenith angles near the horizon. %0 conference paper %@ %A Hieronymi, M., Macke, A. %D 2013 %J AIP Conference Proceedings, International Radiation Symposium 2012 %P 915-918 %R doi:10.1063/1.4804920 %T Wave-induced irradiance variability in the upper ocean from modeling and observations %U https://doi.org/10.1063/1.4804920 %X A Monte Carlo based radiative transfer model has been developed to reproduce the availability of solar radiation down to 100 m water depth. The model is especially designed to simulate spatial high resolution downwelling irradiance Ed fluctuations that arise from the de-/focusing effect of surface waves. The potential depth-impact of single waves, including capillary and swell waves, and of all possible sea states is assessed by considering favorable conditions for light focusing. %0 journal article %@ 0972-9860 %A Schroeder, F., Boer, M., Wijanarko, D.A. %D 2013 %J Asian Journal of Water, Environment and Pollution %N 1 %P 25-39 %T Development and Application of the MERMAID Water Quality Monitoring Station in the Brantas River, Java, Indonesia %U 1 %X The design, development and operation of an automated water quality station at the banks of the Brantas River, Java, Indonesia is described. The objective of the work was to prove that such a station can be operated in tropical areas with trained local personnel. By designing and building a modular system within a transportable container, a generalised system that can be applied to other tropical or subtropical regions was developed. The main problem in tropical waters — biofouling of sensors – was solved by automated cleaning procedures that include pressure cleaning with acidified water and chlorination. Low maintenance requirements could be achieved by a completely automated operation and remote maintenance via phone and internet. The different components of the system – water inlet, hydraulic circuit, data management – are described in detail. The performance and the costs of the automated water quality station are discussed. %0 journal article %@ 0972-9860 %A Schroeder, F., Knauth, H.-D. %D 2013 %J Asian Journal of Water, Environment and Pollution %N 1 %P 55-72 %T Water Quality Time-series Data of the Lower Brantas River, East Java, Indonesia: Results from an Automated Water Quality Monitoring Station %U 1 %X Using an automated water quality station in the lower Brantas River, East Java, Indonesia, highly time-resolved time series (1 min^1) of main parameters that govern water quality have been measured (oxygen, chlorophyll-a, turbidity, nutrients, total inorganic and organic carbon) from 2003 to 2008. All parameters showed distinct seasonal variations related to dry and wet seasons. Due to the large input of organic material from sewage and industry into the river the most important parameter is the dissolved oxygen that displays a distinct seasonal behaviour with relatively large values during wet season and very low values in dry season. In addition, during dry season high variations between day and night were observed with zero oxygen concentrations at night. From highly time-resolved oxygen time series the main metabolic rates (primary production, respiration) together with atmospheric exchange rates could be calculated in a semi-quantitative way. From this, it could be estimated that the anthropogenic carbon input into the river has to be reduced from about 70 t/d BOD equivalents to at least 33 t/d in order to prevent anaerobic conditions. %0 conference object %@ %A Breitbach, G., Krasemann, H. %D 2013 %J Tagungsband - Kuestenforschung, Kuestennutzung und Kuestenschutz, Einladung zum Dialog %P 86 %T COSYNA Datenmanagement %U %X %0 journal article %@ 1726-4170 %A Oerek, H., Doerffer, R., Roettgers, R., Boersma, M., Wiltshire, K.H. %D 2013 %J Biogeosciences %N 11 %P 7081-7094 %R doi:10.5194/bg-10-7081-2013 %T Contribution to a bio-optical model for remote sensing of Lena River water %U https://doi.org/10.5194/bg-10-7081-2013 11 %X Bio-optical measurements and sampling were carried out in the delta of the Lena River (northern Siberia, Russia) between 26 June and 4 July 2011. The aim of this study was to determine the inherent optical properties of the Lena water, i.e., absorption, attenuation, and scattering coefficients, during the period of maximum runoff. This aimed to contribute to the development of a bio-optical model for use as the basis for optical remote sensing of coastal water of the Arctic. In this context the absorption by CDOM (colored dissolved organic matter) and particles, and the concentrations of total suspended matter, phytoplankton-pigments, and carbon were measured. CDOM was found to be the most dominant parameter affecting the optical properties of the river, with an absorption coefficient of 4.5–5 m−1 at 442 nm, which was almost four times higher than total particle absorption values at visible wavelength range. The wavelenght-dependence of absorption of the different water constituents was chracterized by determining the semi logarithmic spectral slope. Mean CDOM, and detritus slopes were 0.0149 nm−1(standard deviation (stdev) = 0.0003, n = 18), and 0.0057 nm−1 (stdev = 0.0017, n = 19), respectively, values which are typical for water bodies with high concentrations of dissolved and particulate carbon. Mean chlorophyll a and total suspended matter were 1.8 mg m−3 (stdev = 0.734 n = 18) and 31.9 g m−3 (stdev = 19.94, n = 27), respectively. DOC (dissolved organic carbon) was in the range 8–10 g m−3 and the total particulate carbon (PC) in the range 0.25–1.5 g m−3. The light penetration depth (Secchi disc depth) was in the range 30–90 cm and was highly correlated with the suspended matter concentration. The period of maximum river runoff in June was chosen to obtain bio-optical data when maximum water constituents are transported into the Laptev Sea. However, we are aware that more data from other seasons and other years need to be collected to establish a general bio-optical model of the Lena water and conclusively characterize the light climate with respect to primary production. %0 conference poster %@ %A Breitbach, G., Beringer, S., Behr, D. %D 2013 %J Datenportal Deutsche Meeresforschung, MaNIDA, 1. Nutzerworkshop %T Case Study North Sea %U %X %0 journal article %@ 1616-7341 %A Wollschlaeger, J., Grunwald, M., Roettgers, R., Petersen, W. %D 2013 %J Ocean Dynamics %N 7 %P 761-775 %R doi:10.1007/s10236-013-0629-x %T Flow-through PSICAM: a new approach for determining water constituents absorption continuously %U https://doi.org/10.1007/s10236-013-0629-x 7 %X Determination of spectral absorption coefficients in seawater is of interest for biologic oceanographers for various reasons, but faces also several problems, especially if continuous measurements are required. We introduce the flow-through point-source integrating cavity absorption meter (ft-PSICAM) as a new tool for the continuous measurement of spectral absorption coefficients in a range of 400–710 nm. A description of the system is given and its performance in comparison with a conventional PSICAM has been evaluated on two cruises in 2011 in the southern part of the North Sea (German Bight). Furthermore, factors influencing the measurement are discussed. When comparing the data of both systems, a good linear correlation has been found for all wavelengths (r2 > 0.91). Deviations between systems were different with respect to the wavelength examined with slopes of linear fits between 1.1 and 1.65 and offsets between −0.1 and 0.01, with the higher values at shorter wavelengths. They were caused mainly due to contamination of the flow-through system during operation by phytoplankton particles. Focus was also laid on the measurement of chlorophyll-a concentrations ([chl-a]) and total suspended matter concentrations ([TSM]) on the basis of absorption coefficient determination. For this, appropriate relationships were established and [chl-a] and [TSM] values were calculated from the relevant ft-PSICAM absorption coefficients. Their progression matches well with the progression of fluorescence and turbidity measurements made in parallel. In conclusion, the ft-PSICAM is successful in measuring spectral absorption coefficients continuously and resolving relative changes in seawater optical properties. %0 conference lecture %@ %A Quante, M., Colijn, F. %D 2013 %J The dynamics of shelf seas, Workshop %T The international North Sea Region Climate Change Assessment (NOSCCA) - An analysis of the scientific legitimate knowledge for science and decision making %U %X %0 journal article %@ 0972-9860 %A Nugrahadi, M. %A |Duwe, K., Schroeder, F., Goldmann, D. %D 2013 %J Asian Journal of Water, Environment and Pollution %N 1 %P 117-128 %T Seasonal Variability of the Water Residence Time in the Madura Strait, East Java, Indonesia %U 1 %X A Lagrangian particle tracer method embedded within a 3-D finite difference hydrodynamic model is used to study the transport and exchange processes in a semi-enclosed water of Madura Strait, East Java, Indonesia. The 3-D hydrodynamic model forcing functions consist of tidal elevation at north and east open boundary, river discharge of Brantas River estuaries, and monsoonal wind. The validated model successfully estimated the variability of residence time. The calculation results show that water residence times in Madura Strait and especially in its tributaries are mainly governed by the strength of river discharges, whereas the direction of advection is influenced mainly by monsoon wind directions and less by the tide-induced residual current. %0 conference poster %@ %A Breitbach, G., Beringer, S., Krasemann, H. %D 2013 %J Datenportal Deutsche Meeresforschung, MaNIDA, 1. Nutzerworkshop %T Data Quality %U %X %0 journal article %@ 0948-4280 %A Merckelbach, L. %D 2013 %J Journal of Marine Science and Technology %N 1 %P 75-86 %R doi:10.1007/s00773-012-0189-7 %T On the probability of underwater glider loss due to collision with a ship %U https://doi.org/10.1007/s00773-012-0189-7 1 %X The demonstrated utility of underwater gliders as measurement platforms for the open ocean has sparked a growing interest in operating them in shallow coastal areas too. Underwater gliders face additional challenges in this environment, such as strong (tidal) currents and high shipping intensity. This work focuses on the probability of losing a glider through a collision with a ship. A ship density map is constructed for the German Bight from observed ship movements derived from automatic identification system data. A simple probability model is developed to convert ship densities into collision probabilities. More realistic—but also more computationally expensive—Monte Carlo simulations were carried out for verification. This model can be used to generate geographic maps showing the probability of glider loss due to collisions. Such maps are useful when planning glider missions. The method developed herein is also applicable to other types of AUVs. %0 journal article %@ 1094-4087 %A Tan, H., Doerffer, R., Oishi, T., Tanaka, A. %D 2013 %J Optics express %N 16 %P 18697-18711 %R doi:10.1364/OE.21.018697 %T A new approach to measure the volume scattering function %U https://doi.org/10.1364/OE.21.018697 16 %X We present a novel optical approach to measure the volume scattering function (VSF) by image detection. The instrument design, based upon a combination of two reflectors, uses a unique measurement principle and allows the rapid simultaneous determination of scattering at a wide range of angles. The advantages of the newly developed scattering meter are that: 1) it can determine the scattering function from 8° to 172° at 1° intervals without changing the sensitivity of the detector, without moving any optical parts, and can do so within a few seconds, 2) the unique optical design facilitates determination of the spectral VSF over the full visible spectrum, i.e. it can obtain the VSF at a specific wavelength with an optional wavelength-resolution. Measurements under controlled conditions for the assessment of the instrument agreed well with theoretically predicted scattering functions. Measurements with cultured phytoplankton of different species revealed a significant variety of the VSF together with spectral variation. The observed results will stimulate and improve radiative transfer and/or two-flow models of light in the ocean, which is an important role for ocean color remote sensing algorithm development, particularly for coastal regions. %0 journal article %@ 1545-598X %A Bruno, L., Braca, P., Horstmann, J., Vespe, M. %D 2013 %J IEEE Geoscience and Remote Sensing Letters %N 4 %P 850-854 %R doi:10.1109/LGRS.2012.2226203 %T Experimental Evaluation of the Range–Doppler Coupling on HF Surface Wave Radars %U https://doi.org/10.1109/LGRS.2012.2226203 4 %X High-frequency surface wave radar (HFSWR) is used in oceanography to monitor surface wind waves and currents and, more recently, to detect ships in maritime surveillance. The radar accuracy is affected by range-Doppler coupling, which yields a displacement in the measured range proportional to the target radial velocity, i.e., the Doppler shift in the returned pulse. Although in oceanography this effect is usually not accounted for, its relevance grows in ship detection. In this letter, we present the results of two experimental data sets showing displacements in the HFSWR range measurements of up to 300 m and confirming the theoretical analysis. Furthermore, we show that the correction based on theoretical arguments, achieved by the statistical correlation between the range and Doppler measurements, provides remarkable improvement in the radar accuracy. %0 conference poster %@ %A Breitbach, G., Krasemann, H. %D 2013 %J Kuestenforschung, Kuestennutzung und Kuestenschutz, Einladung zum Dialog %T COSYNA Datenmanagement %U %X %0 journal article %@ 0739-0572 %A Vicen-Bueno, R., Horstmann, J., Terril, E., de Paolo, T., Dannenberg, J. %D 2013 %J Journal of Atmospheric and Oceanic Technology %N 1 %P 127-139 %R doi:10.1175/JTECH-D-12-00027.1 %T Real-Time Ocean Wind Vector Retrieval from Marine Radar Image Sequences Acquired at Grazing Angle %U https://doi.org/10.1175/JTECH-D-12-00027.1 1 %X This paper proposes a novel algorithm for retrieving the ocean wind vector from marine radar image sequences in real time. It is presented as an alternative to mitigate anemometer problems, such as blockage, shadowing, and turbulence. Since wind modifies the sea surface, the proposed algorithm is based on the dependence of the sea surface backscatter on wind direction and speed. This algorithm retrieves the wind vector using radar measurements in the range of 200–1500 m. Wind directions are retrieved from radar images integrated over time and smoothed (averaged) in space by searching for the maximum radar cross section in azimuth as the radar cross section is largest for upwind directions. Wind speeds are retrieved by an empirical third-order polynomial geophysical model function (GMF), which depends on the range distance in the upwind direction to a preselected intensity level and the intensity level. This GMF is approximated from a dataset of collocated in situ wind speed and radar measurements (~31 000 measurements, ~56 h). The algorithm is validated utilizing wind and radar measurements acquired on the Research Platform (R/P) FLIP (for Floating Instrumentation Platform) during the 13-day Office of Naval Research experiment on High-Resolution Air–Sea Interaction (HiRes) in June 2010. Wind speeds ranged from 4 to 22 m s−1. Once the proposed algorithm is tuned, standard deviations and biases of 14° and −1° for wind directions and of 0.8 and −0.1 m s−1 for wind speeds are observed, respectively. Additional studies of uncertainty and error of the retrieved wind speed are also reported. %0 conference object %@ %A Breitbach, G., Krasemann, H. %D 2013 %J Book of Abstracts, International Conference on Marine Data and Information Systems, IMDIS 2013 %P 141-142 %T A new Approach in Data Management for an Integrated Coastal Observation System %U %X %0 conference poster %@ %A Flampouris, S., Seemann, J., Ziemer, F. %D 2013 %J 10th EGU General Assembly 2013 %T Wave heave spectra from radar Doppler velocities at extreme low grazing angles %U %X %0 conference lecture %@ %A Petersen, W. %D 2013 %J 5th FerryBox Workshop %T FerryBox systems: State-of-the-art in Europe and future development %U %X %0 conference object %@ 1607-7962 %A Flampouris, S., Seemann, J., Ziemer, F. %D 2013 %J Geophysical Research Abstracts %P 12483-1 %T Wave heave spectra from radar Doppler velocities at extreme low grazing angles %U %X No abstract %0 conference lecture %@ %A Riethmueller, R., Floeser, G., Onken, R., Burchard, H. %D 2013 %J 12th International Coastal Symposium, ICS 2013 %T Connecting thermodynamic properties of the Wadden Sea with residual estuarine circulation %U %X %0 journal article %@ 1042-8275 %A Horstmann, J., Wackermann, C., Falchetti, S., Maresca, S. %D 2013 %J Oceanography %N 2 %P 46-57 %R doi:10.5670/oceanog.2013.30 %T Tropical Cyclone Winds Retrieved from Synthetic Aperture Radar %U https://doi.org/10.5670/oceanog.2013.30 2 %X This paper describes algorithms used to retrieve high-resolution wind fields in tropical cyclone conditions from synthetic aperture radar (SAR) data acquired at C-band with either co-polarization or cross-polarization. Wind directions are estimated from the orientation of wind-induced streaks visible in SAR images using a simple tropical cyclone flow field. Wind speeds are retrieved from the normalized radar cross section taking into account imaging geometry and SAR-retrieved wind direction using a geophysical model function. The algorithms are validated by comparing outputs to a set of SAR images acquired under tropical cyclone conditions. The simulated wind fields are compared to co-located results from the QuikSCAT scatterometer as well as to wind speeds measured by the Stepped Frequency Microwave Radiometer (SFMR) during reconnaissance flights through individual storms. Comparison of QuikSCAT winds to SAR co-polarization data shows that winds can be retrieved with a root mean square error of 17.6° for wind directions and 4.6 m s–1 for wind speeds. Comparison of SAR wind speeds to SFMR data result in a root mean square error of 5.7 m s–1 for co-polarization data and 3.8 m s–1 for cross-polarization data. SAR cross-polarization data are significantly better suited for SAR wind retrieval under tropical cyclone conditions at wind speeds above approximately 20 m s–1. %0 conference lecture %@ %A Hieronymi, M. %D 2013 %J 3rd EOS Topical Meeting on “Blue Photonics” – Optics in the Sea %T The solar radiation budget at the wavy air-sea interface %U %X %0 conference poster %@ %A Hieronymi, M. %D 2013 %J 10th EGU General Assembly 2013 %T The effects of surface waves on the variability of solar radiation in the upper ocean %U %X %0 journal article %@ 0144-1019 %A Gemmrich, J., Baschek, B., Garrett, C. %D 2013 %J Seaways : The Journal of the Nautical Institute %N 9 %P 14-16 %T Rogue waves: Rare but damaging %U 9 %X No abstract %0 journal article %@ 0886-6236 %A Liang, J.-H., Deutsch, C., McWilliams, J.C., Baschek, B., Sullivan, P.P., Chiba, D. %D 2013 %J Global Biogeochemical Cycles %N 3 %P 894-905 %R doi:10.1002/gbc.20080 %T Parameterizing bubble-mediated air-sea gas exchange and its effect on ocean ventilation %U https://doi.org/10.1002/gbc.20080 3 %X Bubbles play an important role in the exchange of gases between the atmosphere and ocean, altering both the rate of exchange and the equilibrium gas saturation state. We develop a parameterization of bubble-mediated gas fluxes for use in Earth system models. The parameterization is derived from a mechanistic model of the oceanic boundary layer that simulates turbulent flows and the size spectrum of bubbles across a range of wind speeds and is compared against other published formulations. Bubble-induced surface supersaturation increases rapidly with wind speed and is inversely related to temperature at a given wind speed, making the effect of bubbles greatest in regions that ventilate the deep ocean. The bubble-induced supersaturation in high-latitude surface waters compensates a substantial fraction of the undersaturation caused by surface cooling. Using a global ocean transport model, we show that this parameterization reproduces observed saturation rate profiles of the noble gas Argon in the deep Atlantic and Pacific Oceans. The abyssal argon supersaturation caused by bubbles varies according to gas solubility, ranging from ∼0.7% for soluble gases like CO2 to ∼1.7% for less soluble gases such as N2. Bubble-induced supersaturation may be significant for biologically active gases such as oxygen. %0 conference poster %@ %A Breitbach, G., Krasemann, H. %D 2013 %J International Conference on Marine Data and Information Systems, IMDIS 2013 %T A new Approach in Data Management for an Integrated Coastal Observation System %U %X %0 journal article %@ 1726-4170 %A Röttgers, R., Koch, B.P. %D 2012 %J Biogeosciences %N 7 %P 2585-2596 %R doi:10.5194/bg-9-2585-2012 %T Spectroscopic detection of a ubiquitous dissolved pigment degradation product in subsurface waters of the global ocean %U https://doi.org/10.5194/bg-9-2585-2012 7 %X Measurements of light absorption by chromophoric dissolved organic matter (CDOM) from subsurface waters of the tropical Atlantic and Pacific Oceans showed a distinct absorption shoulder at 410–415 nm. This indicates an underlying absorption of a pigment whose occurrence is partly correlated with the apparent oxygen utilization (AOU) but also found in the deep chlorophyll maximum. A similar absorption maximum at ~415 nm was also found in the particulate fraction of samples taken below the surface mixing layer and is usually attributed to absorption by respiratory pigments of heterotrophic unicellular organisms. In our study, fluorescence measurements of pre-concentrated dissolved organic matter (DOM) samples from 200–6000 m confirmed a previous study suggesting that the absorption at ~415 nm was related to fluorescence at 650 nm in the oxygen minimum zone. The absorption characteristics of this fluorophore was examined by fluorescence emission/excitation analysis and showed a clear excitation maximum at 415 nm that could be linked to the absorption shoulder in the CDOM spectra. The spectral characteristics of the substance found in the dissolved and particulate fraction did not match with those of chlorophyll a degradation products (as found in a sample from the sea surface) but can be explained by the occurrence of porphyrin pigments from either heterotrophs or autotrophs. Combining the observations of the fluorescence and the 415-nm absorption shoulder suggests that there are high concentrations of a pigment degradation product in subsurface DOM of all major oceans. Most pronouncedly we found this signal in the deep chlorophyll maximum and the oxygen minimum zone of tropical regions. The origin, chemical nature, turnover rate, and fate of this molecule is so far unknown. %0 conference lecture %@ %A Merckelbach, L., Riethmueller, R., Onken, R. %D 2012 %J 2012 Ocean Sciences Meeting, OSM 2012 %T Analysis of sediment resuspension under a pycnocline in the German Bight from combined glider and scanfish observations %U %X %0 report part %@ %A Merckelbach, L., Eschenbach, C. %D 2012 %J Project highlight (cosyna) in advertisement series run by Teledyne Webb Research %T Where could you use a Slocum glider? %U %X %0 journal article %@ 0924-7963 %A Meyer, S., Caldarone, E.M., Chicharo, M.A., Clemmesen, C., Faria, A.M., Faulk, C., Folkvord, A., Holt, G.J., Hoeie, H., Kanstinger, P., Malzahn, A., Moran, D., Petereit, C., Stoettrup, J.G., Peck, M.A. %D 2012 %J Journal of Marine Systems %P 11-24 %R doi:10.1016/j.jmarsys.2011.09.010 %T On the edge of death: Rates of decline and lower thresholds of biochemical condition in food-deprived fish larvae and juveniles %U https://doi.org/10.1016/j.jmarsys.2011.09.010 %X Gaining reliable estimates of how long fish early life stages can survive without feeding and how starvation rate and time until death are influenced by body size, temperature and species is critical to understanding processes controlling mortality in the sea. The present study is an across-species analysis of starvation-induced changes in biochemical condition in early life stages of nine marine and freshwater fishes. Data were compiled on changes in body size (dry weight, DW) and biochemical condition (standardized RNA–DNA ratio, sRD) throughout the course of starvation of yolk-sac and feeding larvae and juveniles in the laboratory. In all cases, the mean biochemical condition of groups decreased exponentially with starvation time, regardless of initial condition and endogenous yolk reserves. A starvation rate for individuals was estimated from discrete 75th percentiles of sampled populations versus time (degree-days, Dd). The 10th percentile of sRD successfully approximated the lowest, life-stage-specific biochemical condition (the edge of death). Temperature could explain 59% of the variability in time to death whereas DW had no effect. Species and life-stage-specific differences in starvation parameters suggest selective adaptation to food deprivation. Previously published, interspecific functions predicting the relationship between growth rate and sRD in feeding fish larvae do not apply to individuals experiencing prolonged food deprivation. Starvation rate, edge of death, and time to death are viable proxies for the physiological processes under food deprivation of individual fish pre-recruits in the laboratory and provide useful metrics for research on the role of starvation in the sea. %0 journal article %@ 0034-4257 %A Tilstone, G.H., Peters, S.W.M., Woerd, H.J. van der, Eleveld, M.A., Ruddick, K., Schoenfeld, W., Krasemann, H., Martinez-Vicente, V., Blondeau-Patissier, D., Roettgers, R., Soerensen, K., Joergensen, P.V., Shutler, J.D. %D 2012 %J Remote Sensing of Environment %P 320-338 %R doi:10.1016/j.rse.2011.11.019 %T Variability in specific-absorption properties and their use in a semi-analytical ocean colour algorithm for MERIS in North Sea and Western English Channel Coastal Waters %U https://doi.org/10.1016/j.rse.2011.11.019 %X Coastal areas of the North Sea are commercially important for fishing and tourism, and are subject to the increasingly adverse effects of harmful algal blooms, eutrophication and climate change. Monitoring phytoplankton in these areas using Ocean Colour Remote Sensing is hampered by the high spatial and temporal variations in absorption and scattering properties. In this paper we demonstrate a clustering method based on specific-absorption properties that gives accurate water quality products from the Medium Resolution Imaging Spectrometer (MERIS). A total of 468 measurements of Chlorophyll a (Chla), Total Suspended Material (TSM), specific- (sIOP) and inherent optical properties (IOP) were measured in the North Sea between April 1999 and September 2004. Chla varied from 0.2 to 35 mg m− 3, TSM from 0.2 to 75 g m− 3 and absorption properties of coloured dissolved organic material at 442 nm (aCDOM(442)) was 0.02 to 0.26 m− 1. The variation in absorption properties of phytoplankton (aph) and non-algal particles (aNAP) were an order of magnitude greater than that for aph normalized to Chla (aph*) and aNAP normalized to TSM (aNAP*). Hierarchical cluster analysis on aph*, aNAP* and aCDOM reduced this large data set to three groups of high aNAP*–aCDOM, low aph* situated close to the coast, medium values further offshore and low aNAP*–aCDOM, high aph* in open ocean and Dutch coastal waters. The median sIOP of each cluster were used to parameterize a semi-analytical algorithm to retrieve concentrations of Chla, TSM and aCDOM(442) from MERIS data. A further 60 measurements of normalized water leaving radiance (nLw), Chla, TSM, aCDOM(442) and aNAP(442) collected between 2003 and 2006 were used to assess the accuracy of the satellite products. The regionalized MERIS algorithm showed improved performance in Chla and aCDOM(442) estimates with relative percentage differences of 29 and 8% compared to 34 and 134% for standard MERIS Chla and adg(442) products, and similar retrieval for TSM at concentrations > 1 g− 3. %0 conference lecture %@ %A Hieronymi, M., Macke, A. %D 2012 %J International Radiation Symposium 2012 %T Wave-induced irradiance variability in the upper ocean from modeling and observations %U %X %0 conference lecture %@ %A Breitbach, G., Krasemann, H. %D 2012 %J European Geosciences Union General Assembly 2012 %T Web Services as Building Blocks for an Open Coastal Observing System %U %X %0 journal article %@ %A Testor, P., Mortier, L., Karstensen, J., Mauri, E., Heywood, K., Hayes, D., Alenius, P., Alvarez, A., Barrera, C., Beguery, L., Bernardet, K., Bertino, L., Beszczynska-Moeller, A., Cerval, T., Counillon, F., Dumont, E., Griffiths, G., Haugan, P.M., Kaiser, J., Kasis, D., Krahmann, G., Llinas, O., Merckelbach, L., Mourre, B., Nittis, K., Onken, R., D`Òrtenzio, F., Pouliquen, S., Proelss, A., Rietmueller, R., Ruiz, S., Sherwin, T., Smeed, D., Stemmann, L., Tikka, K., Tintore, J. %D 2012 %J Mercator Ocean - Coriolis Quarterly Newsletter %N April %P 12-15 %T Newsletter: EGO: Towards a Global Glider Infrastructure for the Benefit of Marine Research and Operational Oceanography %U April %X The concept of underwater gliders emerged from the work of Douglas Webb in 1986. His scientist colleague Henry Stommel anticipated their development and their use. He wrote an impressive “science fiction” article which was published in Oceanography (Stommel, 1989). In look-ing back on Stommel’s article anticipating autonomous gliders, we can now marvel at how much of what followed he had predicted. In the 1990 s, while gliders were being developed and successfully passing first tests, their potential use for ocean research started to be discussed in international conferences because they could help us improve the cost-effectiveness, sampling, and distribution of the ocean observations (see OceanObs’99 Conference Statement – UNESCO). After the prototype phase, three different operational gliders (Figure 1) were present-ed by their designers in Davis et al. (2002) and applications to ocean research were highlighted in Rudnick et al. (2004). Later on, one could only witness the growing glider activity throughout the world. %0 journal article %@ 0024-3590 %A Gao, H., Matyka, M., Liu, B., Khalili, A., Kostka, J.E., Collins, G., Jansen, S., Holtappels, M., Jensen, M.M., Badewien, T.H., Beck, M., Grunwald, M., de Beer, D., Lavik, G., Kuypers, M.M.M. %D 2012 %J Limnology and Oceanography %N 1 %P 185-198 %R doi:10.4319/lo.2012.57.1.0185 %T Intensive and extensive nitrogen loss from intertidal permeable sediments of the Wadden Sea %U https://doi.org/10.4319/lo.2012.57.1.0185 1 %X Nitrogen (N) loss rates were determined in permeable sediments of the Wadden Sea using a combination of stable N isotope incubation experiments and model simulation approaches during three seasons. Three different incubation methods that employed the isotope pairing technique were used: intact core incubations simulating either (1) diffusive or (2) advective transport conditions and (3) slurry incubations. N loss rates from core incubations under simulated advective transport conditions exceeded those rates measured under diffusive transport conditions by 1-2 orders of magnitude, but were comparable to those observed in slurry incubations. N loss rates generally showed little seasonal and spatial variation (207 ± 30 µmol m-2 h-1) in autumn 2006 and spring and summer 2007. Utilizing an extensive time series of nutrient concentrations and current velocities obtained from a continuous monitoring station, nitrate and nitrite (i.e., NO−x) flux into the sediment was modeled over a full annual cycle. Fluxes were sufficient to support the experimentally derived N loss rates. Combining the measured rates with the modeled results, an annual N removal rate of 745 ± 109 mmol N m-;2 yr-1 was estimated for permeable sediments of the Wadden Sea. This rate agrees well with previous N loss estimates for the Wadden Sea based on N budget calculations. Permeable sediments, accounting for 58-70% of the continental shelf area, are an important N sink and their contribution to the global N loss budget should be reevaluated. %0 journal article %@ 2070-2000 %A Eschenbach, C. %D 2012 %J INPRINT / Land-Ocean Interactions in the Coastal Zone %P 9-15 %T Coastal Observing System for Northern and Arctic Seas: User interactions in COSYNA %U %X For the purpose of supporting decision-making processes COSYNA develops highly sophisticated scientific methods to describe the state of the North Sea ecosystems. COSYNA products range from time series at various locations and regular maps of e.g. currents, waves, salinity, temperature, chlorophyll, oxygen, etc., to routine short-term forecasts (days) for these parameters. With these products COSYNA aims to reduce the gap between operational oceanography and the various users of data and forecasts of the state of the North Sea. In order to ensure products are applicable, a two-way information flow was initiated where the users themselves can provide feedback and input to COSYNA. The most relevant phases for user interaction are the release of a product idea and product implementation. Potential users include authorities, associations (nature conservation, tourism), science, and industry (e.g. renewable energy companies). During COSYNA’s early stages a survey on user requirements identified six parameters to be most useful to the greatest number of users. These are meteorological data, current, waves, bathymetry, turbidity and water temperature. High demand was revealed for forecasts and simulations (81 %), oceanographic modelling data (76%), meteorological modelling data, reconstructions of storm surges, waves, water level, and mathematical modelling of habitats. Past user interactions, such as workshops and external evaluation of the first integrated product “Pre-operational Surface Current Fields” have clearly improved COSYNA products and their usability. In order to reach the general public COSYNA publishes brochures, flyers, fact sheets and newsletters in German and English among other activities. The communication & interaction concept aims at strengthening the status of COSYNA in the various user groups and with the general public. It needs to be constantly adapted to new developments and changing framework conditions. %0 book part %@ %A Flampouris, S., Seemann, J., Senet, C., Ziemer, F. %D 2012 %J Multiscale Hydrologic Remote Sensing: Perspectives and Applications %P 33-64 %R doi:10.1201/b11279-5 %T Storm Impact on the Coastal Geomorphology and Current Field by Wave Field Image sequences %U https://doi.org/10.1201/b11279-5 %X In this study, the DiSC methodology is summarized; the post processing approaches and their consistency with echo soundings are presented. The main focus of this study is the demonstration of the method’s capabilities into the frame of a coastal monitoring system of a sand-barrier island which is continuously under eroding pressure. The method is illustrated by focusing on the monitoring of the impact of a 10-day storm on the current field and bathymetry at the littoral zone of the island Sylt in German Bight. The total volume of the moved sediment, within the 5 km2 monitored area for the 10 days period, is estimated in the order of 5 % of the annual sediment budget of the area. The tidal current field was monitored for 3 tidal cycles during which the impacts of the local geomorphology, of the air pressure and of the wind could be identified. The low air pressure eliminated the ebb phase of the current field. The measurements in front of the entrance of the tidal basin proofed the atmospheric pressure gradient has a direct impact on the local current field and dominates the local circulation. In general, the present study illustrates the potential of the ground based remote sensing in monitoring of small-area changes in the coastal environment caused by mesoscale phenomena. %0 journal article %@ 0272-7714 %A Kowalski, N., Dellwig, O., Beck, M., Grunwald, M., Duerselen, C.-D., Badewien, T.H., Brumsack, H.-J., Beusekom, J.E.E.van, Boettcher, M.E. %D 2012 %J Estuarine, Coastal and Shelf Science %P 3-17 %R doi:10.1016/j.ecss.2011.03.011 %T A comparative study of manganese dynamics in the water column and sediments of intertidal systems of the North Sea %U https://doi.org/10.1016/j.ecss.2011.03.011 %X Site-specific differences are also seen in further tidal systems of the North Frisian Wadden Sea, which are characterised by individual hydrodynamical and sedimentological conditions. Several transects leading from offshore locations towards the coast also revealed a highly variable Mn level. Overall, the North Frisian Wadden Sea most likely represents a less important source for dissolved Mn than the East Frisian Wadden Sea. Furthermore, our data suggest that site-specific properties of the different tidal basins have to be considered in budget calculations for the entire Wadden Sea. %0 journal article %@ 1812-0784 %A Hieronymi, M., Macke, A. %D 2012 %J Ocean Science %N 4 %P 455-471 %R doi:10.5194/os-8-455-2012 %T On the influence of wind and waves on underwater irradiance fluctuations %U https://doi.org/10.5194/os-8-455-2012 4 %X The influence of various wind and wave conditions on the variability of downwelling irradiance Ed (490 nm) in water is subject of this study. The work is based on a two-dimensional Monte Carlo radiative transfer model with high spatial resolution. The model assumes conditions that are ideal for wave focusing, thus simulation results reveal the upper limit for light fluctuations. Local wind primarily determines the steepness of capillary-gravity waves which in turn dominate the irradiance variability near the surface. Down to 3 m depth, maximum irradiance peaks that exceed the mean irradiance Ed by a factor of more than 7 can be observed at low wind speeds up to 5 m s−1. The strength of irradiance fluctuations can be even amplified under the influence of higher ultra-gravity waves; thereby peaks can exceed 11 Ed. Sea states influence the light field much deeper; gravity waves can cause considerable irradiance variability even at 100 m depth. The simulation results show that under realistic conditions 50% radiative enhancements compared to the mean can still occur at 30 m depth. At greater depths, the underwater light variability depends on the wave steepness of the characteristic wave of a sea state; steeper waves cause stronger light fluctuations. %0 book part %@ %A Garrett, C., Baschek, B., Gemmrich, J. %D 2012 %J McGraw-Hill Yearbook of Science and Technology %P 229-231 %T Rogue Waves %U %X “Rogue wave” is a popular term for an unusually large ocean wave that can cause damage to ships or endanger people. There are three issues to be discussed. First, some media accounts of rogue waves really just refer to very rough seas. Second, for the scientist, the term rogue wave refers to waves that are larger than the average in a particular sea state by a specified multiplier. The third issue is the most interesting: In a given sea state, do these large, rare, rogue waves occur more frequently than expected from standard dynamical or statistical models? An alternative version of this question is: Do waves that are larger than the average by a particular multiple occur more frequently than predicted? We examine each of these issues, along with further questions that arise. %0 HZG report %@ 2191-7833 %A Cysewski, M.C. %D 2011 %J %T Charakterisierung von Strukturen im Stroemungsfeld gemessen mit einem Acoustic Doppler Current Profiler (Masterarbeit) %U %X %0 journal article %@ 1812-0784 %A Assmann, S., Frank, C., Koertzinger, A. %D 2011 %J Ocean Science %N 5 %P 597-607 %R doi:10.5194/os-7-597-2011 %T Spectrophotometric high-precision seawater pH determination for use in underway measuring systems %U https://doi.org/10.5194/os-7-597-2011 5 %X Autonomous sensors are required for a comprehensive documentation of the changes in the marine carbon system and thus to differentiate between its natural variability and anthropogenic impacts. Spectrophotometric determination of pH – a key variable of the seawater carbon system – is particularly suited to achieve precise and drift-free measurements. However, available spectrophotometric instruments are not suitable for integration into automated measurement systems (e.g. FerryBox) since they do not meet the major requirements of reliability, stability, robustness and moderate cost. Here we report on the development and testing of a~new indicator-based pH sensor that meets all of these requirements. This sensor can withstand the rough conditions during long-term deployments on ships of opportunity and is applicable to the open ocean as well as to coastal waters with a complex matrix and highly variable conditions. The sensor uses a high resolution CCD spectrometer as detector connected via optical fibers to a custom-made cuvette designed to reduce the impact of air bubbles. The sample temperature can be precisely adjusted (25 °C ± 0.006 °C) using computer-controlled power supplies and Peltier elements thus avoiding the widely used water bath. The overall setup achieves a measurement frequency of 1 min−1 with a precision of ±0.0007 pH units, an average offset of +0.0005 pH units to a reference system, and an offset of +0.0081 pH units to a certified standard buffer. Application of this sensor allows monitoring of seawater pH in autonomous underway systems, providing a key variable for characterization and understanding of the marine carbon system. %0 journal article %@ %A Willis, J., Merckelbach, L. %D 2011 %J Nature Precedings %R doi:10.1038/npre.2011.6564.1 %T Levy flight is not evolved behavior %U https://doi.org/10.1038/npre.2011.6564.1 %X Tracks of moving animals have many short moves interspersed with longer moves, and frequencies of all moves together often indicate Levy flights (a type of power law)1. The Levy flight foraging hypothesis suggests that, ‘since Levy flights and walks can optimize search efficiencies, therefore natural selection should have led to adaptations for Levy flight foraging1 and it has been apparently supported by several studies of large numbers of tracks of marine animals234. We show that Levy flights are caused by marine animals attempting to move in simple ways and they are unlikely to be evolved behavior. We do this by analyzing the tracks of autonomous underwater gliders which conform to Levy flights while they were programmed to perform simple directed movement. Gliders are autonomous underwater vehicles (AUV), propelled by a buoyancy engine5.The principle of operation is that by alternating positive and negative buoyancy, the winged AUV glides through the ocean in an undulating path, resurfacing after a pre-programmed number of undulations. During the periods at the surface, which typically last 15 minutes, GPS is used for positioning before and after transmission of data via a satellite link, whereas underwater the trajectory is deadreckoned from measured heading, pitch and pressure rate. Thus they are potentially a good analogy to a navigating animal which may also attempt to make directed movements using the best available (and often intermittent6) navigational information. %0 journal article %@ 1616-7341 %A Petersen, W., Schroeder, F., Bockelmann, F.-D. %D 2011 %J Ocean Dynamics %N 10 %P 1541-1554 %R doi:10.1007/s10236-011-0445-0 %T FerryBox - Application of continuous water quality observations along transects in the North Sea %U https://doi.org/10.1007/s10236-011-0445-0 10 %X In 2002, the Helmholtz-Zentrum Geesthacht, Germany, started to use FerryBox-automated monitoring systems on Ships of Opportunity to continuously record standard oceanographic, biological and chemical in situ data in the North Sea. The present study summarises the operational experience gathered since the beginning of this deployment and reflects on the potential and limits of FerryBox systems as a monitoring tool. One part relates to the instrumental performance, constancy of shipping services, and the availability and quality of the recorded in situ data. The other considers integration of the FerryBox observations in scientific applications and routine monitoring campaigns. Examples are presented that highlight the added value of the recorded data for the study of both long- and short-term variability in water mass stability, plankton communities and surface water productivity in the North Sea. Through the assessment of technical and scientific performance, it is evident that FerryBoxes have become a valuable tool in marine research that helps to fill gaps in coastal and open ocean operational observation networks. %0 journal article %@ 0739-0572 %A Aiken, C.M., Petersen, W., Schroeder, F., Gehrung, M., Ramirez von Holle, P. %D 2011 %J Journal of Atmospheric and Oceanic Technology %N 10 %P 1338-1350 %R doi:10.1175/JTECH-D-10-05022.1 %T Ship-of-Opportunity Monitoring of the Chilean Fjords Using the Pocket FerryBox %U https://doi.org/10.1175/JTECH-D-10-05022.1 10 %X Results from two field campaigns in the Chilean fjords region are presented to demonstrate the benefits and limitations of the “pocket FerryBox” for monitoring from ships of opportunity. The October 2009 (spring) campaign covered the region of the Chilean coast between 41.5° and 46.7°S, and that in March 2010 (autumn) covered the region between 41.5° and 51.8°S. In the campaigns the pocket FerryBox—a portable flow-through system for underway multiparametric monitoring—was installed temporarily on board the vessel M/V Ro-Ro Evangelistas. The taking of water samples allowed posterior calibration of the sensors and analyses for nutrients and plankton. The pocket FerryBox may be configured with multiple sensors [in this case temperature, salinity, dissolved oxygen, chlorophyll-a fluorescence, pH, turbidity, and colored dissolved organic matter (CDOM)] and includes the hardware and software for data acquisition and real-time presentation. In the Chilean campaigns multiple transects of up to 1700 km in length were obtained, which provided a unique and highly valuable dataset at a very low cost. The data uncovered a number of previously unreported results, including a tidally driven low dissolved oxygen zone in the Corcovado Gulf, a high level of spatial and temporal variability of, and a complex relationship between, dissolved oxygen and chlorophyll-a fluorescence, and the detection of high concentrations of CDOM in the vicinity of the Laguna San Rafael. The campaigns confirm that the pocket FerryBox may be easily installed on board ships of opportunity to obtain rapid, low-cost, and spatially extensive surveys of highly relevant surface water properties. %0 journal article %@ 0094-8276 %A Becherer, J., Burchard, H., Floeser, G., Mohrholz, V., Umlauf, L. %D 2011 %J Geophysical Research Letters %P 17611 %R doi:10.1029/2011GL049005 %T Evidence of tidal straining in well-mixed channel flow from micro-structure observations %U https://doi.org/10.1029/2011GL049005 %X This study presents, for the first time, micro-structure observations in tidally energetic, weakly stratified regimes obtained in the Wadden Sea, a tidal shallow coastal area in the South-Eastern North Sea characterised by barrier islands separated by tidal gulleys. The tidal currents are typically overlaid by a weak horizontal density gradient due to freshwater run-off from land. The observations in an energetic tidal channel clearly show the expected effects of tidal straining: destratification during flood and increased stratification during ebb. Microstructure observations are consistent with the tidal straining dynamics: during the flood relatively high values of viscous dissipation are observed whilst during ebb the values are substantially smaller. It is also shown that the tidal cycle of stratification and destratification depends on the position in the tidal channel. In parts of the channel, increased stratification occurs during full flood, a phenomenon which can only be explained by advection of stratified water masses formed outside the tidal channel. The observations presented here show the general significance of the tidal straining process for tidally energetic weakly stratified regimes. %0 journal article %@ 1726-4170 %A Taylor, B.B., Torrecilla, E., Bernhardt, A., Taylor, M.H., Peeken, I., Röttgers, R., Piera, J., Bracher, A. %D 2011 %J Biogeosciences %N 12 %P 3609-3629 %R doi:10.5194/bg-8-3609-2011 %T Bio-optical provinces in the eastern Atlantic Ocean and their biogeographical relevance %U https://doi.org/10.5194/bg-8-3609-2011 12 %X The relationship between phytoplankton assemblages and the associated optical properties of the water body is important for the further development of algorithms for large-scale remote sensing of phytoplankton biomass and the identification of phytoplankton functional types (PFTs), which are often representative for different biogeochemical export scenarios. Optical in-situ measurements aid in the identification of phytoplankton groups with differing pigment compositions and are widely used to validate remote sensing data. In this study we present results from an interdisciplinary cruise aboard the RV Polarstern along a north-to-south transect in the eastern Atlantic Ocean in November 2008. Phytoplankton community composition was identified using a broad set of in-situ measurements. Water samples from the surface and the depth of maximum chlorophyll concentration were analyzed by high performance liquid chromatography (HPLC), flow cytometry, spectrophotometry and microscopy. Simultaneously, the above- and underwater light field was measured by a set of high spectral resolution (hyperspectral) radiometers. An unsupervised cluster algorithm applied to the measured parameters allowed us to define bio-optical provinces, which we compared to ecological provinces proposed elsewhere in the literature. As could be expected, picophytoplankton was responsible for most of the variability of PFTs in the eastern Atlantic Ocean. Our bio-optical clusters agreed well with established provinces and thus can be used to classify areas of similar biogeography. This method has the potential to become an automated approach where satellite data could be used to identify shifting boundaries of established ecological provinces or to track exceptions from the rule to improve our understanding of the biogeochemical cycles in the ocean. %0 conference lecture (invited) %@ %A Colijn, F. %D 2011 %J INTERCOAST Workshop %T COSYNA %U %X %0 conference lecture %@ %A Riethmueller, R., Colijn, F., Doerffer, R., Floeser, G., Petersen, W., Philippart, K., Schartau, M., Wirtz, K., Ziemer, F. %D 2011 %J International Symposium on the Ecology of the Wadden Sea %T New conceptual insights through high frequency observations: Covering temporal and spatial scales %U %X %0 conference paper %@ %A Wirtz, K.W., Schroeder, F. %D 2011 %J Book of Abstracts, 5th International Short Conference on Applied Coastal Research, SCACR 2011 %P 67-68 %T The integrated coastal observation and model system COSYNA %U %X %0 conference lecture %@ %A Wirtz, K.W., Schroeder, F. %D 2011 %J 5th International Short Conference on Applied Coastal Research, SCACR 2011 %T The integrated coastal observation and model system COSYNA %U %X %0 conference lecture %@ %A Breitbach, G., Krasemann, H. %D 2011 %J Workshop Marine Daten-Infrastruktur Deutschland %T Datenmanagement in COSYNA %U %X %0 conference lecture %@ %A Colijn, F., Petersen, W., Schroeder, F. %D 2011 %J FerryBoxes as Part of Operational Observation Networks: Monitoring versus Scientific Aspects, 4th FerryBox Workshop 2011 %T FerryBox: State-of-the-art and future incorporation in an European observational network %U %X %0 conference poster %@ %A Riethmueller, R., Onken, R., Rinck, H., Thomas, H., Kopetzky, R. %D 2011 %J The Future of Operational Oceanography, FutOOre 2011 %T ScanFish Observations in the Shallow Waters of the German Bight %U %X %0 conference lecture %@ %A Merckelbach, L., Werner, A., Kopetzky, R., Peters, B., Onken, R. %D 2011 %J The Future of Operational Oceanography, FutOOre 2011 %T First-time deployment of gliders in the German Bight %U %X %0 conference paper %@ %A Breitbach, G., Krasemann, H. %D 2011 %J Innovations in Sharing Environmental Observations and Information, Proceedings of the 25th International Conference on Environmental Informatics, EnviroInfo 2011 %P 933-940 %T Data Management in the Coastal Observing System COSYNA %U %X %0 conference lecture %@ %A Breitbach, G., Krasemann, H. %D 2011 %J 25th International Conference on Environmental Informatics, EnviroInfo 2011 %T Data Management in the Coastal Observing System COSYNA %U %X %0 conference lecture (invited) %@ %A Colijn, F. %D 2011 %J 5th Meeting of the Expert Group of Marine Research Infrastructure %T Ferry Boxes - Vessels of opportunity %U %X %0 conference lecture %@ %A Colijn, F. %D 2011 %J Meeting ICES Working Group on Integrated Assessments of the North Sea %T COSYNA %U %X %0 book part %@ %A Colijn, F., Fanger, H.-U. %D 2011 %J Klimabericht fuer die Metropolregion Hamburg %P 177-194 %R doi:10.1007/978-3-642-16035-6 %T Klimabedingte Aenderungen in aquatischen Oekosystemen: Elbe, Wattenmeer und Nordsee %U https://doi.org/10.1007/978-3-642-16035-6 %X Unterschiedliche Aussagen finden sich zur Sedimentation und Flächenänderungen von Vordeichs- und Wattgebieten und damit zur Gefährdung von Tideauenwäldern. %0 journal article %@ 1094-4087 %A Ebata, H., Tanaka, A., Takahashi, Y., Yano, S., Tan, H., Doerffer, R., Oishi, T. %D 2011 %J Optics Express %N 11 %P 10063-10072 %R doi:10.1364/OE.19.010063 %T Simultaneous illumination method: application in a two-channel emission fluorometer with multi-wavelength excitation %U https://doi.org/10.1364/OE.19.010063 11 %X We developed a new illumination method called the simultaneous illumination method. This method does not require synchronization between light sources and sensor signals, which drastically simplifies the instrumentation. As a proof-of-concept, we applied this method to an oceanographic fluorometer. In principle, using this method, one can easily increase the number of characterized emission wavelengths by mounting optical sensors for as many emission wavelengths as needed. Our fluorometer has two emission-wavelength channels and twelve excitation wavelengths. The aim of this prototype is to demonstrate a viable in situ N-channel emission fluorometer with multiple wavelengths of excitation, which has not been previously realized. %0 journal article %@ 0142-7873 %A Hamer, H., Malzahn, A., Boersma, M. %D 2011 %J Journal of Plankton Research %N 1 %P 137-144 %R doi:10.1093/plankt/fbq100 %T The invasive ctenophore Mnemiopsis leidyi: a threat to fish recruitment in the North Sea? %U https://doi.org/10.1093/plankt/fbq100 1 %X The invasive ctenophore Mnemiopsis leidyi has a strong reputation as a threat to fish stocks. Apart from competitive relationships between M. leidyi and fish larvae, direct predation by the ctenophore on both eggs and larvae is considered an important factor linking ctenophore and fish populations. We therefore estimated abundances of both the ctenophore and its potential prey in the spring of 2008. No significant correlations were detected between ctenophore numbers and the abundance of fish eggs. We further carried out stable isotope analyses to investigate the trophic position of M. leidyi. Carbon and nitrogen stable isotope signatures of three potential prey groups (fish eggs, small plankton and larger plankton) showed that M. leidyi primarily feeds on plankton, while fish eggs are of minor importance. Mnemiopsis leidyi was located roughly one trophic level above the indigenous ctenophore Bolinopsis infundibulum, whereas its trophic position was more similar to another native ctenophore, Pleurobrachia pileus. A feeding selection experiment, with fish eggs and copepods offered in the same proportion, corroborated these findings. Mnemiopsis leidyi ingested significantly more copepods; feeding on fish eggs was not significantly different from zero. Based on these experiments, we conclude that in the North Sea, M. leidyi has no serious potential as a direct predator of fish eggs, but individuals of this species might compete for food with larval fish as well as with the native ctenophore P. pileus. %0 journal article %@ 1812-0784 %A Stanev, E. V., Schulz-Stellenfleth, J., Staneva, J., Grayek, S., Seemann, J., Petersen, W. %D 2011 %J Ocean Science %N 5 %P 569-583 %R doi:10.5194/os-7-569-2011 %T Coastal observing and forecasting system for the German Bight – estimates of hydrophysical states %U https://doi.org/10.5194/os-7-569-2011 5 %X A coastal observing system for Northern and Arctic Seas (COSYNA) aims at construction of a long-term observatory for the German part of the North Sea, elements of which will be deployed as prototype modules in Arctic coastal waters. At present a coastal prediction system deployed in the area of the German Bight integrates near real-time measurements with numerical models in a pre-operational way and provides continuously state estimates and forecasts of coastal ocean state. The measurement suite contributing to the pre-operational set up includes in situ time series from stationary stations, a High-Frequency (HF) radar system measuring surface currents, a FerryBox system and remote sensing data from satellites. The forecasting suite includes nested 3-D hydrodynamic models running in a data-assimilation mode, which are forced with up-to-date meteorological forecast data. This paper reviews the present status of the system and its recent upgrades focusing on developments in the field of coastal data assimilation. Model supported data analysis and state estimates are illustrated using HF radar and FerryBox observations as examples. A new method combining radial surface current measurements from a single HF radar with a priori information from a hydrodynamic model is presented, which optimally relates tidal ellipses parameters of the 2-D current field and the M2 phase and magnitude of the radials. The method presents a robust and helpful first step towards the implementation of a more sophisticated assimilation system and demonstrates that even using only radials from one station can substantially benefit state estimates for surface currents. Assimilation of FerryBox data based on an optimal interpolation approach using a Kalman filter with a stationary background covariance matrix derived from a preliminary model run which was validated against remote sensing and in situ data demonstrated the capabilities of the pre-operational system. Data assimilation significantly improved the performance of the model with respect to both SST and SSS and demonstrated a good skill not only in the vicinity of the Ferry track, but also over larger model areas. The examples provided in this study are considered as initial steps in establishing new coastal ocean products enhanced by the integrated COSYNA-observations and numerical modelling. %0 journal article %@ 1545-598X %A Flampouris, S., Seemann, J., Senet, C., Ziemer, F. %D 2011 %J IEEE Geoscience and Remote Sensing Letters %N 4 %P 436-440 %R doi:10.1109/LGRS.2010.2082491 %T The Influence of the Inverted Sea Wave Theories on the Derivation of Coastal Bathymetry %U https://doi.org/10.1109/LGRS.2010.2082491 4 %X The estimation of nearshore bathymetry by inverting the wave dispersion function is an accepted method. The performance of four different wave theories inverted with dispersive surface classificator for the derivation of the bathymetry is examined during gale oceanographic conditions. The physical and technical limitations for the inversion are taken into consideration. The analyzed data are radar image sequences, and ground truth is an in situ echosounder's bathymetry data set. All geomorphological features detectable with a 41-m spatial resolution have been identified, but there is an underestimation of the absolute depth. The applicable theories have mean error less than 7%. The nonlinear theories are compared with the linear theory, and the experimental difference of their performance is on the order of the theoretical expectation $O$ (6%–8%). %0 conference poster %@ %A Boldreel, L.O., Kuijpers, A., Riethmueller, R., Heineke, M., Seemann, J., Hass, C., Lindhorst, S., Rasmussen, R., Bartholdy, J., Pedersena, J.B.T. %D 2011 %J 16. Danske Havforskermoede %T Sedimentary regime of the ‘Lister Tief’ between Sylt and Rømø, South-eastern North Sea, based on shallow seismic subbottom profiles and Multibeam data %U %X %0 journal article %@ 0278-4343 %A Onken, R., Riethmueller, R. %D 2010 %J Continental Shelf Research %N 8 %P 924-933 %R doi:10.1016/j.csr.2010.02.004 %T Determination of the freshwater budget of tidal flats from measurements near a tidal inlet %U https://doi.org/10.1016/j.csr.2010.02.004 8 %X The freshwater budget of a tidal flat area is evaluated from long-term hydrographic time series from an observation pole positioned in a tidal channel in the Hörnum Basin (Germany). For each tidal cycle, the freshwater budget is calculated from the total imported and exported water volumes and the corresponding mean densities. The variability of the budget on a tidal scale is characterised by a period of twice the tidal period, exhibiting a minimum when the tidal flats are dry around daylight hours during the foregoing low tide, and a maximum when low tide occurs at night; enhanced evaporation on the flats at daylight hours is identified as the driving process. On the average over one year, while winter observations are missing, the freshwater budget is negative for the years 2002-2005 and positive only for 2006. The interannual mean is negative and amounts to a freshwater loss of about 2 mm/day, although the large-scale climate in this region is humid. The results demonstrate that the bulk parametrisations for the latent and sensible heat flux between the ocean and the atmosphere must not be applied for the tidelands. %0 journal article %@ 1674-487X %A Frank, C., Schroeder, F., Petersen, W. %D 2010 %J Journal of Earth Science %N 6 %P 861-869 %R doi:10.1007/s12583-010-0138-5 %T FerryBox: Using Automated Water Measurement Systems to Monitor Water Quality: Perspectives for the Yangtze River and Three Gorges Dam %U https://doi.org/10.1007/s12583-010-0138-5 6 %X Therefore, a concept of applying regular automated observations by a FerryBox is presented. It is shown that such systems are very well suited to give feedback for the assessment of measures to improve the water quality. %0 journal article %@ 0025-3227 %A Buerk, D., Klaucke, I., Sahling, H., Weinrebe, W. %D 2010 %J Marine Geology %N 1-4 %P 53-65 %R doi:10.1016/j.margeo.2010.04.007 %T Morpho-acoustic variability of cold seeps on the continental slope offshore Nicaragua: Result of fluid flow interaction with sedimentary processes %U https://doi.org/10.1016/j.margeo.2010.04.007 1-4 %X Based on multibeam bathymetry, high-resolution deep-towed sidescan sonar and Chirp subbottom profiling 32 cold seep sites, already identified in Sahling et al. (2008a), have been studied in an approximately 1000 km2 large area ranging from 800 to 2600 m water depth along the middle slope of the active continental margin offshore Nicaragua. Ground truthing is available from towed camera surveys and coring on seven of the structures. The seeps occur in different settings on the slope: upslope and along the headwall of large submarine slides, as isolated eroded massifs, and forming linear ridges between deeply incised canyons. The seep sites show a wide range regarding their size and morphology, their backscatter intensity patterns, their structure in subbottom profiles, and their fluid venting activity inferred from seafloor observations. Surface extension of the seep sites ranges from less than 200 to more than 1500 m in diameter, and relief height varies between no relief and 180 m. Indications of extruded materials such as mud flows are not observed in the area of the seep sites. Instead the seeps are characterized by high proportions of authigenic carbonates. The carbonates occur as crusts, detritus, or single layers embedded in the seafloor sediments. They appear as high backscatter intensities on sidescan sonar images. On some seep sites living vent fauna indicative of active seepage is observed, but gas bubbles have not been observed. To explain the high morphological variability of the features, we propose a generic model including the interaction of several processes: (1) episodic fluid venting and associated authigenic carbonate formation; (2) background sedimentation and subsidence; (3) linear erosion along canyons and denudation on the slope surface. %0 conference lecture %@ %A Flampouris, S., Seemann, J., Ziemer, F. %D 2010 %J 2010 Ocean Sciences Meeting %T Observation of littoral hydrodynamics by ground based Dopplerized X-band Radar %U %X %0 journal article %@ 0148-0227 %A Signell, R., Chiggiato, J., Horstmann, J., Doyle, J., Pullen, J., Askari, F. %D 2010 %J Journal of Geophysical Research : Oceans %N C 4 %P 04020 %R doi:10.1029/2009JC005524 %T High-Resolution mapping of Bora winds in the Northern Adriatic Sea using synthetic aperture radar %U https://doi.org/10.1029/2009JC005524 C 4 %X barrier jet, forming along the Italian Apennine mountain chain. %0 conference lecture %@ %A Breitbach, G., Krasemann, H., Onken, R. %D 2010 %J International Conference on Marine Data and Information Systems, IMDIS 2010 %T Data Management in COSYNA %U %X %0 conference lecture %@ %A Schartau, M., Colijn, F., Engel, A., Gerdts, G., Metfies, K., Moll, A., Schlueter, M. %D 2010 %J ICES-WGPME Annual Meeting 2010 %T Towards an integrative approach in phytoplankton and microbial ecology %U %X %0 conference poster %@ %A Winde, V., Schutz, M., Escher, P., Dellwig, O., Beusekom, J.van, Schwichtenberg, F., Paetsch, J., Schartau, M., Thomas, H., Schneide, B., Kowalski, N., Boening, P., Knoeller, K., Liebezeit, G., Boettcher, M. %D 2010 %J 1st Joint Meeting Coordinated Projects, EPOCA (European Project on Ocean Acidification), the German project BIOACID (Biological Impacts of Ocean ACIDification) and UK project UKOARP (UK Ocean Acidification Research Program). %T Dynamics of the benthic and pelagic dissolved inorganic carbonate systems, and the stability of benthic carbonates in tidal areas of the North Sea: First results of field and experimental approaches %U %X %0 journal article %@ 0948-4280 %A Onken, R., Garbe, H., Schroeder, S., Janik, M. %D 2010 %J Journal of Marine Science and Technology %N 4 %P 427-433 %R doi:10.1007/s00773-010-0096-8 %T A new instrument for sediment temperature measurements %U https://doi.org/10.1007/s00773-010-0096-8 4 %X A novel self-contained probe is presented which measures the sediment temperature of tidal flats between the surface and 40-cm depth, and indicates whether the flats are flooded or dry. Depending on the selected acquisition interval, the endurance of the probe is more than 6 months. It can be applied for the investigation of thermodynamic properties of the tidal flats impacting physical and biological processes. Intensive tests have shown that the probe is robust and reliable and can be easily operated by a single person. In case of rough weather conditions, the usage of scour protectors is recommended. %0 journal article %@ 1354-1013 %A Schlueter, M.H., Merico, A., Reginatto, M., Boersma, M., Wiltshire, K.H., Greve, W. %D 2010 %J Global Change Biology %N 11 %P 3144-3153 %R doi:10.1111/j.1365-2486.2010.02246.x %T Phenological shifts of three interacting zooplankton groups in relation to climate change %U https://doi.org/10.1111/j.1365-2486.2010.02246.x 11 %X Over the past several decades, global warming has been linked to shifts in the distributions and abundances of species. In the southern North Sea, temperatures have increased in the last three decades and this will likely have consequences on the seasonality of marine organisms living in the area. Ctenophores such as Beroe gracilis and Pleurobrachia pileus could be particularly affected by changes in their own phenology and that of their prey, thus causing shifts in ecosystem function. Despite their global relevance and their potentially deleterious effect on the fishing industry, only a few long-term records of ctenophore abundance exist, and most of these records are semiquantitative in nature. Therefore, our knowledge of the influence of environmental factors on their population development is presently very limited. In this study, the long-term abundance dynamics of B. gracilis, P. pileus and their food calanoid copepods were analysed for a highly temporally resolved time series in the German Bight at Helgoland Roads. Special attention was focused on the response of these organisms to climate warming. Bayesian statistics showed that the phenology of the two ctenophores shifted in a step-like mode in the year 1987/1988 to permanent earlier appearances. The seasonal change in the population blooms of P. pileus and B. gracilis correlated remarkably well with a step-like increase in winter and spring sea surface temperatures of the southern North Sea. Possible explanations for the changes observed in these organisms include higher reproductive rates, increased winter survival rates or both. Interannual variations in ctenophore abundances correlated best with the interannual changes in spring temperatures, although the impact of temperature on B. gracilis appeared less pronounced. The changes in copepods abundance were not consistent with changes in P. pileus and B. gracilis. P. pileus showed longer periods of high abundance after the permanent seasonal advancement. These longer periods were correlated with a decline in the average autumn abundance of copepods. Changes in the phenology of these organisms raise the concerns on the declining state of fish stocks, which could potentially be exacerbated by gelatinous zooplankton outbreaks. These conditions may ultimately lead to trophic dead ends by channelling the flow of energy away from higher trophic levels. %0 conference lecture (invited) %@ %A Colijn, F., Riethmueller, R., Schroeder, F., Stanev, E. %D 2010 %J Tag der Meere 2010 %T COSYNA (Coastal Observing System for Northern and Arctic Seas) - Ein "Community System" zur Beobachtung und Modellierung der Nordsee %U %X %0 journal article %@ 1559-2723 %A Wiltshire, K.H., Kraberg, A., Bartsch, I., Boersma, M., Franke, H.-D., Freund, J., Gebuehr, C., Gerdts, G., Stockmann, K., Wichels, A. %D 2010 %J Estuaries and Coasts %N 2 %P 295-310 %R doi:10.1007/s12237-009-9228-y %T Helgoland Roads, North Sea: 45 Years of Change %U https://doi.org/10.1007/s12237-009-9228-y 2 %X The Helgoland Roads time series is one of the richest temporal marine data sets available. Running since 1962, it documents changes for phytoplankton, salinity, Secchi disc depths and macronutrients. Uniquely, the data have been carefully quality controlled and linked to relevant meta-data, and the pelagic time series is further augmented by zooplankton, intertidal macroalgae, macro-zoobenthos and bacterioplankton data. Data analyses have shown changes in hydrography and biota around Helgoland. In the late 1970s, water inflows from the south-west to the German Bight increased with a corresponding increase in flushing rates. Salinity and annual mean temperature have also increased since 1962 and the latter by an average of 1.67°C. This has influenced seasonal phytoplankton growth causing significant shifts in diatom densities and the numbers of large diatoms (e. g. Coscinodiscus wailesii). Changes in zooplankton diversity have included the appearance of the ctenophore Mnemiopsis leidyi. The macroalgal community also showed an increase in green algal and a decrease in brown algal species after 1959. Over 30 benthic macrofaunal species have been newly recorded at Helgoland over the last 20 years, with a distinct shift towards southern species. These detailed data provide the basis for long-term analyses of changes on many trophic levels at Helgoland Roads. %0 journal article %@ 1385-1101 %A Grunwald, M., Dellwig, O., Kohlmeier, C., Badewien, T.H., Beck, M., Kotzur, S., Kowalski, N., Liebezeit, G., Brumsack, H.-J. %D 2010 %J Journal of Sea Research %N 3 %P 199-212 %R doi:10.1016/j.seares.2010.02.008 %T Nutrient dynamics in a back barrier tidal basin of the Southern North Sea: Time-series, model simulations, and budget estimates %U https://doi.org/10.1016/j.seares.2010.02.008 3 %X In the tidal inlet of the back barrier area of Spiekeroog Island (Southern North Sea), nutrient concentrations (silica, phosphate, ∑ nitrite + nitrate) were determined hourly by an autonomously analysing system on a permanently installed time-series station from April 2006 to December 2008. Based on the high frequency of analyses we studied nutrient dynamics on annual, seasonal, and tidal time scales. By comparing the nutrient input to the tidal flat area via freshwater through a flood-gate and pore water discharge from tidal flat sediments, we conclude that nutrients are primarily supplied to the water column by pore water advection, while the freshwater contribution is negligible. To assess the annual nutrient contribution of our study area to the German Bight, we used a numerical Euler-Lagrangian model (EcoTiM) to calculate annual budgets of silica and phosphate. The model results indicate that the back barrier area of Spiekeroog Island exports inorganic silica (128*106 mol a-1), phosphate (3*106 mol a-1), and nitrite plus nitrate (29*106 mol a-1) to the North Sea. Extrapolation of these data to the entire Wadden Sea along the southern North Sea reveals that the back barrier areas export silica and phosphate in the same order of magnitude and nitrite plus nitrate one order of magnitude lower than the combined rivers Elbe, Weser, and Ems. %0 conference lecture %@ %A Riethmueller, R., Floeser, G., Burchard, H., Mohrholz, V., Onken, R. %D 2010 %J The Wadden Sea: Changes and Challenges in a World Heritage Site, ECSA Symposium 46 %T Density driven circulation as a mean of sustained suspended sediment import into the Wadden Sea %U %X %0 conference poster %@ %A Schwichtenberg, F., Paetsch, J., Schartau, M., Thomas, H., Winde, V., Schutz, M., Dellwig, O., Beusekom, J.van, Liebezeit, G., Boettcher, M. %D 2010 %J 1st Joint Meeting Coordinated Projects, EPOCA (European Project on Ocean Acidification), the German project BIOACID (Biological Impacts of Ocean ACIDification) and UK project UKOARP (UK Ocean Acidification Research Program). %T Impact of Alkalinity flux from the Wadden Sea - First approaches of carbonate dissolution on the shelf %U %X %0 journal article %@ 0921-8971 %A Diercks, S., Gescher, C., Metfies, K., Medlin, L. %D 2010 %J Journal of Applied Phycology %P 813 %R doi:10.1007/s10811-010-9612-9 %T Erratum to: Evaluation of locked nucleic acids for signal enhancement of oligonucleotide probes for microalgae immobilised on solid surfaces %U https://doi.org/10.1007/s10811-010-9612-9 %X %0 journal article %@ 0280-6495 %A Bruemmer, B., Mueller, G., Klepp, C., Spreen, G., Romeister, R., Horstmann, J. %D 2010 %J Tellus A %N 4 %P 481-496 %R doi:10.1111/j.1600-0870.2010.00448.x %T Characteristics and impact of a gale-force storm field over the Norwegian Sea %U https://doi.org/10.1111/j.1600-0870.2010.00448.x 4 %X A unique data set was sampled by aircraft, ship, drift buoys and satellites in a strong storm event which occurred over the Norwegian Sea in March 2005 during the LOFZY field experiment. The atmospheric characteristics and the impact on the upper ocean are investigated. The storm field with winds up to 27 m s−1 was situated on the west-side of a low-pressure trough along the Norwegian coast and was marked by a sharp wind front. The entire system of trough, front and storm field was about 200 km wide, had a lifetime of 2 d in the area and advanced at 1–3 m s−1 SE-wards. Temperature contrast across the system was small, but wind contrast was remarkable and concentrated in a step-like front with 5–15 m s−1 difference over a distance of 3 km. The entire system was restricted to the lowest 2 km. It was accompanied by wide-spread rain and snow. Precipitation slightly surpassed evaporation (0.22 mm h−1). Surface heat fluxes amounted up to 400 W m−2. However, they cannot account for the observed sea surface temperature changes between −0.8 and +0.1 K within 6 h during the frontal passage. This is attributed to vertical mixing in the ocean caused by the frontal wind impact and superimposed to pre-existing mesoscale eddy circulations. The mixing acted on a temperature stratification in the uppermost 20–100 m which was opposite on both sides of the Norwegian Current. %0 journal article %@ 1386-2588 %A Schoo, K.L., Aberle, N., Malzahn, A.M., Boersma, M. %D 2010 %J Aquatic Ecology %P 233-242 %R doi:10.1007/s10452-009-9265-4 %T Does the nutrient stoichiometry of primary producers affect the secondary consumer Pleurobrachia pileus? %U https://doi.org/10.1007/s10452-009-9265-4 %X We investigated whether phosphorus limitations of primary producers propagate upwards through the food web, not only to the primary consumer level but also onto the secondary consumers’ level. A tri-trophic food chain was used to assess the effects of phosphorus-limited phytoplankton (the cryptophyte Rhodomonas salina) on herbivorous zooplankters (the copepod Acartia tonsa) and finally on zooplanktivores (the ctenophore Pleurobrachia pileus). The algae were cultured in phosphorus-replete and phosphorus-limited media before being fed to two groups of copepods. The copepods in turn were fed to the top predator, P. pileus, in a mixture resulting in a phosphorus-gradient, ranging from copepods having received only phosphorus-replete algae to copepods reared solely on phosphorus-limited algae. The C:P ratio of the algae varied significantly between the two treatments, resulting in higher C:P ratios for those copepods feeding on phosphorus-limited algae, albeit with a significance of 0.07. The differences in the feeding environment of the copepods could be followed to Pleurobrachia pileus. Contrary to our expectations, we found that phosphorus-limited copepods represented a higher quality food source for P. pileus, as shown by the better condition (expressed as nucleic acid content) of the ctenophore. This could possibly be explained by the rather high C:P ratios of ctenophores, their resulting low phosphorus demand and relative insensitivity to P deficiency. This might potentially be an additional explanation for the observed increasing abundances of gelatinous zooplankton in our increasingly phosphorus-limited coastal seas. %0 journal article %@ 0921-8971 %A Marxen, K., Vanselow, K.H., Hintze, R., Lippemeier, S., Ruser, A., Egge, B., Colijn, F., Hansen, U.-P. %D 2010 %J Journal of Applied Phycology %P 677-690 %R doi:10.1007/s10811-010-9507-9 %T Comparison of two different modes of UV-B irradiation on synthesis of some cellular substances in the cyanobacterium Synechocystis sp. PCC6803 %U https://doi.org/10.1007/s10811-010-9507-9 %X Two different modes of UV-B irradiation of the cyanobacterium Synechocystis sp. PCC 6803 are compared: turbidostatic control and additional physiostatic control. Under turbidostatic control, the cells were exposed to different constant UV-B irradiances, whereas under physiostatic control, an electronic control loop modulated UV-B irradiance in such a way that photosynthetic efficiency ϕ PSII was kept constant at a fixed set point. The UV-B-induced stimulation of the synthesis of pigments, α-tocopherol, and the antioxidative potential of methanolic soluble components of Synechocystis showed significant differences depending on the mode of irradiation, even though the overall doses were equal. For example, compared to the initial values, the concentrations of myxoxanthophyll and zeaxanthin increased to 226–244% and 453% upon constant UV-B irradiation in turbidostatic processes, whereas maxima of 600% and 740% were reached in turbidostatic process with additional physiostatic control. The α-tocopherol concentration increased under constant UV-B irradiances, up to a maximum of 150%. Under physiological control, however, maximum increases of 390% over the initial values were measured. Furthermore, a reaction scheme is given explaining the higher yield under physiostatic control. %0 journal article %@ 0029-8549 %A Malzahn, A.M., Hantzsche, F., Schoo, K.L., Boersma, M., Aberle, N. %D 2010 %J Oecologia %P 35-48 %R doi:10.1007/s00442-009-1458-y %T Differential effects of nutrient-limited primary production on primary, secondary or tertiary consumers %U https://doi.org/10.1007/s00442-009-1458-y %X Nutritional imbalances between predator and prey are the rule rather than the exception at the lower end of food webs. We investigated the role of different grazers in the propagation of nutritionally imbalanced primary production by using the same primary producers in a three-trophic-level food chain and a four-trophic-level food chain experimental setup. The three-trophic-level food chain consisted of a classic single-cell primary producer (Rhodomonas salina), a metazoan grazer (the copepod Acartia tonsa) and a top predator (the jellyfish Gonionemus vertens), while we added a protozoan grazer (Oxyrrhis marina) as primary consumer to the food chain to establish the four-trophic-level food chain. This setup allowed us to investigate how nutrient-limitation effects change from one trophic level to another, and to investigate the performance of two components of our experimental food chains in different trophic positions. Stoichiometry and fatty acid profiles of the algae showed significant differences between the nutrient-depleted [no N and no P addition (−P), respectively] and the nutrient-replete (f/2) treatments. The differences in stoichiometry could be traced when O. marina was the first consumer. Copepods feeding on these flagellates were not affected by the nutritional imbalance of their prey in their stoichiometry, their respiration rates nor in their developmental rates. In contrast, when copepods were the primary consumer, those reared on the −P algae showed significantly higher respiration rates along with significantly lower developmental rates. In neither of our two experimental food chains did the signals from the base of the food chains travel up to jelly fish, our top predator. %0 conference paper %@ %A Hydes, D., Kelly-Gerreyn, B., Colijn, F., Petersen, W., Schroeder, F., Mills, D., Durand, D., Wehde, H., Sørensen, K., Morrison, G. %D 2010 %J Proceedings of OceanObs’09: Sustained Ocean Observations and Information for Society %R doi:10.5270/OceanObs09.cwp.46 %T The Way Forward in Developing and Integrating Ferrybox Technologies %U https://doi.org/10.5270/OceanObs09.cwp.46 %X Co-operation between scientists and the shipping industry offers great potential over the next decade for the expansion of marine observations. Work with so called "Ferry-boxes" has made large advances in the last ten years focusing on shelf seas. We expect this work to expand globally and link into other operations more focused on the open sea and sub surface measurements. This may be through the more organised alliances currently being considered by SCOR-OceanScope (Scientific Committee on Oceanic Research-Working Group) (www.scor-int.org/Working_Groups/wg133.htm). It would be timely to consider bringing a global pilot project into being as part of Coastal GOOS (Global Ocean Observing System). The term "Ferry-box" signifies (1) the use of a ferry (or other commercial ships) for data collection, (2) boxes of autonomous sensing equipment installed on the ship, and (3) the ability of the data to provide boundary conditions for numerical models in a delimited or boxed region. The EU (European) project FerryBox (2002-2005) demonstrated that it is possible to provide surface ocean data from commercial ships in a highly cost effective manner over a wide range of temporal and spatial scales. The concept is now in use globally, particularly in Europe, Australia, Japan, Korea and the USA. The focus of Ferry-box activity has been on improving the understanding of biogeochemical and biological processes in shelf seas. The Ferry-box concept has considerable potential for expansion to include the study of inputs from the world's major riverine discharges and more generally to provide operational observations over coastal zones, shelf seas and the open ocean. This potential for expansion should be strongly encouraged. Immediate requirements are for improvements in the reliability and robustness of existing systems, particularly for measuring nutrients, pCO2 and pH as well as extension to already trialled equipment such as Acoustic Doppler Current Profilers (ADCP) and flow cytometers. In Europe, the output from Ferry-box systems is now seen as an important part of a pan European observational system for integration into data networks (e.g. EMODNET - European Marine Observation and Data Network) for use in marine management. Practically, this integration is beginning to evolve through initiatives such as the EU Framework 7 projects MyOcean (2009-2012) and EMECO (European Marine Ecosystem Observatory), which will link to national systems such as COSYNA (Coastal Observation System for Northern and Arctic Seas). The use of Ferry-boxes within these observational systems and networks will enhance the provision of much needed data to enable for example more reliable assessments of the ocean's ability to sequester CO2, and the OSPAR (Oslo/Paris convention (for the Protection of the Marine Environment of the North-East Atlantic) Common Procedure looking at eutrophication. %0 journal article %@ 0025-3162 %A Hantzsche, F., Boersma, M. %D 2010 %J Marine Biology %P 1641-1651 %R doi:10.1007/s00227-010-1437-1 %T Dietary-induced responses in the phagotrophic flagellate Oxyrrhis marina %U https://doi.org/10.1007/s00227-010-1437-1 %X Primary producers may be limited by different nutrients as well as by light availability, which in turn affects their quality as food for higher trophic levels. Typically, algae with high C:N and/or C:P ratios are low-quality food for consumers. Heterotrophic protists are important grazers on these autotrophes, but despite their importance as grazers, knowledge of food quality effects on heterotrophic protists is sparse. In the present study, we examined how differently grown Rhodomonas salina (nutrient replete, N-limited and P-limited) affected the phagotrophic flagellate Oxyrrhis marina. The functional response of O. marina (based on ingested biovolume) did not show significant differences between food sources, thus food uptake was independent of food quality. O. marina was weakly homoeostatic which means that its C:N:P ratio still reflected the elemental composition of its food to some extent. Food quality had a significantly negative effect on the numerical response of O. marina. Whereas N-limited R. salina and nutrient replete R. salina resulted in similar growth rates, P-limited algae had a significantly negative effect on the specific growth rate of O. marina. Hence, the lack of elemental phosphorus of O. marina feeding on P-limited algae caused a reduction in growth. Thus, despite their weaker homoeostasis, heterotrophic protists are also affected by high C:P food in a similar way to crustacean zooplankton. %0 journal article %@ 1385-1101 %A Loebl, M., Colijn, F., van Beusekom, J.E.E., Baretta-Bekker, J.G., Lancelot, C., Philippart, C.J.M., Rousseau, V., Wiltshire, K.H. %D 2009 %J Journal of Sea Research %N 1-2 %P 34-43 %R doi:10.1016/j.seares.2008.10.002 %T Recent patterns in potential phytoplankton limitation along the Northwest European continental coast %U https://doi.org/10.1016/j.seares.2008.10.002 1-2 %X The European coastal zone is characterized by high anthropogenic riverine nutrient loads, and turbid waters along the continental North Sea coastal stretch. Riverine nutrient inputs (N and P) have increased since the 1950's and have decreased again since the mid 1980's. Using the approach of Cloern (Cloern, J.E., 1999. Aquatic Ecology 33, 3–16), we analyzed potential limitation patterns of light and nutrients (DIN, PO4, Si) for seven long-term monitoring stations along the North Sea coast. As available, data from 1990 until 2005 were analyzed. Underwater irradiance was the dominant factor potentially limiting phytoplankton growth. Seasonal limitation patterns strongly differed between the investigated sites. Si limitation was the most common among the stations followed by PO4 limitation. Only one station with optimum light conditions (northern Wadden Sea) resulted a potential DIN limitation. An increase in nutrient limitation, or co-limitation of light and nutrients, was observed off the Dutch coast (DIN and PO4), and in the German Bight near Helgoland (DIN, PO4, Si) within the period from 1990 until 2005. However, we observed no clear effects of nutrient reduction measures in shallow areas of the Wadden Sea during the period studied. We conclude that long-term nutrient limitation patterns are consistent and site dependent, and strongly linked to the local hydrography and light conditions of the water column. %0 journal article %@ 0921-8971 %A Diercks, S., Gescher, C., Metfies, K., Medlin, L. %D 2009 %J Journal of Applied Phycology %N 6 %P 657-668 %R doi:10.1007/s10811-008-9399-0 %T Evaluation of locked nucleic acids for signal enhancement of oligonucleotide probes for microalgae immobilised on solid surfaces %U https://doi.org/10.1007/s10811-008-9399-0 6 %X Biosensors and microarrays are powerful tools for species detection and monitoring of microorganisms. A reliable identification of microorganisms with probe-based methods requires highly specific and sensitive probes. The introduction of locked nucleic acid (LNA) promises an enhancement of specificity and sensitivity of molecular probes. In this study, we compared specificity and sensitivity of conventional probes and LNA modified probes in two different solid phase hybridisation methods: sandwich hybridisation on biosensors and on DNA microarrays. In combination with DNA-microarrays, the LNA probes displayed an enhancement of sensitivity, but also gave more false-positive signals. With the biosensor, the LNA probes showed neither signal enhancement nor discrimination of a single mismatch. In all cases, conventional DNA probes showed equal or better results than LNA probes. In conclusion, LNA technology may have great potential in methods that use probes in suspension and in gene expressions studies, but under certain solid surface-hybridisation applications, they do not improve signal intensity. %0 conference paper %@ %A Flampouris, S., Seemann, J., Ziemer, F. %D 2009 %J Proceedings, 2009 IEEE International Geoscience and Remote Sensing Symposium %P III-760 %R doi:10.1109/IGARSS.2009.5417875 %T Observing litteral waves by doppler waves %U https://doi.org/10.1109/IGARSS.2009.5417875 %X The offshore observation of the wavefield with coherent radar systems consist a common practice for the study of the electromagnetic waves probing the sea surface waves and for the extraction of information of the sea waves. In this investigation, a Dopplerized, horizontally polarized, nautical radar is utilized for the monitoring of the wavefield evolution in the littoral zone. The radar datasets are globally unique and cover different geophysical conditions; therefore the impact of the bathymetry on the Doppler spectra is discussed, the horizontal velocity towards the shore is calculated and the properties of the radar deduced quantities are compared with in situ measurements. %0 conference poster %@ %A Breitbach, G., Krasemann, H., Onken, R. %D 2009 %J Data Management Workshop %T Datamanagement in COSYNA %U %X %0 conference lecture %@ %A Riethmueller, R., Colijn, F., Breitbach, G., Krasemann, H., Petersen, W., Schroeder, F., Ziemer, F. %D 2009 %J OceanObs 2009 %T COSYNA, a German Initiative for an Integrated Coastal Observation System %U %X %0 conference paper %@ %A Mueller, J.-M., Riethmueller, R., Onken, R. %D 2009 %J COASTAL ENGINEERING 2008, Proceedings of the 31st International Conference on Coastal Engineering %P 1664-1670 %R doi:10.1142/9789814277426_0138 %T Multiple Time Scale Analysis of Suspended Sediment Concentration in the Wadden Sea %U https://doi.org/10.1142/9789814277426_0138 %X A frequency analysis was carried out on an 8-month high frequency data set of suspended particulate matter concentration (SPMC) measurements taken in a tidal inlet of the German Wadden Sea. It was found that about 50% of the variability in SPMC from March 2006 to October 2006 is due to tidal forcing. The non-tidally influenced dynamics in SPMC are well correlated but slightly delayed to wind speed time-series. %0 conference paper %@ %A Breitbach, G., Krasemann, H. %D 2009 %J Geoinformationen fuer die Kuestenzone, Beitraege des 2. Hamburger Symposiums %P 105-114 %T Neue Geodateninfrastruktur beim GKSS Institut fuer Kuestenforschung (CODM) %U %X %0 conference poster %@ %A Riethmueller, R., Colijn, F., Stanev, E., Schroeder, F., Wirtz, K. %D 2009 %J OceanObs 2009 %T COSYNA, a German Initiative of an Integrated Coastal Observating System %U %X %0 journal article %@ 0304-3800 %A Scharfe, M., Callies, U., Bloecker, G., Petersen, W., Schroeder, F. %D 2009 %J Ecological Modelling %N 18 %P 2173-2186 %R doi:10.1016/j.ecolmodel.2009.04.048 %T A simple Lagrangian model to simulate temporal variability of algae in the Elbe River %U https://doi.org/10.1016/j.ecolmodel.2009.04.048 18 %X We present a five-year (1997–2001) numerical simulation of daily mean chlorophyll a concentrations at station Geesthacht Weir on the lower Elbe River (Germany) using an extremely simple Lagrangian model driven by (a) water discharge, global radiation, water temperature, and (b) silica observations at station Schmilka in the upper reach of the Elbe River. Notwithstanding the lack of many mechanistic details, the model is able to reproduce observed chlorophyll a variability surprisingly well, including a number of sharp valleys and ascents/descents in the observed time series. The model's success is based on the assumption of three key effects: prevailing light conditions, sporadic limitation of algal growth due to lack of silica and algae loss rates that increase above an empirically specified temperature threshold of 20 °C. Trimmed-down model versions are studied to analyse the model's success in terms of these mechanisms.In each of the five years the model consistently fails, however, to properly simulate characteristic steep increases of chlorophyll a concentrations after pronounced spring minima. Curing this model deficiency by global model re-calibration was found to be impossible. However, suspension of silica consumption by algae for up to 10 days in spring is shown to serve as a successful placeholder for processes that are disregarded in the model but apparently play an important role in the distinctly marked period of model failure. For the remainder of the year the very simple model was found to be adequate. %0 conference lecture %@ %A Onken, R., Riethmueller, R. %D 2009 %J 41st International Liege Colloquium on Ocean Dynamics %T An integrated observation system for tidal flat areas %U %X %0 conference lecture %@ %A Riethmueller, R., Colijn, F., Krasemann, H., Schroeder, F., Ziemer, F. %D 2009 %J OCEANS 09 IEEE Bremen %T COSYNA, an Integrated Coastal Observation System for Northern and Arctic Seas %U %X %0 conference lecture %@ %A Riethmueller, R., Colijn, F., Stanev, E., Wirtz, K. %D 2009 %J 41st International Liege Colloquium on Ocean Dynamics: Science based management of the coastal waters %T COSYNA, an Integrated Coastal Observation System for Northern and Arctic Seas %U %X %0 journal article %@ 1323-1650 %A Boersma, M., Becker, C., Malzahn, A.M., Vernooij, S. %D 2009 %J Marine and Freshwater Research %N 10 %P 983-989 %R doi:10.1071/MF08240 %T Food chain effects of nutrient limitation in primary producers %U https://doi.org/10.1071/MF08240 10 %X The propagation of mineral limitation in primary producers to the second consumer level has rarely been investigated. Recently, it has been shown that limitation effects do travel up the food chain, not only quantitatively, but also qualitatively, and also that these quality effects affect the nutritional condition and growth of secondary consumers. The present study experimentally investigated the effect of phosphorus limitation in combination with fatty acid addition in primary producers (Scenedesmus obliquus) channelled through a primary consumer (Daphnia magna) on the condition of larval rainbow trout (Oncorhynchus mykiss). The C : P ratio and the fatty acid concentrations of the primary producers varied significantly with the phosphorus concentration of the culture media. These differences were also visible in the primary consumers (D. magna) feeding on the algae. The significantly different stoichiometry and fatty acid concentrations of the daphnids fed to larval trout did not lead to significant differences in growth, but the additional supplementation of fatty acid emulsions caused a significant increase in the condition of the fish. It was found that in the case of Daphnia as the primary prey for fish, with its relatively high phosphorus content even under phosphorus limitation, it is unlikely that phosphorus limitation affects fish condition and growth. %0 conference lecture (invited) %@ %A Colijn, F. %D 2009 %J 4th Meeting of the Marine Observation and Data Expert Group %T FerryBox System Presentation %U %X %0 journal article %@ 1400-0350 %A Hamre, T., Krasemann, H., Groom, S., Dunne, D., Breitbach, G., Hackett, B., Soerensen, K., Sandven, S. %D 2009 %J Journal of Coastal Conservation %N 1 %P 1-13 %R doi:10.1007/s11852-009-0046-y %T Interoperable web GIS services for marine pollution monitoring and forecasting %U https://doi.org/10.1007/s11852-009-0046-y 1 %X This paper presents services and systems developed in the FP6 InterRisk (Interoperable GMES Services for Environmental Risk Management in Marine and Coastal Areas of Europe) project, which addresses the need for better access to information for risk management in Europe, both in cases of natural hazards and industrial accidents. The overall objective of the project is to develop a pilot system for interoperable GMES monitoring and forecasting services for environmental management in marine and coastal areas. This pilot system is based on established and widely adopted web-GIS standards, in line with INSPIRE recommendations. The pilot is comprised of, among other things, a portal and a web-GIS map viewer, both developed using open source tools. Providers using commercial tools adhering to the adopted standards, however, can also deliver products to the InterRisk pilot. The InterRisk services and system are based on a combination of free and commercial software, and have been demonstrated to end-users in three European areas: Norwegian, UK and Irish waters, and German and Polish waters. Products and services offered in these areas are presented, along with an outline of the technical development of web-GIS clients and portals. %0 conference lecture %@ %A Floeser, G., Onken, R., Riethmueller, R. %D 2009 %J OCEANS 2009 EUROPE, OCEANS 09 %T Automated measuring stations in the German Wadden Sea %U %X %0 conference lecture (invited) %@ %A Colijn, F., Riethmueller, R., Schroeder, F., Stanev, E., Wirtz, K. %D 2009 %J 3rd MarinEra Infrastructure Workshop %T COSYNA - Coastal Observing System of Northern and Arctic Seas %U %X %0 conference lecture %@ %A Flampouris, S., Seemann, J., Ziemer, F. %D 2009 %J OCEANS 2009 %T Sharing our experience using wave theories inversion for the determination of the local depth %U %X %0 conference lecture %@ %A Flampouris, S., Ziemer, F., Seemann, J. %D 2009 %J International Geoscience and Remote Sensing Symposium %T Observing litteral waves by doppler waves %U %X %0 journal article %@ 0272-7714 %A Grunwald, M., Dellwig, O., Beck, M., Dippner, J.W., Freund, J.A., Kohlmeier, C., Schnetger, B., Brumsack, H.-J. %D 2009 %J Estuarine, Coastal and Shelf Science %N 4 %P 445-456 %R doi:10.1016/j.ecss.2008.11.021 %T Methane in the southern North Sea: Sources, spatial distribution and budgets %U https://doi.org/10.1016/j.ecss.2008.11.021 4 %X Based on our data, two model calculations were used to estimate the impact of tidal flats on the CH4 budget in the German Bight. Our results demonstrate that the back barrier tidal flats of the east Frisian Wadden Sea contribute CH4 in an order of magnitude between the Wash estuary and River Elbe and thus have to be considered in budget calculations. %0 journal article %@ 1434-2944 %A Boersma, M., Aberle, N., Hantzsche, F.M., Schoo, K., Wiltshire, K.H., Malzahn, A.M. %D 2009 %J International Review of Hydrobiology %N 4-5 %P 479-488 %R doi:10.1002/iroh.200811066 %T Nutritional Limitation Travels up the Food Chain %U https://doi.org/10.1002/iroh.200811066 4-5 %X It is a well accepted fact that nutrient limitation of plants affects the growth and survival of herbivores, generally leading to lower performance of herbivores feeding on nutrient stressed plants. The effect of plants' growing conditions on predatory organisms, feeding one trophic level up, has been much less studied, and there is a general consensus that such effects would be small as herbivores often show relatively strong homeostasis with respect to their nutrient content. Here, we challenge this view, and show from several examples that despite the fact that herbivores buffer much of the variance in nutrient stoichiometry of their food, effects of growing conditions of the primary producers can travel up the food chain. We discuss the implications of these findings, and argue that phosphorus limitation of secondary consumers might be more common in marine than in freshwater systems. %0 journal article %@ 0924-7963 %A Stockmann, K., Riethmueller, R., Heineke, M., Gayer, G. %D 2009 %J Journal of Marine Systems %N 3-4 %P 409-420 %R doi:10.1016/j.jmarsys.2007.04.010 %T On the morphological long-term development of dumped material in a low-energetic environment close to the German Baltic coast %U https://doi.org/10.1016/j.jmarsys.2007.04.010 3-4 %X The morphological changes were small and their quantification required a high measuring precision in the order of few cm in the vertical. The dominant processes of surface deformation was flattening of peaks and filling of troughs. The speed of this process decreased with horizontal scale: structures of less than 4 m horizontal extension had a trend to disappear within less than five years, whereas structures of larger than 8 m extension showed little change and are estimated to remain detectable for many decades. In contrast to the reworking of the matter inside the dumping structures, no net transport of material out of the dumping area could be detected. Extrapolating the observed morphological changes into the future it is estimated that without significant decrease in internal shear strength of the disposed till the structures will persist for at least 70 years. This can be attributed to the high internal stability of the dumped glacial till and the low hydrodynamic forces present at the seabed in this region. %0 journal article %@ 0025-3227 %A Boening, P., Brumsack, H.-J., Schnetger, B., Grunwald, M. %D 2009 %J Marine Geology %N 1-4 %P 112-121 %R doi:10.1016/j.margeo.2009.01.004 %T Trace element signatures of Chilean upwelling sediments at ~ 36°S %U https://doi.org/10.1016/j.margeo.2009.01.004 1-4 %X Here, for a meaningful discussion, total contents of As, Bi, Co, Cr, Cu, Ni, Pb, Sb, Tl, V, U and Zn were corrected for the lithogenic background by determining TE/Al ratios from local river samples. The latter showed significantly lower TE/Al ratios than average shale, crust or andesite which are classically used for background correction. Hence, the precise assessment of the lithogenic TE contribution for the calculation of authigenic TE contents allows to examine the source–sink relationship of individual authigenic TE. For Chilean sediments four TE groups may be distinguished: (i) Mo, Re, U and Sb likely originate from sea water and accumulate via diffusive supply across the SWI, (ii) Cd, Cr, Cu, Ni and Zn require biologically-induced pre-concentration within biogenic material, (iii) Ag, As, Se, Tl and V show an intermediate behaviour and (iv) Bi and Pb are contributed by anthropogenic activity. Highest enrichments in Ni, Cu, U, As and V occur in sediments in contact with the OMZ. The distinct depletion in Co (along with Mn) indicates the overall reducing, but non-sulfidic character of the Chilean OMZ. The degree of sedimentary sulfate reduction seems to be the most important control on Chilean and Peruvian near-coastal enrichment of Cd, Mo and U. %0 conference paper %@ %A Riethmueller, R., Colijn, F., Krasemann, H., Schroeder, F., Ziemer, F. %D 2009 %J Proceedings of Oceans 09 IEEE Bremen, Balancing technology with future needs %P CD %T COSYNA, an Integrated Coastal Observation System for Northern and Arctic Seas %U %X %0 journal article %@ 1616-7341 %A Kowalski, N., Dellwig, O., Beck, M., Grunwald, M., Ficher, S., Piepho, M., Riedel, T., Freund, H., Brumsack, H.-J., Boettcher, M.E. %D 2009 %J Ocean Dynamics %N 2 %P 333-350 %R doi:10.1007/s10236-009-0192-7 %T Trace metal dynamics in the water column and pore waters in a temperate tidal system: Response to the fate of algae derived organic matter %U https://doi.org/10.1007/s10236-009-0192-7 2 %X Tidal and seasonal behaviour of the redox-sensitive trace metals Mn, Fe, Mo, U, and V have been investigated in the open-water column and shallow pore waters of the backbarrier tidal flats of the island of Spiekeroog (Southern North Sea) in 2002 and 2007. The purpose was to study the response of trace metal cycles on algae blooms, which are assumed to cause significant changes in the redox state of the entire ecosystem. Trace metal data were complemented by measurements of nutrients and enumeration of algae cells in 2007. Generally, Mn and V show a tidal cyclicity in the water column with maximum values during low tide which is most pronounced in summer due to elevated microbial activity in the sediments. Mo and U behave almost conservatively throughout the year with slightly increasing levels towards high tide. Exceptions are observed for both metals after summer algae blooms. Thus, the seasonal behaviour of the trace metals appear to be significantly influenced by productivity in the water column as the occurrence of algae blooms is associated with an intense release of organic matter (e.g. transparent exopolymer particles, TEP) thereby forming larger organic-rich aggregates. Along with elevated temperatures in summer, the deposition of such aggregates favours microbial activity within the surface sediments and release of DOC, nutrients and trace metals (Mn, Mo and V) during the degradation of the aggregates. Additionally, pronounced reducing conditions lead to the reduction of Mn(IV)-oxides and Fe(III)-(oxihydr)oxides, thereby releasing formerly scavenged compounds as V and phosphate. Therefore, pore-water profiles show significant enrichments in trace metals especially from July to September. Finally, the trace metals are released to the open water column via draining pore waters (esp. Mo, Mn, and V) and/or fixed in the sediment as sulphides (Fe, Mo) and bound to organic matter (U). Non-conservative behaviour of Mo in oxygenated seawater, first observed in the investigation area by Dellwig et al. (Geochim Cosmochim Acta 71:2745–2761, 2007a), was shown to be a recurrent phenomenon which is closely coupled to bacterial activity after the breakdown of algae blooms. In addition to the postulated fixation of Mo in oxygen-depleted micro-zones of the aggregates or by freshly formed organic matter, a direct removal of Mo from the water column by reduced sediment surfaces may also play an important role. %0 conference paper %@ %A Floeser, G., Onken, R., Riethmueller, R. %D 2009 %J OCEANS 2009 EUROPE, OCEANS 09 %P 1-4 %R doi:10.1109/OCEANSE.2009.5278205 %T Automated measuring stations in the German Wadden Sea %U https://doi.org/10.1109/OCEANSE.2009.5278205 %X Since 1996, GKSS Research Centre operates automated measuring stations in German coastal areas. These stations are equipped with meteorological (wind speed and direction, relative humidity, air temperature and pressure, solar radiation, precipitation) and hydrographical sensors (water velocity, pressure and temperature, turbidity, conductivity, pH, O2 saturation, fluorescence). From the data, information can be extracted as to water and salt exchange between the German Wadden Sea and the North Sea. Turbidity measurements allow drawing conclusions as to the suspended matter dynamics, and the recently installed oxygen and fluorescence sensors yield information concerning primary production. %0 journal article %@ 1437-3254 %A Beusekom, J.E.E.van, Mengedoht, D., Augustin, C.B., Schilling, M., Boersma, M. %D 2009 %J International Journal of Earth Sciences %N 2 %P 251-260 %R doi:10.1007/s00531-007-0231-x %T Phytoplankton, protozooplankton and nutrient dynamics in the Bornholm Basin (Baltic Sea) in 2002–2003 during the German GLOBEC Project %U https://doi.org/10.1007/s00531-007-0231-x 2 %X From March 2002 to until April 2003 we investigated the seasonal nutrient and phytoplankton dynamics in the central Bornholm Basin (Baltic Sea) within the framework of the German GLOBEC Project. We choose a nested approach consisting of vertical fluorescence profiles, phytoplankton counts and nutrient analyses. The Fluoroprobe (MultiProbe, BBE Moldaenke) is capable of distinguishing four algal groups (Cryptophyceae, Cyanophyceae, Chlorophyceae, Bacillariophyceae + Dinophyceae). Winter nutrient concentrations were about 5 μM NO3 and 0.5 μM PO4 in the central Basin. The spring phytoplankton bloom was dominated by the diatom Skeletonema sp. and reached a maximum of about 270 μg C/l before the onset of the seasonal stratification. Protozooplankton was dominated by the Mesodinium rubrum (a phototrophic ciliate = Myrionecta rubra) and reached a maximum biomass of about 200–300 μg C/l about 2 weeks after the demise of the diatom spring bloom. During summer, the water column was stratified and a subsurface maximum developed near the thermocline consisting of Bacillariophyceae, Cryptophycea and other phototrophic flagellates. Phytoplankton and protozooplankton biomass was generally low. Nutrient concentrations point towards a nitrogen limitation during this period. The stratification period ended during September and surface nutrient concentrations increased again. Protozooplankton reached a second maximum during September. With the Fluoroprobe small scale structures in the plankton community could be detected like a subsurface Cryptophyceae maximum near the thermocline that however, could not be confirmed by cell counts. The chlorophyll a estimate of the Fluoroprobe was in good agreement with the phytoplankton biomass estimated from counts. We conclude that only by combining modern sensing technology with microscopy, the small-scale dynamics and taxonomic spectrum of the plankton can be fully captured. %0 conference paper %@ %A Flampouris, S., Seemann, J., Ziemer, F. %D 2009 %J OCEANS 2009 - Europe %P 1-7 %R doi:10.1109/OCEANSE.2009.5278331 %T Sharing our experience using wave theories inversion for the determination of the local depth %U https://doi.org/10.1109/OCEANSE.2009.5278331 %X The determination of the nearshore bathymetry by inverting the propagation of the wave field over shallow waters as observed by ground based X-band radar has became recently part of the coastal monitoring routing. In this investigation, four different wave theories, linear, solitary, modified cnoidal and Stokes extended to shallow waters, are inverted by using the Dispersive Surface Classificator, DiSC, methodology. This is the first time that the efficiency of the previously mentioned theories for the determination of the depth is validated with multibeam echosounder data acquired two days before the radar data acquisition. The performance of the four wave models for the extraction of the local depth is discussed. The resulted bathymetries in all cases are significant, but the sources of the error are different. %0 conference object %@ %A Flampouris, S., Ziemer, F., Schymura, G. %D 2008 %J From the Watershed to the Global Ocean , Meeting Abstracts, 2008 Ocean Sciences Meeting %P 128-129 %T High temporal and spatial resolution monitoring of the bathymetry and current field in coastal areas by using ground based X-Band radar %U %X %0 journal article %@ 0924-7963 %A Onken, R., Alvarez, A., Fernandez, V., Vizoso, G., Basterretxea, G., Tintore, J., Haley, P., Nacini, E. %D 2008 %J Journal of Marine Systems %N 1-2 %P 79-98 %R doi:10.1016/j.jmarsys.2007.05.008 %T A forecast experiment in the Balearic Sea %U https://doi.org/10.1016/j.jmarsys.2007.05.008 1-2 %X Taking into account further available options of HOPS (implementation of additional tracers, tracking of Lagrangian particles, biological modules, two-way nesting), the system is operational for a wide field of possible applications. %0 conference lecture %@ %A Flampouris, S., Ziemer, F., Schymura, G. %D 2008 %J From the Watershed to the Global Ocean , 2008 Ocean Sciences Meeting %T High temporal and spatial resolution monitoring of the bathymetry and current field in coastal areas by using ground based X-Band radar %U %X %0 conference lecture %@ %A Onken, R., Petersen, W. %D 2008 %J EGU General Assembly 2008 %T Assimilation of FerryBox data in a circulation model of the North Sea %U %X %0 conference lecture %@ %A Onken, R., Tintore, J., Vizoso, G., Alvarez, A. %D 2008 %J EGU General Assembly 2008 %T Presence and future of a coastal forecasting system in the Balearic Sea %U %X %0 conference lecture %@ %A Schartau, M., Engel, A., Colijn, F. %D 2008 %J ICES 2008 Annual Science Conference %T Transformation of dissolved organic matter and its diverse effect on higher trophic level %U %X %0 report part %@ %A Onken, R., Ruiz, S., Vizoso, G., Garau, B., Basterretxea, G., Casas, B., Alvarez, A., Tintore, J., Testor, P., Send, U., Lherminier, P., Terre, T. %D 2008 %J MERSEA-Abschlussreport %P 1-9 %T Impact of biogeochemical glider data on modelling %U %X %0 journal article %@ 0272-7714 %A Petersen, W., Wehde, H., Krasemann, H., Colijn, F., Schroeder, F. %D 2008 %J Estuarine, Coastal and Shelf Science %N 2 %P 296-307 %R doi:10.1016/j.ecss.2007.09.023 %T FerryBox and MERIS – Assessment of coastal and shelf sea ecosystems by combining in situ and remotely sensed data %U https://doi.org/10.1016/j.ecss.2007.09.023 2 %X strategies are shown, both for large scale algal blooms in the North Sea as well as for local intense but short term blooms in the German Bight. Coherence of the data sets can be gained and improved by using water transport models in order to obtain synoptic overviews of the remote sensed and FerryBox related parameters. Limitations of the currently used algorithms for deriving chlorophyll-a from remote sensing images for coastal and shelf seas (Case-2 water) are discussed, as well as depth related processes which can not be properly resolved on the basis of water intake at a fixed point. However, in mixed coastal waters under normal conditions FerryBox data represent average conditions. The importance of future applications of these combination of methods for monitoring of coastal waters is emphasized. %0 journal article %@ 0196-2892 %A Braun, N., Ziemer, F., Bezuglov, A., Cysewski, M., Schymura, G. %D 2008 %J IEEE Transactions on Geoscience and Remote Sensing %N 4-2 %P 1125-1133 %R doi:10.1109/TGRS.2007.910221 %T Sea-Surface Current Features Observed by Doppler-Radar %U https://doi.org/10.1109/TGRS.2007.910221 4-2 %X A coherent X-band radar was operated from the shore to measure velocities at the sea surface. The test site at a tidal inlet (Lister Tief) in the German Bight lay protected from swell and long wind waves. A vertical–vertical antenna was used to obtain the backscattered radar signal caused by Bragg scattering. To cover a sector of the circle, the antenna was rotated in 1$^{circ}$ steps. At each step, the data acquisition was performed to obtain a time series of the backscattered radar signal. The maximum range is 1905 m with a range resolution of 7.5 m and an azimuthal resolution of 3.5 $^{circ}$. Maps of the averaged backscattered radar power and radial Doppler velocities are obtained. The radar backscatter maps show the modulation of the radar cross section due to changes in the surface roughness. The radar Doppler velocity maps show the modulations of the surface scatterer speed. The maps show many features, for example, the impact of subsurface sand waves, eddies, current shears, slicks, ship wakes, atmospheric effects, and small-scale current changes behind sheet pile walls. As the radar backscatter is caused by short wind waves, the wind influence on the Doppler signal was calculated for a first attempt to obtain true current motions. The results were compared with in situ current measurements. By subsequently measuring the surfaces current from two radar positions and performing the wind correction, the current vector fields are assessed. %0 conference poster %@ %A Buerk, D., Klaucke, I. %D 2008 %J Acoustics 2008 %T The influence of topography on sidescan sonar images %U %X %0 conference lecture %@ %A Krasemann, H., Breitbach, G., Schoenfeld, W. %D 2008 %J International Conference On Marine Data and Information Systems, IMDIS 2008 %T Integrating Real Time Data on North Sea and Baltic Waters as Web-Services for Monitoring and Risk Assessment %U %X %0 conference poster %@ %A Schiller, H., Krasemann, H. %D 2008 %J MERIS/(A)ATSR User Workshop 2008 %T A Precise "Smile-Correction" for MERIS Oxygen Band %U %X %0 conference lecture %@ %A Breitbach, G., Krasemann, H. %D 2008 %J Geoinformationen fuer die Kuestenzone, 2. Hamburger Symposium %T Neue Geodateninfrastruktur beim GKSS Institut fuer Kuestenforschung (CODM) %U %X %0 journal article %@ 1438-387X %A Loebl, M., Colijn, F., Beusekom, J.E.E.van %D 2008 %J Helgoland Marine Research %N 1 %P 59-65 %R doi:10.1007/s10152-007-0089-0 %T Increasing nitrogen limitation during summer in the List Tidal Basin (Northern Wadden Sea) %U https://doi.org/10.1007/s10152-007-0089-0 1 %X The European Wadden Sea is characterized by high nutrient loads and turbid waters. Riverine nutrient input showed a gradual decrease since the mid 1980s. In the List Tidal Basin (Northern Wadden Sea) the frequency of low NO3 values in summer has increased and decreasing mean annual suspended matter concentrations indicate an increasing underwater irradiance. We used an approach developed by Cloern (Aquat Ecol 33:3–16, 1999) to analyze resource limitation of nitrogen (DIN) and underwater irradiance for phytoplankton growth in the List Tidal Basin between 1985 and 2005. Comparing our results to other studies suggests that the List Tidal Basin is one of the most nitrogen sensitive areas of the European Wadden Sea. In 2005, phytoplankton growth was light limited from January to May and in November and December, co-limited by both resources in June, July and October, and nitrogen limited in August and September. Comparing phytoplankton growth limitation in the periods 1985–1991 and 1999–2005, the duration of nitrogen limitation during summer is significantly longer in the second period (2.1 ± 0.9 months) than in the first (0.7 ± 0.5). Moreover, light limitation in September and October has decreased in the second period. A decreasing phytoplankton growth during summer is in line with former studies from the List Tidal Basin, which showed that summer chlorophyll concentrations have decreased since the mid 1980s. We suggest that nowadays less food is available for higher pelagic and benthic trophic levels due an increased nitrogen limitation during summer. %0 conference paper %@ %A Flampouris, S., Ziemer, F., Seemann, J. %D 2008 %J International Geoscience and Remote Sensing Symposium, IGARSS 2007 %P 3579-3582 %R doi:10.1109/IGARSS.2007.4423619 %T Survey of bathymetry and current fields by radar image series acquired by shore based x-band radar %U https://doi.org/10.1109/IGARSS.2007.4423619 %X %0 conference lecture %@ %A Riethmueller, R., Colijn, F., Schroeder, F. %D 2008 %J Operational Coastal Oceanography Conference 2008 %T ICON, an Integrated Coastal Observation Network in the German North Sea %U %X %0 conference lecture %@ %A Schiller, H., Brockmann, C., Krasemann, H., Schoenfeld, W. %D 2008 %J MERIS/(A)ATSR User Workshop 2008 %T A Method for Detection and Transparency Classification of Clouds over Water %U %X %0 conference lecture %@ %A Onken, R., Riethmueller, R. %D 2008 %J 9th International Conference, LITTORAL 2008 %T The freshwater budget of mid-latitude tidelands %U %X %0 journal article %@ 0196-2892 %A Flampouris, S., Ziemer, F., Seemann, J. %D 2008 %J IEEE Transactions on Geoscience and Remote Sensing %N 10-1 %P 2906-2913 %R doi:10.1109/TGRS.2008.919687 %T Accuracy of Bathymetric Assessment by Locally Analyzing Radar Ocean Wave Imagery (February 2008) %U https://doi.org/10.1109/TGRS.2008.919687 10-1 %X In this paper, the error source in assessing the bathymetry by a recently presented method, the dispersive surface classificator, is discussed. This method is based on the analysis of X-band radar image sequences of sea-surface waves to determine spatial maps of hydrographic parameters. To implement this objective, the radar-deduced bathymetry is validating by multibeam echosounder data. The accuracy of the method is high in homogeneous areas and reduced at the areas of bathymetric gradient and lower but comparable with multibeam echosounder data, under the assumption of the spatial resolution. The identification of systematic correlation of the absolute value of the error with the slope is significant and insignificant with the actual depth itself. The spatial correlation of the error illustrates that the direction of the wave field influences the neighboring grid cell in the same direction. The application of the method during crucial weather conditions is the main advantage and permits the accurate operational nearshore monitoring for several applications. %0 journal article %@ 1863-9135 %A Roenicke, H., Doerffer, R., Siewers, H., Buettner, O., Lindenschmidt, K.E., Herzsprung, P., Beyer, M., Rupp, H. %D 2008 %J Fundamental and Applied Limnology : Archiv fuer Hydrobiologie %N 2 %P 111-119 %R doi:10.1127/1863-9135/2008/0172-0111 %T Phosphorus input by nordic geese to the eutrophic Lake Arendsee, Germany %U https://doi.org/10.1127/1863-9135/2008/0172-0111 2 %X Phosphorus import by nordic geese (Anser fabalis and Anser albifrons) was investigated in Lake Arendsee, located in the Saxony-Anhalt region, Altmark, Germany during the period 1996 to 1997. Phosphorus contained in geese excrement on the ice was measured in the winters 1996 and 1997.In February 1996 (after 9 days of frozen lake surface) two excrement fields amounted to 80 ha and 30 ha in area and in January 1997, 10 days after ice closure, the excrement field was 106 ha large. The weight of excrement was estimated to be 148 to 266 g m−2 fresh weight (mean 201 g m−2) in 1996 and 83 g m−2 to 408 g m−2 (mean of 243 g m−2) in 1997. The average of phosphorus content was 8.5 mg g−1 dry weight in 1997 and 9.2 mg g−1 in 1996. Based on these values the phosphorus input attributed to nordic geese was calculated. Our results demonstrated a phosphorus import in 1996 after 9 days of frozen lake surface of 251 kg and in 1997 after 10 days of freezing of 173 kg. During 100 days of wintering, the nordic geese on Lake Arendsee produced a phosphorus load of 2.8 t in 1996 and 1.7 t in 1997. Compared with the annual phosphorus import from different sources, the contribution by nordic geese was 88 % in 1996 and 92 % in 1997. Its yearly phosphorus load during the winter months appears as a significant eutrophication factor for the trophic level of Lake Arendsee. However, the annual external load is approximately 10 % of the phosphorus poolsize in the lake water, and even less when considering the amount lodged in the bottom sediments. %0 conference lecture %@ %A Colijn, F., Haese, C., Schroeder, F., Riethmueller, R. %D 2008 %J 9th International Conference LITTORAL 2008, A Changing Coast: Challenge for the Environmental Policies %T Coastal observatories: observation, modelling and analysis of global change in coastal waters %U %X %0 journal article %@ 0024-3590 %A Wiltshire, K.H., Malzahn, A.M., Wirtz, K.W., Greve, W., Janisch, S., Mangelsdorf, P., Manly, B.F.J., Boersma, M. %D 2008 %J Limnology and Oceanography %N 4 %P 1294-1302 %R doi:10.4319/lo.2008.53.4.1294 %T Resilience of North Sea phytoplankton spring bloom dynamics: An analysis of long-term data at Helgoland Roads %U https://doi.org/10.4319/lo.2008.53.4.1294 4 %X Analyzing one of the most extensive long-term data series in the North Sea, the Helgoland Roads time series, we investigated the changes in the factors that potentially drive phytoplankton bloom dynamics in the German Bight. We compared the changes in these factors with the changes in the spring bloom phenology. We combined zooplankton, nutrient, weather, and phytoplankton data to analyze whether there has been a shift in trophic interactions in the North Sea affecting the spring bloom timing. The potential influence of temperature, with a mean increase of 1.5°C, was investigated. We showed that the German Bight around Helgoland is a highly dynamic system and has undergone considerable change in the last 30 yr. Nutrient levels, temperature, underwater light climate and wind speed have all changed. However, the spring bloom dynamics have hardly changed at all. We showed that the spring bloom tends to come later in warmer years but that this is not directly correlated with the overall warming trend. The known regime shift of the late 1980s is clearly visible in our data in terms of average phytoplankton winter densities and average cell size, but even so the start of the spring bloom has not changed. %0 conference lecture %@ %A Sedlacek, S., Ziemer, F., Cysewski, M. %D 2008 %J 2. Hamburger Kuestensymposium %T Flaechendeckende Abschaetzung der stroemungsbedingten Bodenschubspannungen im Flachwasser auf Basis von Radarmessungen %U %X %0 conference lecture %@ %A Mueller, J.-M., Riethmueller, R., Onken, R. %D 2008 %J 31st International Conference on Coastal Engineering %T Multiple Time Scale Analysis of Suspended Sediment Concentration in the Wadden Sea %U %X %0 book part %@ %A Horstmann, J., Koch, W. %D 2008 %J Remote Sensing of the European Seas %P 331-342 %R doi:10.1007/978-1-4020-6772-3_25 %T High Resolution Wind Field Retrieval from Synthetic Aperture Radar: North Sea Examples %U https://doi.org/10.1007/978-1-4020-6772-3_25 %X A methodology for retrieving high resolution ocean surface wind fields from satellite borne Synthetic Aperture Radar (SAR) data is introduced and validated. The algorithm is applicable to SAR data acquired at C-band at moderate incidence angles. Wind directions are extracted from wind induced streaks that are visible in SAR images and that are very well aligned with the mean surface wind direction. To extract the orientation of these streaks an algorithm based on the derivation of local gradients is utilized. Ocean surface wind speeds are derived from the Normalized Radar Cross Section (NRCS) using a geophysical model function that describes the dependency of the NRCS on the wind and imaging geometry. To validate the algorithm and demonstrate its applicability, SAR retrieved wind fields of the North Sea are compared to numerical atmospheric model results of the German Weather Service. %0 journal article %@ 0196-2892 %A Senet, C.M., Seemann, J., Flampouris, S., Ziemer, F. %D 2008 %J IEEE Transactions on Geoscience and Remote Sensing %N 8 %P 2267-2279 %R doi:10.1109/TGRS.2008.916474 %T Determination of Bathymetric and Current Maps by the Method DiSC Based on the Analysis of Nautical X-Band Radar Image Sequences of the Sea Surface (November 2007) %U https://doi.org/10.1109/TGRS.2008.916474 8 %X Morphodynamic processes in coastal areas are affected by tidal currents and sea state. The continuous observation of near coastal areas is important in order to monitor dangerous current-regime and bathymetry changes. Therefore, there is an urgent need for remote sensing techniques delivering the important hydrographic parameters with a high spatial resolution. Dispersive surface classificator (DiSC) is a newly developed method based on the analysis of nautical X-band radar image sequences of sea surface waves to determine spatial maps of hydrographic parameters, e.g., spatial maps of the bathymetry and the ocean current field. The method DiSC is described and is illustrated by the presentation of results based on a dataset acquired with a ground-based X-band radar installation mounted on the Island of Sylt in the German Bight. The calculated bathymetric maps are verified by multibeam echo sounder observations. %0 journal article %@ 0168-2563 %A Beck, M., Dellwig, O., Holstein, J.M., Grunwald, M., Liebezeit, G., Schnetger, B., Brumsack, H.-J. %D 2008 %J Biogeochemistry %N 2 %P 221-238 %R doi:10.1007/s10533-008-9215-6 %T Sulphate, dissolved organic carbon, nutrients and terminal metabolic products in deep pore waters of an intertidal flat %U https://doi.org/10.1007/s10533-008-9215-6 2 %X This study addresses deep pore water chemistry in a permeable intertidal sand flat at the NW German coast. Sulphate, dissolved organic carbon (DOC), nutrients, and several terminal metabolic products were studied down to 5 m sediment depth. By extending the depth domain to several meters, insights into the functioning of deep sandy tidal flats were gained. Despite the dynamic sedimentological conditions in the study area, the general depth profiles obtained in the relatively young intertidal flat sediments of some metres depth are comparable to those determined in deep marine surface sediments. Besides diffusion and lithology which control pore water profiles in most marine surface sediments, biogeochemical processes are influenced by advection in the studied permeable intertidal flat sediments. This is supported by the model setup in which advection has to be implemented to reproduce pore water profiles. Water exchange at the sediment surface and in deeper sediment layers converts these permeable intertidal sediments into a “bio-reactor” where organic matter is recycled, and nutrients and DOC are released. At tidal flat margins, a hydraulic gradient is generated, which leads to water flow towards the creekbank. Deep nutrient-rich pore waters escaping at tidal flat margins during low tide presumably form a source of nutrients for the overlying water column in the study area. Significant correlations between the inorganic products of terminal metabolism (NH4 + and PO4 3−) and sulphate depletion suggest sulphate reduction to be the dominant pathway of anaerobic carbon remineralisation. Pore water concentrations of sulphate, ammonium, and phosphate were used to elucidate the composition of organic matter degraded in the sediment. Calculated C:N and C:P ratios were supported by model results. %0 conference object %@ %A Schartau, M., Engel, A., Colijn, F. %D 2008 %J Incorporating microbial dynamics in studies of shelf ecosystems, ICES 2008 Annual Science Conference %P 81-82 %T Transformation of dissolved organic matter and its diverse effect on higher trophic level %U %X %0 journal article %@ 0012-821X %A Mohtadi, M., Rossel, P., Lange, C.B., Pantoja, S., Boening, P., Repeta, D.J., Grunwald, M., Lamy, F., Hebbeln, D., Brumsack, H.-J. %D 2008 %J Earth and Planetary Science Letters %N 1-2 %P 221-230 %R doi:10.1016/j.epsl.2008.04.043 %T Deglacial pattern of circulation and marine productivity in the upwelling region off central-south Chile %U https://doi.org/10.1016/j.epsl.2008.04.043 1-2 %X A high-resolution sea surface temperature and paleoproductivity reconstruction on a sedimentary record collected at 36°S off central-south Chile (GeoB 7165-1, 36°33′S, 73°40′W, 797 m water depth, core length 750 cm) indicates that paleoceanographic conditions changed abruptly between 18 and 17 ka. Comparative analysis of several cores along the Chilean continental margin (30°–41°S) suggests that the onset and the pattern of deglacial warming was not uniform off central-south Chile due to the progressive southward migration of the Southern Westerlies and local variations in upwelling. Marine productivity augmented rather abruptly at 13–14 ka, well after the oceanographic changes. We suggest that the late deglacial increase in paleoproductivity off central-south Chile reflects the onset of an active upwelling system bringing nutrient-rich, oxygen-poor Equatorial Subsurface Water to the euphotic zone, and a relatively higher nutrient load of the Antarctic Circumpolar Current. During the Last Glacial Maximum, when the Southern Westerlies were located further north, productivity off central-south Chile, in contrast to off northern Chile, was reduced due to direct onshore-blowing winds that prevented coastal upwelling and export production. %0 GKSS report %@ %A Bernem, K.-H.van, Doerffer, R., Grohnert, A., Heymann, K., Kleeberg, U., Krasemann, H., Reichert, J., Reichert, M., Schiller, H. %D 2007 %J %T Sensitivitaetsraster Deutsche Nordseekueste II - Aktualisierung und Erstellung eines operationellen Modells zur Vorsorgeplanung bei der Oelbekaempfung %U %X %0 journal article %@ 0167-6369 %A Schiller, H., Schoenfeld, W., Krasemann, H., Schiller, K. %D 2007 %J Environmental Monitoring and Assessment %N 1-3 %P 339-350 %R doi:10.1007/s10661-006-9538-5 %T Novelty Detection – Recognition and Evaluation of Exceptional Water Reflectance Spectra %U https://doi.org/10.1007/s10661-006-9538-5 1-3 %X The aim of environmental surveillance is to monitor known phenomena as well as to detect exceptional situations. Synoptic monitoring of large areas in coastal waters can be performed by remote sensing using multispectral sensors onboard satellites. Many methods are in use which enable the detection and quantification of ‘standard algae’ or specific algae blooms using their known spectral response. The present study focusses on the detection of spectra outside the known range and which are referred to as exceptional spectra. In a first step observations from a one-year period were used to establish the parameterisation of what is defined as ‘normal.’ In a second step observations from a different period were used to test the novelty detection application, i.e. to look for features not occurring in the first period. %0 journal article %@ 0893-6080 %A Schiller, H. %D 2007 %J Neural networks %N 4 %P 479-483 %R doi:10.1016/j.neunet.2007.04.022 %T Model inversion by parameter fit using NN emulating the forward model - Evaluation of indirect measurements %U https://doi.org/10.1016/j.neunet.2007.04.022 4 %X This paper shows how NNs can be used to improve inversion accuracy by minimizing the sum of error squares. The procedure is very fast as it takes advantage of the Jacobian which is a byproduct of the NN calculation. An example from remote sensing is shown. It is also possible to take into account a non-diagonal covariance matrix of the measurement to derive the covariance matrix of the retrieved parameters. %0 conference poster %@ %A Flampouris, S., Ziemer, F., Seemann, J. %D 2007 %J International Geoscience and Remote Sensing Symposium 2007 %T Survey of bathymetry and current fields by radar image series acquired by shore based x-band radar %U %X %0 journal article %@ 0143-1161 %A Schroeder, Th., Behnert, I., Schaale, M., Fischer, J., Doerffer, R. %D 2007 %J International Journal of Remote Sensing %N 7 %P 1469-1486 %R doi:10.1080/01431160600962574 %T Atmospheric correction algorithm for MERIS above case‐2 waters %U https://doi.org/10.1080/01431160600962574 7 %X The development and validation of an atmospheric correction algorithm designed for the Medium Resolution Imaging Spectrometer (MERIS) with special emphasis on case‐2 waters is described. The algorithm is based on inverse modelling of radiative transfer (RT) calculations using artificial neural network (ANN) techniques. The presented correction scheme is implemented as a direct inversion of spectral top‐of‐atmosphere (TOA) radiances into spectral remote sensing reflectances at the bottom‐of‐atmosphere (BOA), with additional output of the aerosol optical thickness (AOT) at four wavelengths for validation purposes. The inversion algorithm was applied to 13 MERIS Level1b data tracks of 2002–2003, covering the optically complex waters of the North and Baltic Sea region. A validation of the retrieved AOTs was performed with coincident in situ automatic sun–sky scanning radiometer measurements of the Aerosol Robotic Network (AERONET) from Helgoland Island located in the German Bight. The accuracy of the derived reflectances was validated with concurrent ship‐borne reflectance measurements of the SIMBADA hand‐held field radiometer. Compared to the MERIS Level2 standard reflectance product generated by the processor versions 3.55, 4.06 and 6.3, the results of the proposed algorithm show a significant improvement in accuracy, especially in the blue part of the spectrum, where the MERIS Level2 reflectances result in errors up to 122% compared to only 19% with the proposed algorithm. The overall mean errors within the spectral range of 412.5–708.75 nm are calculated to be 46.2% and 18.9% for the MERIS Level2 product and the presented algorithm, respectively. %0 journal article %@ 0272-7714 %A Lanuru, M., Riethmueller, R., Bernem, K.-H.van, Heymann, K. %D 2007 %J Estuarine, Coastal and Shelf Science %N 4 %P 603-617 %R doi:10.1016/j.ecss.2006.11.009 %T The effect of bedforms (crest and trough systems) on sediment erodibility on a back-barrier tidal flat of the East Frisian Wadden Sea, Germany %U https://doi.org/10.1016/j.ecss.2006.11.009 4 %X Two different processes were identified for the difference in erodibility between crests and troughs: (1) At stations with emersion times less than 6 h, the higher benthic diatom biomass (measured as chlorophyll a concentration) on the crests increases the amount of EPS, which is likely to stabilize the sediment surface of these features; (2) in a saltmarsh transition area (most landward station), physical processes such as surface drying and compaction seem to enhance in a synergistic way the sediment stability on the crests. %0 journal article %@ 0143-1161 %A Doerffer, R., Schiller, H. %D 2007 %J International Journal of Remote Sensing %N 3-4 %P 517-535 %R doi:10.1080/01431160600821127 %T The MERIS Case 2 Water Algorithm %U https://doi.org/10.1080/01431160600821127 3-4 %X The bio-optical model used for the simulations is based on a large data set collected mainly in European waters. One special feature is the combination of a forward NN and a backward NN, which allows testing if the measured spectrum is within the scope of the training set. The comparison with independent test data sets, in situ observations and with the case 1 water algorithm used for MERIS show a good agreement. %0 journal article %@ 1541-5856 %A Roettgers, R., Doerffer, R. %D 2007 %J Limnology and Oceanography: Methods %P 126-135 %T Measurements of optical absorption by chromophoric dissolved organic matter using a point-source integrating-cavity absorption meter %U %X The light absorption of 0.22-µm filtered seawater samples from the North Sea and the Atlantic Ocean was measured by a point-source integrating-cavity absorption meter (PSICAM) and the results compared to measurement in a spectrophotometer. The absorption coefficient of this Gelbstoff or chromophoric dissolved organic matter (CDOM) range from high values of 0.103 to 0.519 m-1 at 442 nm for samples from the North Sea to very low values of 0.004 to 0.046 m-1 for samples from the Atlantic Ocean. At these low values the influence of sample temperature and salinity on water absorption was significant. Hence, instrument-specific temperature and salinity coefficients were determined and subsequently used for correcting absorption data. Spectrophotometrically determined absorption was significantly higher at shorter wavelengths (<442 nm) than absorption measured by the PSICAM, probably showing a significant influence of scattering by small particles remaining in the sample after filtration. At wavelengths between 442 and 500 nm the correlation of PSICAM and spectrophotometer followed the 1:1 correspondence, whereas at longer wavelengths the absorption was below the detection limit of the spectrophotometer. A similar agreement was obtained for the exponential slope of the CDOM absorption. The PSICAM matches the spectrophotometer results but is more sensitive and not affected by scattering, it will improve our ability to determine CDOM absorption in oligotrophic waters for the visible light spectral region. %0 journal article %@ 1463-9246 %A Frank, C., Schroeder, F. %D 2007 %J Journal of Automated Methods and Management in Chemistry %P 49535 %R doi:10.1155/2007/49535 %T Using sequential injection analysis to improve system and data reliability of on-line methods: Determination of ammonium and phosphate in coastal waters %U https://doi.org/10.1155/2007/49535 %X 0.05 μM. Results from a campaign in summer 2005 are shown. %0 journal article %@ 0169-8095 %A Behnert, I., Matthias, V., Doerffer, R. %D 2007 %J Atmospheric Research %N 3 %P 201-220 %R doi:10.1016/j.atmosres.2006.05.006 %T Aerosol climatology from ground-based measurements for the southern North Sea %U https://doi.org/10.1016/j.atmosres.2006.05.006 3 %X Compared to the standard aerosol models differences in the Ångström wavelength exponent α440−870 , the single scattering albedo and the refractive index are detected. Based on these observations a new aerosol model for the atmospheric correction of coastal water reflectance spectra of the imaging spectrometer MERIS/ENVISAT was set up, which meets in particular the higher Ångström wavelength exponent of the coastal sites compared to standard maritime conditions. %0 conference lecture %@ %A Loebl, M., Colijn, F., Beusekom, J.van, Baretta-Bekker, J.G., Lancelot, C., Philippart, C.J.M., Wiltshire, K.H. %D 2007 %J Comparative Analyses of Phytoplankton Dynamics on Regional to Global Scales, Chapman Conference on Long Time-Series Observations in Coastal Ecosystems %T Limitation of phytoplankton growth - Differences and Similarities along the North European continental coast %U %X %0 journal article %@ 0025-3154 %A Fonfara, S., Siebert, U., Prange, A., Colijn, F. %D 2007 %J Journal of the Marine Biological Association of the United Kingdom %P 305-311 %R doi:10.1017/S0025315407055567 %T The impact of stress on cytokine and haptoglobin mRNA expression in blood samples from harbour porpoises (Phocoena phocoena) %U https://doi.org/10.1017/S0025315407055567 %X Cytokines are important cell mediators involved in immune responses. Their expression can be modulated by numerous factors, including stress. The aim of this study was to compare cytokine mRNA expression from harbour porpoises exposed to different environments. Blood samples were taken from two healthy porpoises living in captivity at the Fjord and Belt Centre Kerteminde, Denmark, and from four wild porpoises accidentally caught in Danish waters. Real-time RT-PCR was used to quantify the transcription of interleukin-(IL)-1β, IL-2, -4, -6, -10, tumour necrosis factor-(TNF)-α, transforming growth factor-(TGF)-β and the acute phase protein haptoglobin. This revealed downregulation of the pro-inflammatory cytokines IL-1β, IL-2, IL-6 and TNFα, and a switch towards the T-helper-cell-(Th)2- and Th3-cytokines, IL-4 and TGFβ, in blood samples of the wild-captured animals. This indicated a shift towards immunomodulatory cytokines. In addition, cortisol levels were increased in the wild-caught porpoises. These results are suggestive of stress-induced modulation of the immune responses in the accidentally caught animals. The current study indicates that the expression pattern of these cytokines and the estimation of the Th1- to Th2- and Th3-cytokine mRNA ratios might be a useful indicator to analyse the influence of stress on the immune system in harbour porpoises. %0 conference lecture %@ %A Krasemann, H., Petersen, W. %D 2007 %J ENVISAT Symposium 2007 %T Synergistic use of Ferrybox and ENVISAT data with the aid of a hydrodynamic transport model %U %X %0 conference lecture %@ %A Schiller, H., Schoenfeld, W., Krasemann, H., Schiller, K. %D 2007 %J ENVISAT Symposium 2007 %T Novelty Detection - Recognition and Evaluation of Exceptional Water Reflectance Spectra %U %X %0 journal article %@ 1541-5856 %A Roettgers, R., Haese, C., Doerffer, R. %D 2007 %J Limnology and Oceanography: Methods %N 1 %P 1-12 %T Determination of the particulate absorption of microalgae using a point-source integrating-cavity absorption meter: verification with a photometric technique %U 1 %X The determination of the spectral light absorption coefficient of planktonic algae in seawater is crucial for many applications, including optical remote sensing. Common techniques are adversely affected by light-scattering effects, or by low particle concentrations in situ. Measurements with a point-source integrating-cavity absorption meter (PSICAM) can overcome both difficulties. In our study, we assessed the performance of a PSICAM for measuring the absorption coefficients of microalgae by a comparison with state-of-the-art techniques. The PSICAM was evaluated by comparative measurements of diluted algal cultures with a photometric setup, where the sample cuvette is placed in the center of an integrating sphere (CIS). The accuracy of both the CIS and the PSICAM technique was calibrated against a commercial spectrophotometer by measurements of dense algal cultures. The remaining sources of error for the PSICAM technique were the bleaching procedure and chlorophyll fluorescence. We propose an improved bleaching technique and introduce a correction procedure for the fluorescence effects. Applying both, the overall differences between PSICAM and CIS measurements were less than ± 1%. We further demonstrate that the accuracy of the PSICAM is at least as good as that of a commercial spectrophotometer, but its precision should be two to three orders of magnitude higher. Due to its high sensitivity and accuracy, and to the fact that sources of error can be identified and accounted for, the PSICAM has a great potential to significantly improve the determination of absorption spectra of particulate matter in natural seawater. %0 review %@ 0028-1301 %A Colijn, F. %D 2007 %J Natur und Museum %N 1-2 %P 38 %T Review: Senckenbergiana maritima, Baende 33 und 34 %U 1-2 %X No abstract %0 doctoral thesis %@ %A Frank, C. %D 2007 %J %T Entwicklung und Validierung schneller Methoden zur Bestimmung von Naehrstoffen im Kuestenbereich und deren Anwendung zur Quantifizierung der Naehrstoffgradienten im Wattenmeer (Dissertation) %U %X %0 journal article %@ 0278-4343 %A Onken, R., Callies, U., Vaessen, B., Riethmueller, R. %D 2007 %J Continental Shelf Research %N 12 %P 1656-1676 %R doi:10.1016/j.csr.2007.01.029 %T Indirect determination of the heat budget of tidal flats %U https://doi.org/10.1016/j.csr.2007.01.029 12 %X can be used to determine the integral bottom heat flux of the tidal flats. %0 GKSS report %@ %A Bernem, K.-H.van, Fleischmann, J., Krasemann, H., Krueger, D., Luebbe, T.-P. %D 2007 %J %T Sensitivitaetskartierung zur Oelbekaempfung an den Unterlaeufen von Eider, Elbe, Weser und Ems %U %X %0 conference paper %@ %A Cysewski, M.-C., Schymura, G., Ziemer, F. %D 2007 %J Geoinformationen fuer die Kuestenzone, Beitraege des 1. Hamburger Symposiums %P 2-11 %T Hochaufloesende und flaechenhafte Vermessungen von Oberflaechenstroemungen mit einem Dopplerisierten Radar %U %X %0 conference lecture %@ %A Riethmueller, R., Simons, D., Snellen, M., Heineke, M., Vorberg, R., Ysebaert, T. %D 2007 %J Underwater Acoustics Measurements 2007 %T Area-wide mapping of submarine habitats in shallow waters by combining acoustical multi-beam seabed classification with video imaging ground truth %U %X %0 conference lecture %@ %A Loebl, M., Colijn, F., Martens, P., Beusekom, J.E.E.van %D 2007 %J Long-Term Change in the Northern Wadden Sea, Workshop %T Long-Term phytoplankton dynamics in the Northern Wadden Sea %U %X %0 conference lecture %@ %A Colijn, F., Loebl, M., Beusekom, J.van %D 2007 %J IMBER/LOICZ Continental Margins Open Science Conference %T Long term eutrophication trends along the NW European continental coast %U %X %0 journal article %@ 1439-4227 %A Wichard, T., Gerecht, A., Boersma, M., Poulet, S.A., Wiltshire, K.H., Pohnert, G. %D 2007 %J ChemBioChem - A European Journal of Chemical Biology %N 10 %P 1146-1153 %R doi:10.1002/cbic.200700053 %T Lipid and fatty acid composition of Diatoms revisited: Rapid wound activated change of food quality parameters influences herbivore success %U https://doi.org/10.1002/cbic.200700053 10 %X Lipid and fatty acid composition are considered to be key parameters that determine the nutritive quality of phytoplankton diets for zooplanktonic herbivores. The fitness, reproduction and physiology of the grazers are influenced by these factors. The trophic transfer of lipids and fatty acids from algal cells has been typically studied by using simple extraction and quantification approaches, which, as we argue here, do not reflect the actual situation in the plankton. We show that cell disruption, as it occurs during a predator's grazing on diatoms can drastically change the lipid and fatty acid content of the food. In some algae, a rapid depletion of polyunsaturated fatty acids (PUFAs) is observed within the first minutes after cell disruption. This fatty acid depletion is directly linked to the production of PUFA-derived polyunsaturated aldehydes (PUA); these are molecules that are thought to be involved in the chemical defence of the algae. PUA-releasing diatoms are even capable of transforming lipids from other sources if these are available in the vicinity of the wounded cells. Fluorescent staining reveals that the enzymes involved in lipid transformation are active in the foregut of copepods, and therefore link the depletion processes directly to food uptake. Incubation experiments with the calanoid copepod Temora longicornis showed that PUFA depletion in PUA-producing diatoms is correlated to reduced hatching success, and can be compensated for by externally added single fatty acids. %0 journal article %@ 0739-0572 %A Dankert, H., Horstmann, J. %D 2007 %J Journal of Atmospheric and Oceanic Technology %N 9 %P 1629-1642 %R doi:10.1175/JTECH2083.1 %T A Marine Radar Wind Sensor %U https://doi.org/10.1175/JTECH2083.1 9 %X A new method for retrieving the wind vector from radar-image sequences is presented. This method, called WiRAR, uses a marine X-band radar to analyze the backscatter of the ocean surface in space and time with respect to surface winds. Wind direction is found using wind-induced streaks, which are very well aligned with the mean surface wind direction and have a typical spacing above 50 m. Wind speeds are derived using a neural network by parameterizing the relationship between the wind vector and the normalized radar cross section (NRCS). To improve performance, it is also considered how the NRCS depends on sea state and atmospheric parameters such as air–sea temperature and humidity. Since the signal-to-noise ratio in the radar sequences is directly related to the significant wave height, this ratio is used to obtain sea state parameters. All radar datasets were acquired in the German Bight of the North Sea from the research platform FINO-I, which provides environmental data such as wind measurements at different heights, sea state, air–sea temperatures, humidity, and other meteorological and oceanographic parameters. The radar-image sequences were recorded by a marine X-band radar installed aboard FINO-I, which operates at grazing incidence and horizontal polarization in transmit and receive. For validation WiRAR is applied to the radar data and compared to the in situ wind measurements from FINO-I. The comparison of wind directions resulted in a correlation coefficient of 0.99 with a standard deviation of 12.8°, and that of wind speeds resulted in a correlation coefficient of 0.99 with a standard deviation of 0.41 m s−1. In contrast to traditional offshore wind sensors, the retrieval of the wind vector from the NRCS of the ocean surface makes the system independent of the sensors’ motion and installation height as well as the effects due to platform-induced turbulence. %0 conference lecture (invited) %@ %A Colijn, F., Kremer, H. %D 2007 %J Joint Meeting 3rd European Conference on Lagoon Research and 1st Congress Lagunet %T LOICZ and the Water Framework Directive in the international Wadden Sea %U %X %0 conference poster %@ %A Mueller, J.-M., Riethmueller, R., Onken, R. %D 2007 %J 9th International Conference on Nearshore and Estuarine Cohesive Sediment Transport Processes, Intercoh 2007 %T Impact of wind parameters on suspended sediment concentration %U %X %0 conference lecture %@ %A Breitbach, G. %D 2007 %J SSE Workshop der ESA %T InterRisk %U %X %0 journal article %@ 0142-7873 %A Becker, C., Boersma, M. %D 2007 %J Journal of Plankton Research %N 5 %P 463-470 %R doi:10.1093/plankt/fbm030 %T Effects of essential fatty acids on the reproduction of a generalist herbivore %U https://doi.org/10.1093/plankt/fbm030 5 %X We studied direct and indirect effects of essential fatty acids (EFA) on Daphnia magna reproduction. Daphnia females that received EFA enriched algae over their entire lifespan produced larger broods than females fed control algae. However, EFA-enriched females were also 91% heavier than control females, which potentially explain the larger investment in reproduction. Thus, with such a large difference in female mass, it is difficult to differentiate the direct effect of the EFA addition from the indirect (maternal size) effects on reproduction. To assess the direct effects on reproduction, we performed two experiments in which we enriched female diets with a range of fatty acids. To minimize maternal size differences, we applied the EFA enrichments only to mature daphniids and studied the effects on reproduction during and after two time intervals (15–16 and 7 days). Limiting the enrichment phase until after maturity decreased the maternal size differences over the enrichment phase among the fatty acid treatments from an average of 91% (for life time enrichment) to 29% after 15–16 days maternal enrichment interval, to 18% after the 7 day interval. Minimizing size differences between differently enriched females decreased the differences in brood size and offspring size. Neonates from control females were more severely affected by starvation than offspring from females that received saturated and polyunsaturated fatty acid enrichments. Under low food concentrations, only neonates that had access to polyunsaturated fatty acids had positive growth rates, thus showing that although dietary fatty acids can be used for energy purposes, specific fatty acids are required to build new biomass. One consequence of our findings is that offspring size does not serve as a good estimate of offspring quality when feeding on different resource qualities. %0 conference lecture (invited) %@ %A Colijn, F., Petersen, W., Schroeder, F., Kaitala, S., Soerensen, K., Hydes, D. %D 2007 %J Fourth Session of the Ship Observations Team (SOT-IV) at WMO Headquarters %T FerryBox and Automated Ships of Opportunity as Operational Tools for Ocean Observing Tasks %U %X %0 conference lecture %@ %A Colijn, F. %D 2007 %J NATTE WAD, Expertbijeenkomst %T Wadden Sea Research in general and specifically in Germany %U %X %0 conference lecture %@ %A Ziemer, F., Cysewski, M. %D 2006 %J 2006 IEEE International Geoscience & Remote Sensing Symposium %T High Resolution Sea Surface Current Maps produced by Scanning with Ground Based Doppler Radar %U %X %0 conference lecture %@ %A Jordi, A., Vizoso, G., Orfila, A., Basterretxea, G., Casas, B., Ruiz, M., Garau, B., Alvarez, A., Alvarez, E., Rodriguez, I., Onken, R., Tintore, J. %D 2006 %J EGU-Conference 2006 %T Sub-basin scale operational system in the Balearic Sea %U %X %0 conference lecture (invited) %@ %A Colijn, F. %D 2006 %J 20 Jahre Nationalpark Niedersaechsisches Wattenmeer - wissenschaftliche Beitraege fuer einen zukunftsweisenden Naturschutz %T Kuestenmanagement: Miteinander, nicht gegeneinander %U %X %0 conference lecture (invited) %@ %A Colijn, F. %D 2006 %J Open Meeting on Physical Measurements for Ecosystem Requirements %T Operational oceanography - Status, achievements and perspectives %U %X %0 conference lecture %@ %A Fonfara, S., Siebert, U., Prange, A., Colijn, F. %D 2006 %J 37th Annual IAAAM Conference, International Association for Aquatic Animal Medicine %T Variations of Cytokine Expression and the Impact of Stress and Infection in Harbour Seals (Phoca Vitulina) of the North Sea %U %X %0 conference lecture (invited) %@ %A Colijn, F., Emeis, K.-C. %D 2006 %J Eutrophierung: Naehrstoffeintraege in die Ostsee, ihre Wirkungen sowie moegliche Gegenmaßnahmen, Oeffentliche Anhoerung %T Naehrstoffeintraege in und Reduktionsszenarien fuer die Ostsee, Stickstoffverbindungen %U %X %0 conference lecture %@ %A Schiller, H. %D 2006 %J International Joint Conference on Neural Networks %T Model Inversion by Parameter Fit Using NN Emulating the Forward Model - Evaluation of Indirect Measurements %U %X %0 conference lecture %@ %A Colijn, F., Petersen, W., Wehde, H., Schroeder, F. %D 2006 %J ICES Annual Science Conference 2006 %T Automated Measuring System for Monitoring of Coastal Waters: Synthesis of Results of the EU funded FerryBox Project %U %X %0 conference paper %@ %A Colijn, F., Garthe, S. %D 2006 %J Monitoring and Assessment in the Wadden Sea, Proceedings from the 11. Scientific Wadden Sea Symposium, NERI Technical Report No. 573, Part I %P 13-20 %T EU Directives and their effects on the ecosystem of the Wadden Sea %U %X %0 conference lecture %@ %A Colijn, F. %D 2006 %J Statuskonferenz des BMBF-Verbundes Zukunft Kueste - Coastal Futures %T Fachuebergreifende Forschung und Planungspraxis - eine Herausforderung %U %X %0 journal article %@ 1616-7341 %A Schiller, K. %D 2006 %J Ocean Dynamics %N 2 %P 79-85 %R doi:10.1007/s10236-006-0058-1 %T Derivation of Photosynthetically Available Radiation from METEOSAT data in the German Bight with Neural Nets %U https://doi.org/10.1007/s10236-006-0058-1 2 %X Two different models, a Physical Model and a Neural Net (NN), are used for the derivation of the Photosynthetically Available Radiation (PAR) from METEOSAT data in the German Bight; advantages and disadvantages of both models are discussed. The use of a NN for derivation of PAR should be preferred to the Physical Model because by construction, a NN can take the various processes determining PAR on a surface much better into account than a non-statistical model relying on averaged relations. %0 conference lecture %@ %A Breitbach, G. %D 2006 %J Kolloquium des Instituts fuer Kuestenforschung %T Aenderungen im Publikationswesen %U %X %0 journal article %@ 0039-9140 %A Frank, C., Schroeder, F., Ebinghaus, R., Ruck, W. %D 2006 %J Talanta %N 3 %P 513-517 %R doi:10.1016/j.talanta.2005.12.055 %T Using sequential injection analysis for fast determination of phosphate in coastal waters %U https://doi.org/10.1016/j.talanta.2005.12.055 3 %X A sequential injection analysis system (SIA) is described which is suited for the fast determination of filterable molybdate reactive phosphate (FRP, 0.2 μm) in coastal waters. It processes up to 270 samples per hour with a detection limit (3σ) of 0.05 μM and is used for surface mapping of phosphate in areas with steep concentration gradients like the Wadden Sea. The determination is based on the reaction of phosphate with acidic molybdate to phosphomolybdate, which builds non-fluorescent ion pairs with rhodamine 6G. The remaining rhodamine fluorescence is detected at 550 nm with an excitation at 470 nm. Syringe pump, valve and detector were controlled by a self made python programme, which was optimised for high speed SIA measurements in monitoring applications. %0 conference lecture %@ %A Cysewski, M.-C., Schymura, G., Ziemer, F. %D 2006 %J Geoinformationen fuer die Kuestenzone, 1. Hamburger Symposium %T Hochaufloesende und flaechenhafte Vermessungen von Oberflaechenstroemungen mit einem Dopplerisierten Radar %U %X %0 journal article %@ 0025-326X %A Jordi, A., Ferrer, M.I., Vizoso, G., Orfila, A., Basterretxea, G., Alvarez, A., Roig, D., Garau, B., Martinez, M., Fernandez, V., Fornes, A., Ruiz, M., Fornos, J.J., Balaguer, P., Duarte, C.M., Rodriguez, I., Alvarez, E., Onken, R., Orfila, P., Tintore, J. %D 2006 %J Marine Pollution Bulletin %N 5-7 %P 361-368 %R doi:10.1016/j.marpolbul.2005.10.008 %T Scientific management of Mediterranean coastal zone: A hybrid ocean forecasting system for oil spill and search and rescue operations %U https://doi.org/10.1016/j.marpolbul.2005.10.008 5-7 %X The oil spill from Prestige tanker showed the importance of scientifically based protocols to minimize the impacts on the environment. In this work, we describe a new forecasting system to predict oil spill trajectories and their potential impacts on the coastal zone. The system is formed of three main interconnected modules that address different capabilities: (1) an operational circulation sub-system that includes nested models at different scales, data collection with near-real time assimilation, new tools for initialization or assimilation based on genetic algorithms and feature-oriented strategic sampling; (2) an oil spill coastal sub-system that allows simulation of the trajectories and fate of spilled oil together with evaluation of coastal zone vulnerability using environmental sensitivity indexes; (3) a risk management sub-system for decision support based on GIS technology. The system is applied to the Mediterranean Sea where surface currents are highly variable in space and time, and interactions between local, sub-basin and basin scale increase the non-linear interactions effects which need to be adequately resolved at each one of the intervening scales. Besides the Mediterranean Sea is a complex reduced scale ocean representing a real scientific and technological challenge for operational oceanography and particularly for oil spill response and search and rescue operations. %0 conference lecture %@ %A Hydes, D., Bargeron, C.P., Kelly-Gerreyn, B., Wehde, H., Petersen, W., Kaitala, S., Fleming, V., Soerensen, K., Magnusson, J., Lips, I., Lips, U. %D 2006 %J European Operational Oceanography: Present and Future : Proceedings of the 4th EuroGOOS Conference %P 101-107 %T Comparison of eutrophication processes and effects in different European marine areas based on the results of the EU FP-5 FerryBox Project %U %X %0 conference lecture (invited) %@ %A Colijn, F., Beusekom, J.van %D 2006 %J ICES Workshop on Time Series Data relevant to Eutrophication Ecological Quality Objectives, WKEUT %T The role of light and nutrient limitation for the growth of phytoplanktion: long term developments in the Northern German Wadden Sea %U %X %0 conference paper %@ %A Schiller, H. %D 2006 %J 2006 International Joint Conference on Neural Networks %P 8759-8762 %T Model Inversion by Parameter Fit Using NN Emulating the Forward Model - Evaluation of Indirect Measurements %U %X %0 conference lecture %@ %A Colijn, F. %D 2006 %J A new look at the ocean, ESOF 2006, Seminar %T New methods for marine research and monitoring – A chance for science and industry %U %X %0 lecture %@ %A Colijn, F. %D 2006 %J %T Community Ecology %U %X %0 journal article %@ 0026-3672 %A Frank, C., Schroeder, F., Ebinghaus, R., Ruck, W. %D 2006 %J Microchimica Acta %N 1-2 %P 31-38 %R doi:10.1007/s00604-006-0496-y %T A Fast Sequential Injection Analysis System for the Simultaneous Determination of Ammonia and Phosphate %U https://doi.org/10.1007/s00604-006-0496-y 1-2 %X A flow system is described that is based on sequential injection analysis (SIA) and is suitable for the fast determination of ammonia and phosphate in river and marine waters. It is applicable to nutrient mapping in inhomogeneous coastal areas like the Wadden Sea, and was optimised on several cruises on the North Sea. The high sample throughput of 120 samples per analyte per hour and the low reagent consumption (ammonia: 62.5µL; phosphate: 60µL) were achieved using a home made programme written in the python programming language. The determination of free reactive phosphate is based on the reaction of phosphate with acidic molybdate to phosphomolybdate which forms nonfluorescent ion pairs with rhodamine 6G. The remaining rhodamine fluorescence is detected at 550nm with an excitation at 470nm. Ammonia is determined with the help of o-phthaldialdehyde and sodium sulfite. At 85°C and a reaction time of at least one minute a fluorescent species (exc. 365nm, em. 425nm) is formed. The detection limits are (3σ) 0.3µmolL−1 for phosphate and 1µmolL−1 for ammonia. %0 journal article %@ 0093-3651 %A Petersen, W., Schroeder, F., Engelke, C. %D 2006 %J Sea Technology %N 1 %P 53 %T FerryBox - A “Mature” System for Operational Monitoring - Automated Observations of Coastal Waters and Estuaries by Ships of Opportunity %U 1 %X opportunities or coastal/riverine structures (stationary application). %0 report %@ %A Mills, D.K., Walker, P.A., Rees, J.M., Malcolm, S., Fox, C.J., Edwards, M., Laane, R., Bot, P., Ridderinkhof, H., Colijn, F., Petersen, W., Schroeder, F., Wehde, H., Johanneson, J., Svendsen, E., Hackett, B. %D 2006 %J %T Towards a European Marine Ecosystem Observatory (EMECO) %U %X agencies to maximise benefits from operational monitoring programmes (e.g. EuroGOOS, ECOOP GMES). As pressure upon national resources mount and growing awareness of environmental problems with a transboundary nature continues, for example at a catchment level in the Water Framework Directive and for a prospective European marine directive, the need for (international) collaborative regional initiatives have begun to be realised. As the first step towards establishing a wider regional initiative a European Marine Ecosystem Observatory (EMECO) has been established within the North Sea. To develop EMECO (www.cefas.co.uk/emeco) a bottom – up approach has been adopted based upon collaboration between agencies with statutory responsibilities for a range of environmental pressures from monitoring and assessment of nutrients and hazardous substances, wave monitoring to fish stock assessments. The monitoring programmes associated with such activities are by nature long-term and these programmes form key components of EMECO. However, there are a range of other programmes with either a relevant North Sea component (EU Ferry Box programme, International CPR programme, Smart-Buoy programme) or are part of wider initiatives (e.g. satellite remote sensing) that will also contribute to the observatory. It will also embrace initiatives to protect and conserve renewable and sustainable resources such as Marine Protected Areas and closed area for fisheries such as the Dutch Cod Box. The observatory will provide an opportunity to integrate research with monitoring and assessment programmes and to undertake reviews at a regional level to identify gaps in information and develop strategies to address shortcomings. Within the ecosystem approach, ICES is increasingly aware of the need to include ecosystem considerations in its fisheries assessment models in order to enhance their predictive properties. Moreover, ICES’ preparedness to carry out integrated assessments could be greatly enhanced by the scientific framework embedded in EMECO. This paper will describe the approach taken so far with EMECO, will explore the relationships and chances for collaboration with other initiatives (ECOOP GMES, EuroGOOS) and will examine how EMECO might contribute to ICES’ needs for environmental information in fisheries and ecosystem advice. Keywords: ecosystem observatory, monitoring, Ferry Box, Smart-Buoy, remote sensing %0 report %@ %A Wehde, H., Sørensen, K., Schroeder, F., Petersen, W., Loeng, H. %D 2006 %J %T Operational oceanography of the North Sea/Skagerrak and Norwegian Sea by Ferrbox systems: from one line to a coordinated network of Ferryboxes %U %X information. %0 conference poster %@ %A Fonfara, S., Siebert, U., Prange, A., Colijn, F. %D 2005 %J 19th Annual Conference of the European Cetacean Society %T Cytokine expression in blood samples of harbour porpoises: T-helper-(th)-cell cytokines as marker of the health status? %U %X %0 book part %@ %A Colijn, F., Dibbern, M. %D 2005 %J Berichte zur Polar- und Meeresforschung; Die Expeditionen ANTARKTIS XXI-3-4-5 des Forschungsschiffes "Polarstern" 2004 %P 101-104 %T Flow-Cytometry of Phytoplankton during The EIFEX Cruise %U %X %0 conference lecture (invited) %@ %A Breitbach, G. %D 2005 %J GSI Veranstaltung zu Open Access %T Open Access in der HGF %U %X %0 journal article %@ 0003-6935 %A Roettgers, R., Schoenfeld, W., Kipp, P., Doerffer, R. %D 2005 %J Applied Optics %N 26 %P 5549-5560 %R doi:10.1364/AO.44.005549 %T Practical test of a point-source integrating-cavity absorption meter (PSICAM): the performance of different collector assemblies %U https://doi.org/10.1364/AO.44.005549 26 %X the absorption of natural sea water samples at ambient temperatures. %0 journal article %@ 1616-7341 %A Pleskaschevsky, A., Gayer, G., Horstmann, J., Rosenthal, W. %D 2005 %J Ocean Dynamics %N 1 %P 2-9 %R doi:10.1007/s10236-004-0101-z %T Synergy of satellite remote sensing and numerical modeling for monitoring of suspended particulate matter %U https://doi.org/10.1007/s10236-004-0101-z 1 %X Monitoring and modeling of the distribution of suspended particulate matter (SPM) is an important task, especially in coastal environments. Several SPM models have been developed for the North Sea. However, due to waves in shallow water and strong tidal currents in the southern part of the North Sea, this is still a challenging task. In general there is a lack of measurements to determine initial distributions of SPM in the bottom sediment and essential model parameters, e.g., appropriate exchange coefficients. In many satellite-borne ocean color images of the North Sea a plume is visible, which is caused by the scattering of light at SPM in the upper ocean layer. The intensity and length of the plume depends on the wave and current climate. It is well known that the SPM plume is especially obvious shortly after strong storm events. In this paper a quasi-3-D and a 3-D SPM transport model are presented. Utilizing the synergy of satellite-borne ocean color data with numerical models, the vertical exchange coefficients due to currents and waves are derived. This results in models that for the first time are able to reproduce the temporal and spatial evolution of the plume intensity. The SPM models consist of several modules to compute ocean dynamics, the vertical and horizontal exchange of SPM in the water column, and exchange processes with the seabed such as erosion, sedimentation, and resuspension. In the bottom layer, bioturbation via benthos and diffusion processes is taken into account. %0 journal article %@ 0196-2892 %A Schiller, H., Doerffer, R. %D 2005 %J IEEE Transactions on Geoscience and Remote Sensing %N 7 %P 1585-1591 %R doi:10.1109/TGRS.2005.848410 %T Improved Determination of Coastal Water Constituent Concentrations from MERIS Data %U https://doi.org/10.1109/TGRS.2005.848410 7 %X The algorithm to derive the concentrations of coastal (case 2) water constituents from the Medium Resolution Imaging Spectrometer (European Space Agency satellite ENVISAT) is based on neural network (NN) technology. The NN not only transforms water leaving radiance reflectances with high efficiency into concentrations but also checks if its input is in the domain of reflectance spectra which were simulated for the training of the NN. Two NNs are trained with simulated reflectances: (1) invNN to emulate the inverse model (reflectances, geometry) /spl rarr/ concentrations and (2) forwNN to emulate the forward model (concentrations, geometry) /spl rarr/ reflectances. The invNN is used to obtain an estimate of the concentrations. These concentrations are fed into the forwNN, and the derived reflectances are compared with the measured reflectances. Deviations above a threshold are flagged. The paper describes a further improvement: the result obtained by invNN is used as a first guess to start a minimization procedure, which uses the forwNN iteratively to minimize the difference between the calculated reflectances and the measured ones. The procedure is very fast as it takes advantage of the Jacobian which is a byproduct of the NN calculation. %0 journal article %@ 1618-3193 %A Roettgers, R., Colijn, F., Dibbern, M. %D 2005 %J Berichte zur Polar- und Meeresforschung %P 82-87 %T Algal Physiology and Biooptics, Cruise Report ANT XXI/3 „EIFEX“ %U %X Beyond it different techniques were used to follow the photo-physiological changes of the phytoplankton occurring after iron addition and to estimate photosynthesis and primary production. This includes photoacclimation, i.e. effects of solar irradiance, vertical mixing of the water column and water transparency. In addition we were interested in the comparison of different variable chlorophyll fluorescence techniques and in using these different techniques to estimate primary production. %0 conference lecture (invited) %@ %A Cysewski, M.-C., Schymura, G., Ziemer, F. %D 2005 %J 64. DVW-Seminar / 20. Hydrographentag %T Radarscannig als Methode zur Detektion von Oelverschmutzung und ihrer Ausbreitung an der Wasseroberflaeche %U %X %0 conference lecture (invited) %@ %A Colijn, F. %D 2005 %J Institutskolloquium des Instituts fuer Ostseeforschung Warnemuende (IOW) %T Kuestenforschung innerhalb der Helmholtz-Gemeinschaft %U %X %0 conference lecture (invited) %@ %A Staginnus, D., Fabian, H., Colijn, F. %D 2005 %J Warnemuende Turbulence Days %T Effects of small scale turbulence on growth of phytoplankton species %U %X %0 conference lecture %@ %A Petersen, W., Colijn, F., Dunning, J., Hydes, D., Kaitala, S., Kontoyiannis, H., Lavin, A., Lips, I., Howarth, J., Ridderinkhof, H., Pfeiffer, K., Soerensen, K. %D 2005 %J 4th International Conference on EuroGOOS %T European Ferry Box Project: From Online Oceanographic Measurements to Environmental Information %U %X %0 conference lecture (invited) %@ %A Colijn, F., Garthe, S. %D 2005 %J 11th International Scientific Wadden Sea Symposium: Monitoring and Assessment in the Wadden Sea %T Consequences of EU Directives for the Wadden Sea Ecosystem: Do EU Directives support the Wadden Sea Ecosystem? %U %X %0 conference lecture %@ %A Riethmueller, R., Heineke, M., Vorberg, R., Ysebaert, T. %D 2005 %J 11th Scienctific Wadden Sea Symposium %T Area-wide mapping of subtidal benthic habitats by combining acoustical multi-beam technique with video imaging ground truth %U %X %0 conference lecture (invited) %@ %A Colijn, F. %D 2005 %J BSSSC, Baltic Sea States Subregional Cooperation; Region Skane/Schweden, Seminar %T Perspectives of Marine Research %U %X %0 conference lecture %@ %A Schiller, H., Schoenfeld, W., Krasemann, H., Schiller, K. %D 2005 %J 2nd EARSEL Workshop COASTAL ZONE %T The Search for Exceptional Water Reflectance Spectra %U %X %0 conference lecture %@ %A Braun, N., Cysewski, M., Schymura, G., Ziemer, F. %D 2005 %J The first International Conference of Environmental Science and Technology %T Ship Based Radar Mapping Of Sea Surfaces Covered By Substances %U %X %0 journal article %@ 1350-4827 %A Schneiderhan, T., Lehner, S., Schulz-Stellenfleth, J., Horstmann, J. %D 2005 %J Meteorological Applications %N 2 %P 101-110 %R doi:10.1017/S1350482705001659 %T Comparison of offshore wind park sites using SAR wind measurement techniques %U https://doi.org/10.1017/S1350482705001659 2 %X Wind farming has grown rapidly in Europe during the last decade. All European countries with shallow coastal waters and strong mean wind speeds at the coast are planning or already constructing offshore wind farms. Large parts of the North and Baltic Sea are under investigation as to whether they are suitable for offshore parks. In this paper it is demonstrated how satellite images taken by space borne radar sensors can be used to determine mesoscale wind fields and thus help in the task of planning and operating offshore wind farms. High-resolution synthetic aperture radar (SAR) images acquired by the European remote sensing satellite ERS-2 showing single wind turbines are investigated. The methods for retrieving high-resolution wind fields from SAR images are explained and a statistical comparison of wind speed and wind direction at the two offshore wind park sites in the North Sea, Horns Rev and Butendiek, is given. %0 journal article %@ 0924-7963 %A Onken, R., Robinson, A.R., Kantha, L., Lozano, C.J., Haley, P.J., Carniel, S. %D 2005 %J Journal of Marine Systems %N 1-2 %P 45-46 %R doi:10.1016/j.jmarsys.2004.09.010 %T A Rapid Response Nowcast / Forecast System using Multiply Nested Ocean Models and Distributed Data Systems %U https://doi.org/10.1016/j.jmarsys.2004.09.010 1-2 %X Logistics and results of a real-time modeling effort, which took place in fall 2000 in the waters between Corsica and Italy in the Mediterranean Sea, are presented. The major objective was to nest a high-resolution local version of the Harvard Ocean Prediction System (HOPS) into a coarse resolution Colorado University Princeton Ocean Model (CUPOM) covering the northern part of the Western Mediterranean. Due to the different designs of CUPOM and HOPS, traditional nesting methods were not successful. Therefore, a new method was developed that assimilated the CUPOM prognostic fields into HOPS instead of prescribing them only along the open boundaries. Another objective of the effort was to set up and test a data distribution system, providing Internet-based rapid data transfer among the project partners being partly at sea and partly on land in different continents. It is shown that such a system works, enabling turnaround times of less than a day from the time when measurements are taken to the release of the model forecast. %0 journal article %@ 0167-6369 %A Schiller, H., Bernem, K.-H.van, Krasemann, H. %D 2005 %J Environmental Monitoring and Assessment %P 291-299 %R doi:10.1007/s10661-005-8041-8 %T Automated Classification of an Environmental Sensitivity Index %U https://doi.org/10.1007/s10661-005-8041-8 %X seldom field data. %0 journal article %@ 0079-6611 %A Tintore, J., Alvarez, A., Onken, R. %D 2005 %J Progress in Oceanography %N 2-4 %P 87-88 %R doi:10.1016/j.pocean.2005.05.001 %T Mediterranean physical oceanography and biogeochemical cycles: General circulation and climate variability %U https://doi.org/10.1016/j.pocean.2005.05.001 2-4 %X (using observational data and model results) and new evidence for significant inter-annual variability likely related to remote forcing effects such as North Atlantic Oscillation (NAO) has been found. %0 journal article %@ 0094-8276 %A Horstmann, J., Thompson, D.R., Monaldo, F., Iris, S., Graber, H.C. %D 2005 %J Geophysical Research Letters %P L22801 %R doi:10.1029/2005GL023992 %T Can Synthetic Aperture Radars Be Used to Estimate Hurricane Force Winds? %U https://doi.org/10.1029/2005GL023992 %X We compare wind fields retrieved from a RADARSAT-I synthetic aperture radar (SAR) image acquired over Hurricane Ivan on September 10, 2004 using the C-band geophysical model functions Cmod4 and its newest version Cmod5. Cmod4 has previously been shown to yield very good wind field estimates under low and moderate wind conditions. Wind directions obtained from streaks imaged by the SAR, that are well aligned with the mean surface wind direction are used to invert both algorithms to obtain estimates of the wind speed on scales of 1 km. These estimates are compared with predictions from a high-resolution tropical cyclone model as well as local in situ data. It is found that the SAR wind speeds using Cmod5 agree reasonably well, while those from Cmod4 significantly under predict the measured wind speeds near the hurricane eye wall that reach values as high as 60 m s−1. %0 journal article %@ 0364-9059 %A Dankert, H., Horstmann, J., Rosenthal, W. %D 2005 %J IEEE Journal of Oceanic Engineering %N 3 %P 534-542 %R doi:10.1109/JOE.2005.857524 %T Wind- and wave-field measurements using marine X-band radar-image sequences %U https://doi.org/10.1109/JOE.2005.857524 3 %X This paper describes two algorithms for the retrieval of high-resolution wind and wave fields from radar-image sequences acquired by a marine X-band radar. The wind-field retrieval algorithm consists of two parts. In the first part, wind directions are extracted from wind-induced streaks, which are approximately in line with the mean surface wind direction. The methodology is based on the retrieval of local gradients from the mean radar backscatter image and assumes the surface wind direction to be oriented normal to the local gradient. In the second part, wind speeds are derived from the mean radar cross section. Therefore, the dependence of the radar backscatter on the wind vector and imaging geometry has to be determined. Such a relationship is developed by using neural networks (NNs). For the verification of the algorithm, wind directions and speeds from nearly 3300 radar-image sequences are compared to in situ data from a colocated wind sensor. The wave retrieval algorithm is based on a methodology that, for the first time, enables the inversion of marine radar-image sequences to an elevation-map time series of the ocean surface without prior calibration of the acquisition system, and therefore, independent of external sensors. The retrieved ocean-surface elevation maps are validated by comparison of the resulting radar-derived significant wave heights, with the significant wave heights acquired from three colocated in situ sensors. It is shown that the accuracy of the radar-retrieved significant wave height is consistent with the accuracy of the in situ sensors. %0 conference paper %@ %A Petersen, W., Colijn, F., Dunning, J., Hydes, D., Kaitala, S., Kontoyiannis, H., Lavin, A., Lips, I., Howarth, J., Ridderinkhof, H., Pfeiffer, K., Soerensen, K. %D 2005 %J European Operational Oceanography: Present and Future, Proceedings of the 4th International Conference on EuroGOOS %P 551-560 %T European Ferry Box Project: From Online Oceanographic Measurements to Environmental Information %U %X %0 conference lecture %@ %A Fonfara, S., Siebert, U., Prange, A., Colijn, F. %D 2005 %J 33rd Annual Symposium of European Association for Aquatic Mammals %T Influence of infection and stress on cytokine expression in blood samples of harbour porpoises %U %X %0 conference lecture %@ %A Wehde, H., Schroeder, F., Colijn, F., callies, U., Reinke, S., Petersen, W., Schrum, C., Pluess, A., Mills, D. %D 2005 %J 4th International Conference on EuroGOOS %T FerryBox observations in the Southern North Sea – Application of numerical models for improving the significance of the FerryBox data %U %X %0 conference lecture %@ %A Colijn, F. %D 2005 %J GKSS-Jahrestagung %T Durch Beobachtungen das Meer verstehen %U %X %0 conference paper %@ %A Wehde, H., Schroeder, F., Colijn, F., callies, U., Reinke, S., Petersen, W., Schrum, C., Pluess, A., Mills, D. %D 2005 %J European Operational Oceanography: Present and Future, Proceedings of the 4th International Conference on EuroGOOS %P 169-173 %T FerryBox observations in the Southern North Sea – Application of numerical models for improving the significance of the FerryBox data %U %X %0 conference paper %@ %A Braun, N., Cysewski, M., Schymura, G., Ziemer, F. %D 2005 %J Proceedings of Environmental Science and Technology, The Ffirst International Conference %P 614-619 %T Ship Based Radar Mapping Of Sea Surfaces Covered By Substances %U %X %0 conference paper %@ %A Cysewski, M.-C., Schymura, G., Ziemer, F. %D 2005 %J Hydrographie - Vermessung mit Tiefgang, 64. DVW-Seminar / 20. Hydrographentag %P 129-131 %T Radarscannig als Methode zur Detektion von Oelverschmutzung und ihrer Ausbreitung an der Wasseroberflaeche %U %X %0 journal article %@ 0030-3917 %A Behnert, I., Matthias, V., Doerffer, R. %D 2004 %J Optica Pura y Aplicada %N 3 %P 3254-3257 %T Aerosol optical thickness and its spectral dependence derived from sunphotometer measurements over the southern North Sea coastal region %U 3 %X %0 conference paper %@ %A Horstmann, J., Koch, W. %D 2004 %J Coastal and Marine Applications of SAR, Proceedings of the 2nd Workshop, ESA SP-565 %P 61-68 %T High Resolution Ocean Surface Wind Fields Retrieved from Spaceborne Synthetic Aperture Radars Operating at C-Band %U %X %0 conference paper %@ %A Schiller, H., Krasemann, H., Wehde, H. %D 2004 %J 2nd International Workshop on Advanced Environmental Sensing and Monitoring Technologies %P 29-33 %T Application of Autoassociative NN's for Monitoring and for Model Inversion %U %X %0 other %@ %A Petersen, W., Wehde, H. %D 2004 %J Messekatalog der Oceanology International 2004 %T Thinking outside the Box: FerryBox- automatic monitoring of water quality from ferryboats %U %X %0 journal article %@ 0916-8370 %A Tanaka, A., Kishino, M., Doerffer, R., Schiller, H., Oishi, T., Kubota, T. %D 2004 %J Journal of Oceanography %N 3 %P 519-530 %T Development of a Neural Network Algorithm for Retrieving Concentrations of Chlorophyll, Suspended Matter and Yellow Substance from Radiance Data of the Ocean Color and Temperature Scanner %U 3 %X %0 conference paper %@ %A Schneiderhan, T., Schulz-Stellenfleth, J., Lehner, S., Horstmann, J. %D 2004 %J Coastal and Marine Applications of SAR, Proceedings of the 2nd Workshop, ESA SP-565 %N 565 %P 69-74 %T SAR wind fields for offshore wind farming %U 565 %X A technique to measure wind fields with synthetic aperture radar (SAR) and their relevance for offshore wind farming is described. SAR are capable of imaging synoptic wind fields with a coverage of up to 500 km × 500 km, and a resolution of down to 100 m. SAR retrieved wind fields will help in optimal positioning of wind turbines within the wind farms, and investigate the changes of the high-resolution wind fields due to the wind turbines. Satellite borne SAR will improve mesoscale models used for short term power forecast, increase the awareness of wind farmers to use remote sensing data in their planning, and estimate the effects offshore wind farms have on the environment. %0 conference lecture %@ %A Schiller, H., Doerffer, R. %D 2004 %J IGARSS 2004, Science for Society: Exploring and Managing a Changing Planet %T Water Constituents in Case II Waters: Estimates of Concentrations and their Covariances from Meris Data %U %X %0 conference lecture %@ %A Schiller, H., Doerffer, R. %D 2004 %J 24th Symposium of EARSEL, The European Association of Remote Sensing Laboratories %T Improved Determination of Water Constituent Concentrations from Meris Data %U %X %0 conference lecture %@ %A Doerffer, R., Schiller, H. %D 2004 %J IGARSS 2004, Science for Society: Exploring and Managing a Changing Planet %T Fist Test of a Three-stepp Neural Network Inverse Modelling Technique for Retrieval of Water Constituent Concentrations from Case II Water Using Meris Data %U %X %0 conference lecture %@ %A Schiller, H., Krasemann, H., Wehde, H. %D 2004 %J 2nd International Workshop on Advanced Environmental Sensing and Monitoring Technologies %T Application of Autoassociative NN's for Monitoring and for Model Inversion %U %X %0 journal article %@ 1616-7341 %A Horstmann, J., Koch, W., Lehner, S. %D 2004 %J Ocean Dynamics %N 6 %P 570-576 %R doi:10.1007/s10236-004-0098-3 %T Ocean Wind Fields Retrieved from the Advanced Synthetic Aperture Radar Aboard ENVISAT %U https://doi.org/10.1007/s10236-004-0098-3 6 %X In this paper an algorithm is presented which enables high-resolution ocean surface wind fields to be retrieved from the advanced synthetic aperture radar (ASAR) data acquired by the European remote sensing satellite ENVISAT. Wind directions are extracted from wind-induced streaks that are visible in ASAR images at scales above 200 m and that are approximately in line with the mean surface wind direction. Wind speeds are derived from the normalized radar cross section (NRCS) and image geometry of the calibrated ASAR images, together with the local ASAR-retrieved wind direction. Therefore the empirical C-band model CMOD4, which describes the dependency of the NRCS on wind and image geometry, is used. CMOD4 is a semi-empirical model, which was originally developed for the scatterometer of the European remote sensing satellites ERS-1 and 2 operating at C-band with vertical polarization. Consequently, CMOD4 requires modification when applied to ASAR images that were acquired with horizontal polarization in transmitting and receiving. This is performed by considering the polarization ratio of the NRCS. To demonstrate the applicability of the algorithm, wind fields were computed from several ENVISAT ASAR images of the North Sea and compared to atmospheric model results of the German weather service. %0 conference paper %@ 0379-6566 %A Lehner, S., Horstmann, J., Schulz-Stellenfleth, J., Roth, A., Eineder, M. %D 2004 %J Proceedings of the Second Workshop on Coastal and Marine Applications of SAR %N 565 %P 233-238 %T TerraSAR-X for Oceanography – Mission Overview %U 565 %X The uses of TerraSAR-X system for oceanographic application are discussed. The system has polarimetric and interferometric capabilities as well as very high spatial resolution. These capabilities make it a valuable tool for wind, wave, current measurement, and morphodynamic changes in the oceanography. It is observed that its relatively short revisit time of 11 days also makes TerraSAR-X useful in the monitoring of oil disaster accidents. %0 journal article %@ 0167-6369 %A Hussian, M., Grimvall, A., Petersen, W. %D 2004 %J Environmental Monitoring and Assessment %N 1-3 %P 15-33 %T Estimation of the Human Impact on Nutrient Loads Carried by the Elbe River %U 1-3 %X %0 conference poster %@ 0030-3917 %A Behnert, I., Matthias, V., Doerffer, R. %D 2004 %J AERONET/PHOTONS Workshop 2004 %T Aerosol optical thickness and its spectral dependence derived from sunphotometer measurements over the southern North Sea coastal region %U %X %0 journal article %@ 0323-4320 %A Romanowicz, R., Petersen, W. %D 2004 %J Acta Hydrochimica et Hydrobiologica %N 4-5 %P 319-333 %R doi:10.1002/aheh.200300499 %T Statistical modelling of algae concentrations in the Elbe River in the years 1985-2001 using observations of daily dissolved oxygen, temperature and pH %U https://doi.org/10.1002/aheh.200300499 4-5 %X %0 journal article %@ 1137-2141 %A Orfila, A., Vizoso, G., Alvarez, A., Onken, R. %D 2004 %J Revista de la Real Academia de Ciencias Exactas, Fisicas y Naturales %N 1 %P 191-207 %T La respuesta cientifica ante el vertido del buque Prestige: oceanografia operacional en Enspana y la esperience del IMEDEA %U 1 %X %0 conference lecture (invited) %@ %A Colijn, F., Petschatnikov, M., Schroeder, F., Wehde, H. %D 2004 %J 89. Sitzung der Senatskommission fuer Ozeanographie %T Meeresueberwachung mit der FerryBox - Anwendung und Grenzen %U %X %0 conference paper %@ %A Petersen, W., Petschatnkikov, M., Schroeder, F., Wehde, H. %D 2004 %J Bridges across the oceans, TECHNO-OCEAN 2004 %P 1399-1401 %T Application of a FerryBox: Automatic Measurements in the North Sea %U %X %0 conference lecture %@ %A Petersen, W., Petschatnkikov, M., Schroeder, F., Wehde, H. %D 2004 %J Bridges across the oceans, TECHNO-OCEAN 2004 %T Application of a FerryBox: Automatic Measurements in the North Sea %U %X %0 journal article %@ 0364-9059 %A Alvarez, A., Onken, R., Caiti, A. %D 2004 %J IEEE Journal of Oceanic Engineering %N 2 %P 418-429 %R doi:10.1109/JOE.2004.827837 %T Evolutionary path planning for autonomous underwater vehicles in a variable ocean %U https://doi.org/10.1109/JOE.2004.827837 2 %X This paper proposes a genetic algorithm (GA) for path planning of an autonomous underwater vehicle in an ocean environment characterized by strong currents and enhanced space–time variability. The goal is to find a safe path that takes the vehicle from its starting location to a mission-specified destination, minimizing the energy cost. The GA includes novel genetic operators that ensure the convergence to the global minimum even in cases where the structure (in space and time) of the current field implies the existence of different local minima. The performance of these operators is discussed. The proposed algorithm is suitable for situations in which the vehicle has to operate energy-exhaustive missions. %0 conference lecture %@ %A Colijn, F. %D 2003 %J Treffen zwischen IfK und TNO Physics and Electronics Laboratory (TNO-FEL) %T Aufgaben des Instituts für Küstenforschung, moegliche kuenftige Kooperationen %U %X %0 conference lecture %@ %A Colijn, F. %D 2003 %J Tagung des Umweltausschusses des Staedteverbandes Schleswig-Holstein %T Ueberblick der GKSS-Foeschung zum Thema: Lebensraum Kueste %U %X %0 conference object %@ %A Mahatma, L., Riethmueller, R., Bernem, K.-H.van, Heymann, K. %D 2003 %J Sediment 2003 %T The effect of bedform (Crest and Trough system) on sediment erodibility on a back barrier tidal flat of the East Frisian Wadden Sea %U %X %0 conference paper %@ %A Dankert, H., Horstmann, J., Guenther, H., Rosenthal, W. %D 2003 %J Building the European Capacity in Operational Oceanography, 3rd International Conference on EuroGOOS %P 115-121 %R doi:10.1016/S0422-9894(03)80020-X %T Measurement of wave groups using radar-image sequences %U https://doi.org/10.1016/S0422-9894(03)80020-X %X A method is presented to localise wave groups in space and time utilising radar-image sequences of the ocean surface. The distribution and the properties of individual wave groups in spatial-temporal dimensions are investigated for typical sea states. The wave groups are selected from radar-image sequences, which were acquired by the wave monitoring system WaMoS II, by considering the spatial-temporal wave envelope. The amplitude of the wave envelope is determined by calibrating the image spectrum to an in situ sensor spectrum. It is demonstrated that the method can be employed for the determination of both location and size of wave groups from radar images. The spatial and temporal development of wave groups, their extension and velocities are studied. It is shown that the group velocity of waves measured in shallow and deep water agree on average with the group velocities resulting from linear wave theory, but we will show wave groups on the ocean that move with different velocities. %0 conference lecture %@ %A Ziemer, F., Brockmann, C., Vaughan, R.A., Seemann, J., Senet, C. %D 2003 %J Remote Sensing of the Coastal Zone, 23rd Annual EARSel Symposium %T The OROMA Project %U %X %0 conference lecture (invited) %@ %A Colijn, F. %D 2003 %J Praesentation im BPPT (Technologie-Behoerde) %T FerryBox: An Operational System on Board of Ferryships %U %X %0 journal article %@ 0196-2892 %A Dankert, H., Horstmann, J., Lehner, S., Rosenthal, W. %D 2003 %J IEEE Transactions on Geoscience and Remote Sensing %N 6 %P 1437-1446 %R doi:10.1109/TGRS.2003.811815 %T Detection of wave groups in SAR images and radar image sequences %U https://doi.org/10.1109/TGRS.2003.811815 6 %X The properties of individual wave groups in space and time utilizing synthetic aperture radar (SAR) images and nautical radar image sequences are studied. This is possible by the quantitative measurement and analysis of wave groups both spatially and spatio-temporally. The SAR, with its high spatial resolution and large coverage, offers a unique opportunity to study and derive wave groups. In addition to SAR images, nautical radar image sequences allow the investigation of wave groups in space and time and, therefore, the measurement of parameters such as the group velocity. The detection of wave groups is based on the determination of the envelope function, which was first adopted for one-dimensional (1-D) time series by Longuet-Higgins. The method is extended from 1-D to spatial and spatio-temporal dimensions to derive wave groups in images and image sequences. To test the algorithm, wave groups are derived from SAR images and two radar image sequences, recorded at locations in deep and shallow water. It is demonstrated that the algorithm can be employed for the determination of both location and size of wave groups from radar images. Investigating the detected wave groups in radar image sequences additionally allows the measurement of the spatial and temporal development of wave groups and their extension and phase velocities. Comparison of measured wave group velocities in shallow and deep water gives a deviation of the average value from the group velocities resulting from linear wave theory and shows a clear oscillation of the group velocities in two dimensions.View less %0 conference lecture %@ %A Colijn, F. %D 2003 %J „Mittagsgespraech“ des Husumer CDU-Wirtschaftsrates %T Entwicklung der Meeresforschung und angewandte Meerestechnologien in Schleswig-Holstein %U %X %0 conference lecture (invited) %@ %A Colijn, F. %D 2003 %J Kolloquium zur Verabschiedung von Prof. Dr. J. Suendermann %T Interaktion zwischen Physik und Biologie %U %X %0 conference poster %@ %A Schiller, H., Doerffer, R. %D 2003 %J 3rd Conference on Artificial Intelligence Applications to the Environmental Science %T Combined usage of neural net technology and minimization procedure allows us to improve the retrieval accuracy and to obtain error estimates of concentrations of water constituents from MERIS data %U %X %0 journal article %@ 0906-060X %A Ladwig, N., Hesse, K.-J., Colijn, F., Tillmann, U. %D 2003 %J ICES Marine Science Symposia %P 199-207 %T Has the eutrophic state of German Wadden Sea waters changed over the past 10 years due to nutrient reduction? %U %X %0 journal article %@ 1385-1101 %A Colijn, F., Cadee, G.C. %D 2003 %J Journal of Sea Research %P 83-93 %T Is phytoplankton growth in the Wadden Sea light or nutrogen limited? %U %X %0 journal article %@ 0893-6080 %A Krasnopolsky, V.M., Schiller, H. %D 2003 %J Neural networks %P 321-334 %R doi:10.1016/S0893-6080(03)00027-3 %T Some Neural Network Applications in Environmental Sciences, Part 1: Forward and Inverse Problems in Geophysical Remote Measurements %U https://doi.org/10.1016/S0893-6080(03)00027-3 %X %0 conference lecture %@ %A Colijn, F. %D 2003 %J Feierliche Uebergabe der "Ludwig Prantl" in Kiel %T Welche Forschung braucht das Kuestenmanagement? %U %X %0 conference lecture %@ %A Braun, N., Bezuglov, A., Schymura, G., Ziemer, F. %D 2003 %J International Geoscience and Remote Sensing Symposium %T Sea-surface current measurements with an X band radar %U %X %0 conference lecture %@ %A Riethmueller, R., Mahatma, L., Bernem, K.-H., Heymann, K. %D 2003 %J Intercoh 2003 %T The erodibility of sediment with different benthic macrofauna communities on a tidal flat: Spatial and temporal variation %U %X %0 conference lecture %@ %A Colijn, F. %D 2003 %J Warnsignale aus dem Meer, Symposium im Geomatikum %T Nutzungen im Meer und ihr Konfliktpotential %U %X %0 conference lecture %@ %A Colijn, F. %D 2003 %J Vortragsveranstaltung anlaesslich der Verabschiedung von Prof. Suendermann %T Die Kueste: Wo Oekologie und Physik sich treffen! %U %X %0 conference lecture (invited) %@ %A Colijn, F. %D 2003 %J Eroeffnung des Brantas-Meermaid-Systems %T Vorstellung des Instituts für Kuestenforschung der GKSS %U %X %0 conference lecture (invited) %@ %A Colijn, F., Hesse, K.-J., Kannen, A. %D 2003 %J Workshop Ecological Indicators: Theoretical fundamentals for consistent applications in environmental management %T Eutrophication related indicators for European coastal waters %U %X %0 conference paper %@ %A Petersen, W., Petschatnikov, M., Schroeder, F., Colijn, F. %D 2003 %J Building the European Capacity in Operational Oceanography, 3rd International Conference on EuroGOOS %P 325-333 %T Ferry-Box Systems for Monitoring Coastal Waters %U %X %0 conference paper %@ 0422-9894 %A Pleskachevsky, A., Horstmann, J., Gayer, G., Günther, H., Rosenthal, W. %D 2003 %J Elsevier Oceanography Series %P 122-127 %R doi:10.1016/S0422-9894(03)80021-1 %T Synergy of remote sensing and numerical modelling for monitoring of suspended particulate matter %U https://doi.org/10.1016/S0422-9894(03)80021-1 %X A quasi 3D and fully 3D Suspended Particulate Matter (SPM) Transport model was developed for the North Sea. The model was calibrated utilising the synergy of satellite borne ocean colour data (SPM surface concentrations) and SPM exchange models to determine the vertical exchange coefficients due to currents and waves in the mixing scheme. The vertical exchange model considers erosion, sedimentation and resus- pension, which depend on the local shear velocities and the exchange processes in the seabed. The exchange processes in the seabed take into account bioturbation by benthos as well as diffusion in the bottom layers. This resulted in a quasi 3D and fully 3D SPM model that for the first time are able to reproduce the temporal and spatial evolution of the plume intensity observed in the North Sea. It is shown that the plume calculated with the models agrees very well with the plume visible in a corresponding satellite borne ocean colour imagery. %0 conference paper %@ %A Petersen, W., Romanowicz, R. %D 2003 %J Modellgestuetzte Wasserbewirtschaftung mit hoher zeitlicher Aufloesung, Kolloquium %T Statistische Generierung von Tageswerten der Chlorophyll-Konzentration ausgehend von taeglichen Beobachtungen anderer Variablen %U %X %0 conference paper %@ 0422-9894 %A Lehner, S., Horstmann, J., Hasager, C. %D 2003 %J Elsevier Oceanography Series %P 450-457 %R doi:10.1016/S0422-9894(03)80072-7 %T High-resolution wind fields from synthetic aperture radars and numerical models for offshore wind farming %U https://doi.org/10.1016/S0422-9894(03)80072-7 %X All European countries with shallow coastal waters and strong mean wind speed at the coast have begun planning and construction of offshore wind farms, and large parts of the North Sea and the Baltic are under investigation as to whether they are suitable for offshore parks. This paper demonstrates how satellite images taken by spaceborne radar sensors can be used to determine mesoscale wind fields and thus help in the task of planning offshore wind farms. High resolution SAR (Synthetic Aperture Radar) images acquired by the European remote sensing satellite ERS-2 are presented which show single wind turbines. The derivation of high resolution wind fields from SAR images is explained and comparisons with numerical models are presented. %0 journal article %@ 0196-2892 %A Horstmann, J., Schiller, H., Schulz-Stellenfleth, J., Lehner, S. %D 2003 %J IEEE Transactions on Geoscience and Remote Sensing %N 10 %P 2277-2286 %R doi:10.1109/TGRS.2003.814658 %T Global wind speed retrieval from SAR %U https://doi.org/10.1109/TGRS.2003.814658 10 %X The global availability of synthetic aperture radar (SAR) wave mode data from the European Remote Sensing (ERS) satellites ERS-1 and ERS-2, as well as ENVISAT, allows for the investigation of the wind field over the ocean on a global and continuous basis. For this purpose, 27 days of ERS-2 SAR wave mode data were processed, representing a total of 34310 imagettes of size 10 km /spl times/5 km, available every 200 km along the satellite track. In this paper, two methods for retrieving wind speeds from SAR imagettes are presented and validated, showing the applicability of ENVISAT alike SAR wave mode data for global ocean wind retrieval. The first method is based on the well-tested empirical C-band scatterometer (SCAT) models, which describe the dependency of the normalized radar cross section (NRCS) on wind speed and direction. To apply C-band models to SAR data, the NRCS needs to be accurately calibrated. This is performed by a new efficient method utilizing a subset of colocated measurements from ERS-2 SCAT and model winds from the European Centre for Medium-Range Weather Forecast (ECMWF). SAR wind speeds are computed from the calibrated imagettes and compared to the entire set of colocated ERS-2 SCAT and ECMWF model data. Comparison to ERS-2 SCAT winds result in a correlation of 0.95 with a bias of -0.01 m s/sup -1/ and an rms error of 1.0 m s/sup -1/. The second approach is based on neural networks (NNs), which allow the retrieval of wind speeds from uncalibrated SAR imagettes. NNs are trained using the mean intensity of ERS-2 SAR imagettes and colocated wind data from the ERS-2 SCAT and ECMWF model data. Validation of the NN-retrieved SAR wind speeds to ERS-2 SCAT and ECMWF model wind data result in a correlation of 0.96 with a bias of -0.04 m s/sup -1/ and an rms error of 0.93 m s/sup -1/. %0 conference paper %@ %A Behnert, I., Doerffer, R., Becu, G., Deschamps, P.-Y., Fomferra, N. %D 2003 %J Proceedings of MERIS User Workshop, ESA Publications Division %P CD %T Aerosol retrieval from MERIS and ground-based radiometers for the German Bight, turbid coastal waters %U %X %0 journal article %@ 0021-8502 %A Behnert, I., Doerffer, R., Matthias, V., Kipp, P. %D 2003 %J Journal of Aerosol Science %N S 2 %P 889-890 %T An aerosol climatology over the North Sea for an atmospheric correction of MERIS imagery %U S 2 %X %0 conference poster %@ %A Behnert, I., Doerffer, R., Becu, G., Deschamps, P.-Y., Fomferra, N. %D 2003 %J MERIS User Workshop, ESA ESRIN %T Aerosol retrieval from MERIS and ground-based radiometers for the German Bight, turbid coastal waters %U %X %0 conference lecture %@ %A Horstmann, J., Koch, W. %D 2003 %J 2nd Workshop on Coastal and Marine Applications of SAR %T High Resolution Ocean Surface Wind Fields Retrieved from Spaceborne Synthetic Aperture Radars Operating at C-Band %U %X %0 journal article %@ 0148-0227 %A Onken, R., Brambilla, E. %D 2003 %J Journal of Geophysical Research : Oceans %N C 9 %P 8124 %R doi:10.1029/2002JC001349 %T Double-diffusion in the Mediterranean Sea: Observation and paramerization of salt finger convection %U https://doi.org/10.1029/2002JC001349 C 9 %X For the Mediterranean Sea a large set of historical conductivity-temperature-depth casts has been investigated for the occurrence of double-diffusive vertical mixing due to salt finger convection. All casts were screened in terms of the density ratio Rρ, providing probability distributions of Rρ for the upper 1000-dbar range of eight geographical areas. Vertical profiles of the salt finger-driven diffusivities kS and kT of salinity and temperature have been evaluated from the statistics of Rρ and a presumed mixing law, and analytic expressions are provided, which can be used to parameterize the effects of salt finger mixing in ocean circulation models of the Mediterranean. In most areas the diffusivity profiles exhibit an absolute maximum below the core of the Levantine Intermediate Water. Toward the surface the diffusivities decrease rapidly, while the downward decay is less pronounced. A different behavior is found in the Tyrrhenian and Adriatic Seas, where the diffusivities remain high also at greater depth. %0 journal article %@ 0148-0227 %A Onken, R., Robinson, A.R., Lermusiaux, P.F.J., Haley, P.J.Jr., Anderson, L.A. %D 2003 %J Journal of Geophysical Research : Oceans %N C 9 %P 8123 %R doi:10.1029/2002JC001348 %T Data-driven Simulations of Synoptic Circulation and Transports in the Tunisia-Sardinia-Sicily region %U https://doi.org/10.1029/2002JC001348 C 9 %X Data from a hydrographic survey of the Tunisia-Sardinia-Sicily region are assimilated into a primitive equations ocean model. The model simulation is then averaged in time over the short duration of the data survey. The corresponding results, consistent with data and dynamics, are providing new insight into the circulation of Modified Atlantic Water (MAW) and Levantine Intermediate Water (LIW) in this region of the western Mediterranean. For MAW these insights include a southward jet off the east coast of Sardinia, anticyclonic recirculation cells on the Algerian and Tunisian shelves, and a secondary flow splitting in the Strait of Sicily. For the LIW regime a detailed view of the circulation in the Strait of Sicily is given, indicating that LIW proceeds from the strait to the Tyrrhenian Sea. No evidence is found for a direct current path to the Sardinia Channel. Complex circulation patterns are validated by two-way nesting of critical regions. Volume transports are computed for the Strait of Sicily, the Sardinia Channel, and the passage between Sardinia and Sicily. %0 conference paper %@ %A Schiller, H. %D 2003 %J CIMSA 2003, International Symposium for Computational Intelligence and Applications %P 79-84 %T Neural Net Architectures for Scope Check and Monitoring %U %X %0 journal article %@ 0303-2434 %A Thiemann, S., Schiller, H. %D 2003 %J International Journal of Applied Earth Observation and Geoinformation %P 339-349 %T Determination of the bulk temperature from NOAA/AVHRR satellite data in a midlatitude lake %U %X %0 GKSS report %@ %A Cysewski, M.-C. %D 2003 %J %T Radarscanning in der Hydrographie (Diplomarbeit) %U %X %0 conference paper %@ %A Dankert, H., Horstmann, J., Rosenthal, W. %D 2002 %J Proceedings of the 21st International Conference on Offshore Mechanics and Arctic Engineering (OMAE) %P 165-172 %T Detection of Extreme Waves in SAR Images and Radar-Image Sequences %U %X Extreme waves are often enclosed by other waves which are also higher than the average. These wave groups have to be taken into account for instance for the design of offshore platforms, breakwaters or ships, because successive high waves can cause more damage on those structures than the same waves separated by smaller waves. Further they can excite the resonance frequencies of moored structures like platforms due to non-linear effects or cause capsize. They are therefore of interest for engineers and scientists (e.g. Goda 1983). A method is presented to localize wave groups spatial and spatio-temporal utilizing synthetic aperture radar (SAR) images and nautical radar-image sequences. The approach to detect wave groups is based on the detection of the wave envelope. It is assumed that the sea surface elevation can be treated as a Gaussian process. The method is applied to SAR images acquired by the European satellite ERS-1 and to radar-image sequences recorded by tower-based nautical radars. In contrast to 1D sensors like buoys the SAR records an image and gives therefore a 2D description of the sea surface by measuring the radar backscatter from the sea surface. The measurements taken by a nautical radar provide the possibility to record time series of images and therefore to get a 3D description of the sea surface. Radar-image sequences are acquired by recording the spatial and temporal evolution of the sea surface backscatter, which is modulated through the surface wave field. Nautical radar-image sequences allow to detect wave groups within a time span that makes it possible to start safety programs before the group reaches a platform. The existing data sets are exploited with respect to the recognition of extreme wave events. %0 conference lecture %@ %A Horstmann, J., Schaettler, B., Lehner, S. %D 2002 %J International Geoscience and Remote Sensing Symposium, IGARSS 2002 %T A new method for radiometric calibration of SAR and its global monitoring %U %X %0 conference lecture (invited) %@ %A Horstmann, J., Koch, W., Lehner, S. %D 2002 %J EUMETSAT 2002, Meteorological Satellite Conference %T High resolution SAR derived wind fields in comparison to numerical models %U %X %0 conference lecture %@ %A Pleskaschevski, A., Horstmann, J., Gayer, G., Guenther, H., Rosenthal, W. %D 2002 %J 3rd EuroGOOSE Conference %T Synergy of Remote Sensing and Numerical Modelling for Monitoring of Suspended Particulate Matter %U %X %0 GKSS report %@ %A Horstmann, J. %D 2002 %J %T Measurements of Ocean Wind Fields with Synthetic Aperture Radar (Dissertation) %U %X %0 conference lecture %@ %A Horstmann, J., Koch, W., Lehner, S. %D 2002 %J 6th International Winds Workshop %T Wind fields retrieved from SAR in comparison to numerical models %U %X %0 conference lecture %@ %A Horstmann, J., Koch, W., Lehner, S., Tonboe, R. %D 2002 %J 21st International Conference on OMAE %T High Resolution Wind Fields Retrieved from Spaceborne Synthetic Aperture Radar Images in Comparison to Numerical Models %U %X %0 conference lecture %@ %A Horstmann, J., Koch, W., Lehner, S. %D 2002 %J International Geoscience and Remote Sensing Symposium, IGARSS 2002 %T Global Wind fields from SAR data using Scatterometer Models and Neural Networks %U %X %0 conference lecture %@ %A Petersen, W., Romanowicz, R. %D 2002 %J Modellgestuetzte Wasserbewirtschaftung mit hoher zeitlicher Aufloesung, Kolloquium %T Statistische Generierung von Tageswerten der Chlorophyll-Konzentration ausgehend von taeglichen Beobachtungen anderer Variablen %U %X %0 conference lecture %@ %A Pleskaschevski, A., Horstmann, J., Gayer, G., Rosenthal, W. %D 2002 %J IGARSS 2002, Internatioanl Geoscience and Remote Sensing Symposium %T Synergy of Remote Sensing and Numerical Modeling for Suspended Matter Transport %U %X %0 conference lecture (invited) %@ %A Horstmann, J., Koch, W., Lehner, S. %D 2002 %J International Geoscience and Remote Sensing Symposium, IGARSS 2002 %T High resolution wind fields retrieved from SAR in comparison to numerical models %U %X %0 conference lecture %@ %A Dankert, H., Horstmann, J., Guenther, H., Rosenthal, W. %D 2002 %J 3rd International Conference on EuroGOOS %T Measurement of Wave Groups using Radar-Image Sequences %U %X %0 journal article %@ 0703-8992 %A Horstmann, J., Koch, W., Lehner, S., Tonboe, R. %D 2002 %J Canadian Journal of Remote Sensing %N 3 %P 524-533 %T Ocean winds from RADARSAT-1 ScanSAR %U 3 %X %0 journal article %@ 0323-4320 %A Petersen, W., Callies, U. %D 2002 %J Acta Hydrochimica et Hydrobiologica %N 1 %P 34-40 %T Assessment of Primary Production by Statistical Analysis of Water-quality Data %U 1 %X %0 conference lecture %@ %A Horstmann, J., Koch, W., Lehner, S., Tonboe, R. %D 2002 %J Oceanology International 2002 %T High resolution wind fields retrieved from spaceborn synthetic aperture radar images in comparison to numerical models %U %X %0 conference lecture %@ %A Lehner, S., Horstmann, J., Hasager, C. %D 2002 %J 3rd EuroGOOS Conference %T High-resolution wind fields from synthetic aperture radars and numerical models for offshore wind farming %U %X %0 conference lecture %@ %A Horstmann, J., Koch, W., Lehner, S. %D 2002 %J 11th International Biennial Conference on Physics of Estuaries and Coastal Seas %T Coastal wind fields retrieved from spaceborne synthetic aperture radar images in comparison to numerical models %U %X %0 interview %@ %A Colijn, F. %D 2002 %J WNO: Wirtschaftsmagazin der Industrie- und Handelskammern zu Kiel und zu Flensburg %N 7 %P 11 %T Interview: Es sind neue Maerkte zu erobern %U 7 %X %0 conference poster %@ %A Colijn, F., Petersen, W. %D 2002 %J 3rd EuroGOOS Conference %T European Ferrybox Project: From Online Oceanographic Measurements to Environmental Information %U %X %0 conference lecture %@ %A Petersen, W., Petschatnikov, M., Schroeder, F., Colijn, F. %D 2002 %J Building the European Capacity in Operational Oceanography, 3rd International Conference on EuroGOOS %T Ferry-Box Systems for Monitoring Coastal Waters %U %X %0 conference paper %@ %A Horstmann, J., Weinreich, I., Hauser, D., Lehner, S., Koch, W. %D 2002 %J Operational oceanography, Implementation at the European and Regional Scales, International Conference on EuroGOOS %P 445-453 %R doi:10.1016/S0422-9894(02)80051-4 %T SAR Wind Measurements during the FETCH Experiment %U https://doi.org/10.1016/S0422-9894(02)80051-4 %X %0 journal article %@ 0018-8158 %A Colijn, F., Hesse, K.-J., Ladwig, N., Tillmann, U. %D 2002 %J Hydrobiologia %P 133-148 %T Effects of the large-scale uncontrolled fertilisation process along the continental coastal North Sea %U %X %0 conference paper %@ %A Lehner, S., Schulz-Stellenfleth, J., Niedermeyer, A., Horstmann, J., Rosenthal, W. %D 2002 %J Proceedings of the 21st International Conference on Offshore Mechanics and Arctic Engineering, OMAE 2002 %P 251-256 %R doi:10.1115/OMAE2002-28293 %T Extreme waves detected by satellite borne synthetic aperture radar %U https://doi.org/10.1115/OMAE2002-28293 %X Within the last 20 years at least 200 supercarriers have been lost, due to severe weather conditions. In many cases the cause of accidents is believed to be 'Rouge waves', which are individual waves of exceptional wave height or abnormal shape. I situ measurements of extreme waves are scarce and most observations are reported by ship masters after the encounter. In this paper a global set of synthetic aperture radar (SAR) images is used to detect extreme ocean wave events. The data were acquired aboard the European remote sensing satellite ERS-2 every 200 km along the track. As the data are not available as a standard product of the Europea Space Agency (ESA), the radar raw data were focused to complex SAR images using the processor BSAR developed by the German Aerospace Center. The entire SAR data set covers 27 days representing 34000 SAR imagettes with a size of 5 km × 10 km. Complex SAR data contain information on ocean wave height, propagation direction and grouping as well as on ocean surface winds. Combining all of this information allows to extract and locate extreme waves from complex SAR images on a global basis. Special algorithms have been developed to retrieve the following parameters from the SAR data: Wind speed and direction, significant wave height, wave direction, wave groups and their individual heights. The satellite ENVISAT launched in March 2002 acquires SAR data with an even higher sampling rate (every 100 km). It is expected that a long-term analysis of ERS and ENVISAT data will give new insight into the physical processes responsible for rogue wave generation. Furthermore, the identification of hot spots will contribute to the optimization of ship routes. %0 conference lecture (invited) %@ %A Colijn, F. %D 2002 %J Tagung "Forschungshorizonte der Kuestenregion" %T Die Kueste als Lebensraum: Forschungsaufgaben zur nachhaltigen Nutzung %U %X %0 conference lecture %@ %A Colijn, F. %D 2002 %J Vortrag an der Universitaet Danzig %T Use of ships-of-opportunity for monitoring and eutrophication of the Wadden Sea %U %X %0 journal article %@ %A Colijn, F., Petersen, W. %D 2002 %J ICES CIEM newsletter %N 6 %P 3-5 %T Collecting Oceanography Data from Ferries %U 6 %X %0 conference poster %@ %A Doerffer, R., Schiller, H. %D 2002 %J Ocean Optics XVI %T First Results of the Retrieval of Concentrations of Water Constituents from MERIS Data: Concentration and Related Error Maps %U %X %0 conference lecture (invited) %@ %A Colijn, F. %D 2002 %J Geophysikalisches Kolloquium im SS 2002 der Universitaet Hamburg, Meteorologisches Institut %T Operationelle Messsysteme und Monitoring der Kuestenmeere %U %X %0 conference lecture %@ %A Colijn, F., Petersen, W., Petschatnikov, M., Schroeder, F. %D 2002 %J ICES Annual Science Conference %T A New System for Automatic Measurements of Biological-Chemical Parameters from Ferry Boats %U %X %0 conference poster %@ %A Doerffer, R., Schiller, H. %D 2002 %J Ocean Optics XVI %T A Neural Network Based Atmospheric Correction Procedure for the Retrieval of Water Constituent Concentrations in Turbid Case II Water from MERIS Data %U %X %0 conference lecture (invited) %@ %A Colijn, F. %D 2002 %J Summerschool, Institut fuer Ostseeforschung %T Background and Direction of Monitoring %U %X %0 conference lecture %@ %A Ziemer, F., Seemann, J., Senet, C. %D 2001 %J The Fourth International Symposium on Ocean Wave Measurement and Analysis %T Observing wave propagation in coastal areas %U %X %0 conference lecture %@ %A Lehner, S., Schulz-Stellenfleth, J., Koenig, T., Horstmann, J., Bao, M. %D 2001 %J International Geoscience and Remote Sensing Symposium, IGARSS 2001 %T Global distribution of sea surface features from SAR Wave Mode data %U %X %0 conference lecture %@ %A Lehner, S., Guenther, H., Horstmann, J., Bao, M., Schulz-Stellenfleth, J. %D 2001 %J International Geoscience and Remote Sensing Symposium, IGARSS 2001 %T Joint Along-Across Track Interferometry of Ocean Waves %U %X %0 conference lecture %@ %A Horstmann, J., Lehner, S., Schiller, H. %D 2001 %J International Geoscience and Remote Sensing Symposium, IGARSS 2001 %T Global Wind Speed Retrieval from Complex SAR data using Scatterometer Models and Neural Networks %U %X %0 conference lecture %@ %A Horstmann, J., Koch, W., Lehner, S., Tonboe, R. %D 2001 %J IGARSS 2001 International Geoscience and Remote Sensing Symposium %T Coastal high resolution wind fields retrieved from RADARSAT-1 ScanSAR %U %X %0 conference lecture %@ %A Lehner, S., Horstmann, J., Schulz-Stellenfleth, J., Bao, M., Koch, W. %D 2001 %J 11th Conference on Interactions of the Sea and Atmosphere %T Global Measurements of Wind using Complex Synthetic Aperture Radar Images %U %X %0 journal article %@ 0196-2892 %A Schulz-Stellenfleth, J., Horstmann, J., Lehner, S., Rosenthal, W. %D 2001 %J IEEE Transactions on Geoscience and Remote Sensing %N 9 %P 2017-2028 %T Sea Surface Imaging With an Across-Track Interferometric Synthetic Aperture Radar: The SINEWAVE Experiment %U 9 %X %0 conference lecture %@ %A Senet, C.M., Seemann, J., Ziemer, F. %D 2001 %J Capture, Analysis and Display of Image Sequences III, SPIE - The International Society of Optical Engineering %T Classification of Dynamic Surfaces: a Proposal to Transfer a Method Which Determines Hydrographic-Parameter Maps from Image Sequences of the Ocean-Sea Surface to Solid-Matter Physics %U %X %0 conference lecture %@ %A Horstmann, J., Koch, W., Lehner, S., Tonboe, R. %D 2001 %J European Geophysical Society, 26.General Assembly %T Mesoscale Wind Field Retrieval using Space Borne Synthetic Aperture Radar %U %X %0 conference lecture %@ %A Horstmann, J., Koch, W., Lehner, S., Tonboe, R. %D 2001 %J 11th Conference on Interactions of the Sea and Atmosphere %T An Algorithm for Operational Wind Field Retrieval Using RADARSAT-1 ScanSAR Images %U %X %0 conference lecture %@ %A Schulz-Stellenfleth, J., Lehner, S., Horstmann, J., Hoja, D., Bao, M. %D 2001 %J CEOS WGCV-SAR Workshop ( Working Group on Calibration and Validation) %T Global Wind and Ocean Wave Measurements with the ENVISAT ASAR Wave Mode %U %X %0 conference paper %@ %A Schiller, H., Krasnopolsky, V. %D 2001 %J INNS - IEEE International Joint Conference on Neural Networks %P 2150-2152 %T Domain Check for Input to NN Emulating an Inverse Model %U %X %0 conference lecture %@ %A Horstmann, J., Koch, W., Lehner, S., Tonboe, R., Bamler, R. %D 2001 %J CEOS WGCV-SAR Workshop 2001 ( Working Group for Calibration and Validation) %T High resolution wind fields retrieved from RADARSAT-1 ScanSAR %U %X %0 online contribution %@ %A Horstmann, J., Koch, W. %D 2001 %J Volvo Ocean Adventure %T Wind from satellite borne synthetic aperture radars %U %X %0 report %@ %A Lehner, S., Winkel, N., Hoja, D., Horstmann, J., Niedermeier, A., Romaneessen, E., Rudolph, E., Schulz-Stellenfleth, J., Siegmund, R. %D 2001 %J %T Synergie von Fernerkundung und mathematischen Tidemodellen zur Optimierung divergierender Nutzungsansprueche in Aestuaren %U %X %0 GKSS report %@ %A Schiller, K. %D 2001 %J %T Derivation of the Photosynthetically Available Radiation from METEOSAT Data %U %X %0 conference paper %@ %A Doerffer, R., Schiller, H. %D 2001 %J 4th Berlin Workshop on Ocean Remote Sensing: '5 Years of MOS-IRS' %P 89-96 %T An optical component model for training of a neural network case 2 water algorithm %U %X %0 conference lecture (invited) %@ %A Colijn, F. %D 2001 %J Structuring Factors of Shallow Marine Coastal Communities %T Is growth of Wadden Sea phytoplankton light or nutrient limited? %U %X %0 book part %@ %A Ahlf, W., Flemming, H., Götz, R., Hupfer, M., Leuchs, H., Lorch, D., Petersen, W., Remde, A., Traunspurger, W. %D 2001 %J Untersuchung und Bewertung von Sedimenten : Ökotoxikologische und chemische Testmethoden %P 7-65 %R doi:10.1007/978-3-642-56483-3_2 %T Sedimente als Lebensraum %U https://doi.org/10.1007/978-3-642-56483-3_2 %X Sedimente bilden Habitate für zahlreiche Organismen und Biozönosen, die in oder auf dem Sediment leben und allgemein als Benthos bezeichnet werden. Neben dem Benthos, dessen tierischer Anteil sich aus der Endofauna (oder Infauna) und Epifauna zusammensetzt, sind Sedimente Lebensraum für bakterielle, pflanzliche und tierische Mikroorganismen. Der Groβteil der Organismen besiedelt die oberen Zentimeter des Sediments, während die tieferen Schichten nur von wenigen Spezialisten bewohnt wird. Diese Stratifikation der Sedimente ist weitgehend Resultat mikrobieller Aktivitäten wie Sauerstoffverbrauch beim Abbau von organischen Stoffen, Denitrifikation oder Schwefelwasserstoffproduktion durch bakterielle Sulfatreduktion. Bakterien kommen auf Grund ihrer geringen Gröβe, ihren vielfältigen Ernährungsmöglichkeiten und Stoffwechselaktivitäten nahezu ubiquitär vor. Ein mariner Sedimentausschnitt mit der Fläche von 1 cm2 bis zu einer Sedimenttiefe von 10 cm weist etwa 4×1010 Bakterienzellen auf (Fenchel, 1992). Die gleiche Zahl wird für Süβwassersedimente pro ml angegeben (Schallenberg & Kalff, 1993). Eigene Untersuchungen am oligotrophen Brunnsee (Bayern) ergaben selbst im Profundal (16 mWassertiefe) eine mittlere Bakteriendichte von 109-1010 Bakterienzellen pro ml (Bergtold & Traunspurger, in Vorbereitung). Bakterien spielen eine bedeutende Rolle im Sediment bei allen wichtigen Stoffkreisläufen, Wichtige mikrobielle Prozesse sowie ihre zeitliche und räumliche Varianz sind z.B. bei (1992) für einen winzigen Bruchteil eines Sediments beschrieben (vgl. auch Review: Bonner et al., 1990). %0 journal article %@ 0304-3800 %A Petersen, W., Bertino, L., Callies, U., Zorita, E. %D 2001 %J Ecological Modelling %N 1 - 3 %P 193-213 %T Process identification by principal component analysis of river water-quality data %U 1 - 3 %X %0 conference poster %@ %A Senet, C.M., Seemann, J., Ziemer, F. %D 2001 %J International Workshop on Physical Modelling of Flow and Dispersion Phenomena %T Classification of Dynamic Dispersive Surfaces: A Proposal to Transfer a Method Which Determines Hydrographic-Parameter Maps from Images Sequences of the Ocean-Sea Surface to Solid-Matter Physics %U %X %0 journal article %@ 0196-2892 %A Senet, C.M., Seemann, J., Ziemer, F. %D 2001 %J IEEE Transactions on Geoscience and Remote Sensing %N 3 %P 492-505 %T The Near-Surface Current Velocity Determined from Image Sequences of the Sea Surface %U 3 %X %0 conference lecture %@ %A Schiller, H., Krasnopolsky, V. %D 2001 %J INNS - IEEE International Joint Conference on Neural Networks %T Domain Check for Input to NN Emulating an Inverse Model %U %X %0 conference lecture %@ %A Doerffer, R., Schiller, H. %D 2001 %J 4th Berlin Workshop on Ocean Remote Sensing: '5 Years of MOS-IRS' %T An optical component model for training of a neural network case 2 water algorithm %U %X %0 conference lecture (invited) %@ %A Pleskachevsky, A., Horstmann, J., Rosenthal, W. %D 2001 %J 4th Berlin Workshop on Ocean Remote Sensing %T Modeling of Sediment Transport in Synergy with Ocean Colour Data %U %X %0 conference poster %@ %A Petersen, W., Callies, U. %D 2001 %J Jahrestagung der Wasserchemischen Gesellschaft der GDCh %T Assessment of Primary Production by Statistical Analysis of Water-Quality Data %U %X %0 conference lecture %@ %A Lehner, S., Horstmann, J., Hasager, C. %D 2001 %J Offshore Wind Energy, EWEA Special topic Conference %T High resolution wind fields retrieved from spaceborne synthetic aperture radar images and numerical models %U %X %0 journal article %@ 1231-3726 %A Lehner, S., Schulz-Stellenfleth, J., Horstmann, J. %D 2001 %J Archives of Hydro-Engineering and Environmental Mechanics %N 14 %P 3-15 %T Marine Parameters from Radar Satellite Data %U 14 %X %0 conference lecture (invited) %@ %A Lehner, S., Schulz-Stellenfleth, J., Hoja, D., Horstmann, J. %D 2000 %J Ocean Winds %T Test of ENVISAT ASAR wind measurement techniques using complex ERS-2 wave mode data %U %X %0 conference paper %@ %A Wolff, U., Kruger, A., Senet, C.M., Seemann, J., Ziemer, F. %D 2000 %J IGARSS 2000, IEEE 2000, International Geoscience and Remote Sensing Symposium %P 2420-2422 %R doi:10.1109/IGARSS.2000.859595 %T Optimization of Coastal High-Accuracy Bathymetry Monitoring Campaigns by the Analysis of Continual Radar Observations %U https://doi.org/10.1109/IGARSS.2000.859595 %X Morphodynamical processes in coastal waters are induced by sea state and currents. Vice versa the hydrodynamic regime is influenced by the actual bathymetry. Spatio-temporal changes in the bathymetry can be detected by the analysis of continually acquired radar image sequences showing the roughness of the sea surface. The analysis of the image sequences is performed using a wavelet edge detection algorithm. Ship campaigns for coastal bathymetry monitoring, e.g. with multibeam echo sounders are time consuming and expensive. Therefore a strategy is proposed to use the a priori information on the spatio-temporal bathymetry variations retrieved from the radar image sequences as a warning indicator. This indicator can be utilized to optimize the performance of high-accuracy ship measurement campaigns, focusing on the detection and observation of those regions which show high morphodynamical activity. The presented concept is of interest in order to monitor harbour entrances, estuaries, or endangered coastal sectors. %0 conference paper %@ %A Senet, C.M., Seemann, J., Ziemer, F. %D 2000 %J IGARSS 2000, International Geoscience and Remote Sensing Symposium %P 843-846 %R doi:10.1109/IGARSS.2000.861722 %T Hydrographic Parameter Maps Deduced From CCD Image Sequences of the Water Surface Supplemented by In-Situ Wave Gauges %U https://doi.org/10.1109/IGARSS.2000.861722 %X A new technique, which utilizes a combination of image sequences acquired by CCD cameras and in-situ data sets, is used to observe and analyze inhomogeneous spatiotemporal wave fields in hydraulic wave tanks. The analysis technique allows the determination of hydrographic parameters, like the near-surface current velocity vector, the water depth, and full directional calibrated wave spectra. After a geometric transformation of the image sequence from image coordinates to world coordinates the sequence is transformed to the three-dimensional wavenumber-frequency spectrum. Spectral filtering techniques allow a directional-frequency separation for each single wave of the sea-state signal. By an inverse transformation to the spatial domain noise-reduced phase and power maps of single waves are retrieved. The wavenumbers of these waves are determined by a fitting algorithm on a high-resoluted spatial scale. The composition of waves from all directions and frequencies results in a local wavenumber image spectrum. In-situ wave gauges at single points in the imaged area are used to calibrate the image spectra. This method is useful for impact studies on marine structures or beach studies in wave facilities. The analysis methods have been tested for optical sensors and as well for nautical X-band radar image sequences. This gives oceanographers, offshore, and coastal engineers a tool to study the spatio-temporal behaviour of complex wave fields in hydraulic wave tanks and in nature. %0 conference paper %@ %A Senet, C.M., Seemann, J., Hatten, H., Horstmann, J., Ziemer, F. %D 2000 %J IGARSS 2000, International Geoscience and Remote Sensing Symposium %P 2086-2089 %R doi:10.1109/IGARSS.2000.858281 %T The Future Role of Image Sequence Analysis in Oceanography %U https://doi.org/10.1109/IGARSS.2000.858281 %X The sea surface is a spatio-temporal phenomenon. The acquisition and analysis of image sequences of the sea surface therefore allows a complete representation of the sea state. In nature ship- or land-based nautical radar is used to acquire image sequences. In simulations, i.e., hydraulic wave tanks, optical sensors are used for this purpose. From the image sequences it is possible to determine a set of hydrographic parameters such as wave spectra, current-vector fields, and bathymetry. Examples of applications are presented to show the potential of the methods to monitor coastal or offshore wave fields in the context of an integrated approach. %0 conference lecture %@ %A Senet, C.M., Seemann, J., Hatten, H., Ziemer, F. %D 2000 %J IGARSS 2000, IEEE 2000 International Geoscience and Remote Sensing Symposium, Taking the Pulse of the Planet: The Role of Remote Sensing in Managing the Global Environment %T The Future Role of Image Sequence Analysis in Oceanography %U %X %0 conference paper %@ %A Hatten, H., Seemann, J., Senet, C.M., Bezuglov, A., Veremjev, V., Ziemer, F. %D 2000 %J IGARSS 2000, International Geoscience and Remote Sensing Symposium %P 899-901 %R doi:10.1109/IGARSS.2000.861738 %T Determination of the Near Surface Current Field from Doppler Shift of the Coherent Radar Backscatter Under Grazing Incidence %U https://doi.org/10.1109/IGARSS.2000.861738 %X The aim of this work is to develop a radar remote sensing system for the retrieval of a current map with a spatial coverage of around 1/spl times/1 square kilometers and the resolution of a conventional radar. In co-operation with the Electro-Technical University of St. Petersburg a nautical radar, which normally detects only the amplitudes of the backscatter, is upgraded by a second, 90 degree phase shifted output- channel, to get a coherent signal. With a coherent system the surface current can be detected by the Doppler frequency shift of the backscattered signal. In comparision to a full coherent radar the advantage is clearly the very low price. In this presentation Doppler spectra taken in the Finish Gulf in October'98 during the first test phase of the new system are shown and the problems due to the influence of the wind speed and surface waves are discussed. %0 conference paper %@ %A Horstmann, J., Koch, W., Lehner, S., Tonboe, R. %D 2000 %J Oceans 2000 %P 1321-1327 %T Mapping of Mesoscale wind Fields Using RADARSAT-1 ScanSAR Images %U %X %0 conference paper %@ %A Schulz-Stellenfleth, J., Lehner, S., Horstmann, J. %D 2000 %J IGARSS 2000, International Geoscience and Remote Sensing Symposium %P 272-274 %R doi:10.1109/IGARSS.2000.860489 %T Using ERS-2 Wave Mode Cross Spectra to simulate ENVISAT ASAR Ocean Wave Retrieval %U https://doi.org/10.1109/IGARSS.2000.860489 %X A global dataset of complex synthetic aperture radar (SAR) images processed from wave mode raw data acquired by the European remote sensing satellite ERS-2 is used to measure ocean waves. Cross spectra of two looks extracted from the azimuth spectrum of wave mode imagettes are used to derive ocean wave propagation directions on a global basis. Energy and propagation direction derived from wave mode cross spectra are compared with ocean wave model data from the European center for medium range weather forecasts (ECMWF). A new inversion scheme for the retrieval of two dimensional wave spectra from SAR cross spectra is presented. The algorithm is based on a maximum a posteriori estimation which combines the information from SAR measurements with a priori knowledge on short ocean waves. A new regularization approach is used to impose smoothness constraints on the retrieved wave spectra. %0 conference paper %@ %A Bernem, K.-H.van, Bluehm, B., Krasemann, H. %D 2000 %J Oil and Hydrocarbon Spills, Modelling, Analysis and Control 2 %P 229-238 %T Sensitivity mapping of particular vulnerable sensitive areas %U %X %0 conference lecture (invited) %@ %A Tonboe, R., Gill, R., Horstmann, J. %D 2000 %J Ocean Winds %T Sea surface winds using Radarsat ScanSAR in the Greenland Ice Service %U %X %0 conference lecture (invited) %@ %A Horstmann, J., Koch, W., Lehner, S., Rosenthal, W. %D 2000 %J Ocean Winds %T High resolution wind fields and their variation extracted from ERS-SAR images %U %X %0 conference lecture (invited) %@ %A Horstmann, J., Koch, W., Lehner, S., Tonboe, R. %D 2000 %J Ocean Winds %T Mesoscale Wind Fields Extracted from C-band HH-polarized RADARSET -1 ScanSAR Images %U %X %0 conference lecture %@ %A Romaneessen, E., Lehner, S., Niedermeier, A., Horstmann, J. %D 2000 %J 6th International Conference on Remote Sensing for Marine and Coastal Environment %T Morphodynamic in the Elbe Estuary as Seen by ERS Synthetic Aperture Radar %U %X %0 GKSS report %@ 0278-4343 %A Riethmueller, R., Heineke, M., Kuehl, H., Keuker-Ruediger, R. %D 2000 %J Continental Shelf Research %N 10-11 %P 1351-1372 %T Chlorophyll Alpha concentration as an index of sediment surface stabilisation by microphytobenthos ? %U 10-11 %X %0 conference paper %@ %A Horstmann, J., Koch, W., Lehner, S., Romaneessen, E., Tonboe, R. %D 2000 %J Proceedings of the Sixth International Conference on Remote Sensing for Marine and Coastal Environment %P 457-464 %T Extraction of Ocean Wind Fields using RADARSAT-1 ScanSAR Images %U %X %0 conference lecture %@ %A Lehner, S., Schulz-Stellenfleth, J., Schaettler, B., Horstmann, J. %D 2000 %J EUSAR 2000 - 3rd European Conference on Synthetic Aperture Radar %P 711 %T Global Measurements of Wind Using Complex Synthetic Aperture Radar Images %U %X %0 conference lecture %@ %A Seemann, J., Senet, C.M., Hatten, H., Wolff, U. %D 2000 %J EGS 2000, European Geophysical Society, XXV General Assembly %T High Resolution Wave and Current Measurements Using a Nautical Radar %U %X %0 conference lecture %@ %A Hatten, H., Seemann, J., Bezuglov, A., Veremjev, V., Ziemer, F. %D 2000 %J EGS 2000, European Geophysical Society, XXV General Assembly %T Determination of the near surface current field out of the Doppler shift of the coherent radar backscatter %U %X %0 conference lecture %@ %A Tanaka, A., Kishino, M., Oishi, T., Doerffer, R., Schiller, H. %D 2000 %J Remote sensing of the Ocean and Sea Ice 2000 %P 144-152 %T Application of neural network method to case II water %U %X %0 conference lecture %@ %A Senet, C.M., Seemann, J., Hatten, H., Ziemer, F. %D 2000 %J EGS 2000, European Geophysical Society, XXV General Assembly %T The relevancy of image sequence analysis in oceanography %U %X %0 conference lecture (invited) %@ %A Lehner, S., Schulz-Stellenfleth, J., Horstmann, J. %D 2000 %J ERS-ENVISAT Symposium %T Global Observations of Wind Speed and Sea Surface Features using SAR Wave Mode %U %X %0 GKSS report %@ %A Petersen, W., Bertino, L., Callies, U., Zorita, E. %D 2000 %J %T Process identification by statistical analysis of water-quality data %U %X %0 conference object %@ %A Horstmann, J., Koch, W., Lehner, S., Tonboe, R. %D 2000 %J Proceedings of EuSAR 2000, 3rd European Conference on Synthetic Aperture Radar %P 327 %T Wind Speed Retrieval from RADARSAT-1 ScanSAR %U %X %0 conference lecture %@ %A Kishino, M., Tanaka, A., Oishi, T., Doerffer, R., Schiller, H. %D 2000 %J Hyperspectral Remote Sensing of the Ocean, Proceedings of SPIE %P 179-187 %T Temporal and Spatial Variability of Chlorophyll a, Suspended Solids and Yellow substance in the Yellow Sea and East China Sea Using Ocean Color Sensor %U %X %0 conference object %@ %A Doerffer, R. %D 2000 %J Bio-ecological Observations in Operational Oceanography %P 12 %T Remote Sensing of Primary Production Variables in Coastal Waters %U %X %0 conference lecture %@ %A Petersen, W., Callies, U. %D 2000 %J Gewaesser, Landschaften - 9. Magdeburger Gewaesserschutzseminar %P 49-52 %T Bewertung von Veraenderungen in der Gewaesserqualitaet der Elbe durch statistische Auswertung von Gewaesserdaten %U %X %0 GKSS report %@ %A Schiller, H. %D 2000 %J %T Feedforward-Backpropagation Neural Net Program ffbp1.0 %U %X %0 conference lecture (invited) %@ %A Horstmann, J., Koch, W., Lehner, S., Tonboe, R. %D 2000 %J Oceans from Space %T Mapping of mesoscale ocean wind fields using RADARSAT-1 ScanSAR %U %X %0 conference lecture %@ %A Stuhlmann, R., Macke, A., Doerffer, R., Dammann, K. %D 2000 %J ESA, EUMETSAT Workshop on MSG-RAO, ESA SP-452 %T Aerosol/Cloud Effects: Implication on the Radiation Budget and Atmospheric Correction %U %X %0 conference lecture %@ %A Doerffer, R., Schiller, H. %D 2000 %J IEEE 2000 International Geoscience and Remote Sensing Symposium %P 714-717 %T Neural Network for Retrieval of Concentrations of Water Constituents with the Possibility of Detecting Exceptional out of Scope Spectra %U %X %0 conference lecture (invited) %@ %A Schulz-Stellenfleth, J., Lehner, S., Horstmann, J. %D 2000 %J ERS - ENVISAT Symposium %T SAR Ocean Wave Inversion - A Hierarchic Approach %U %X %0 conference paper %@ %A Senet, C.M., Seemann, J., Ziemer, J. %D 2000 %J Oceans 2000 %P 1769-1774 %R doi:10.1109/OCEANS.2000.882196 %T Dispersive surface classification: local analysis of optical image sequences of the water surface to determine hydrographic parameter maps %U https://doi.org/10.1109/OCEANS.2000.882196 %X The appearance of the sea surface is a spatio-temporal phenomenon. Features observed on the water surface are, e.g. wave fields or wind streaks. The acquisition and analysis of image sequences therefore allows a complete (spatio-temporal) representation of the sea state. Ship- or land-based nautical radars are used in the field and optical sensors are used in hydraulic wave tanks to acquire image sequences. A technique using a combination of image sequences acquired from CCD cameras and in situ data sets is used to observe and analyze the spatio-temporal sea surface wave field in a hydraulic wave tank. A new image sequence processing method, called DiSC (Dispersive Surface Classificator), was developed to create maps of physical parameters for inhomogeneous, dispersive surfaces. The analysis technique allows the determination and representation of hydrographic parameters such as the near-surface current-velocity vector, the water depth, and the full-directional wave spectra. DiSC, applied to image sequences of the sea surface, is useful for impact studies on maritime structures, beach studies, and other studies in wave facilities. The analysis method also has been tested for nautical X-band radar image sequences. The presented method enables oceanographers and offshore and coastal engineers to study the spatio-temporal behaviour of wave fields in nature and in hydraulic wave tanks for monitoring and planning purposes. %0 conference lecture (invited) %@ %A Horstmann, J., Koch, W., Lehner, S., Tonboe, R. %D 2000 %J ERS-ENVISAT Symposium %T Mesoscale Wind Fields Retrieved from RADARSAT-I ScanSAR in View of ENVISAT ASAR %U %X %0 conference lecture %@ %A Horstmann, J., Lehner, S., Schulz-Stellenfleth, J. %D 2000 %J European Conference on Marine Science and Ocean Technology, EuroOcean 2000 %T Wind and Wave Measurements from Spaceborne Synthetic Aperture Radars %U %X %0 conference poster %@ %A Romaneessen, E., Lehner, S., Niedermeier, A., Horstmann, J. %D 2000 %J 6th International Conference on Remote Sensing for Marine and Coastal Environment %T Morphodynamic in the Elbe Estuary as Seen by ERS Synthetic Aperture Radar %U %X %0 conference lecture %@ %A Seemann, J., Senet, C.M., Ziemer, F. %D 2000 %J Mustererkennung 2000, 22. DAGM-Symposium, Informatik Aktuell %P 179-186 %T Local Analysis of Inhomogeneous Sea Surfaces in Coastal Waters using Nautical Radar Image Sequences %U %X %0 conference lecture %@ %A Hatten, H., Seemann, J., Bezuglov, A., Veremjev, V., Ziemer, F. %D 2000 %J Oceans 2000 %P 549-554 %T Determination of the Sea Surface Current Field out of the Doppler Shift of the Radar Backscatter Under Grazing Incidence %U %X %0 conference lecture (invited) %@ %A Horstmann, J., Koch, W., Lehner, S. %D 2000 %J ERS-ENVISAT Symposium %T High Resolution Wind Fields and their Variation Extracted from ERS-SAR %U %X %0 conference paper %@ %A Seemann, J., Senet, J., Wolff, U., Ziemer, F. %D 2000 %J Oceans 2000 %P 1329-1335 %R doi:10.1109/OCEANS.2000.881788 %T Nautical X-band radar image processing: monitoring of morphodynamic processes in coastal waters %U https://doi.org/10.1109/OCEANS.2000.881788 %X The morphodynamic processes in coastal areas are affected by tidal currents and the sea state, leading to transport of sand along the seafloor. Conversely, the tidal currents are influenced by changes in the bottom topography. The continuous observation of areas of high morphodynamic activity is important in order to warn of such changes in the flood stream situation and to avoid further change or loss of land. Therefore, there is urgent need for remote sensing methods which allow the retrieval of hydrographic parameters with high spatial resolution. Using a nautical X-band radar, image sequences of the water surface are acquired. The radar backscatter from the ocean surface is modulated by the surface wave field, and in addition in coastal areas by hydrodynamic interactions of the tidal current with the variable bottom topography. The bottom signatures are static during a single measurement, whereas the wave signature, whose spatio-temporal evolution is given by the dispersion relation of surface gravity waves, is dynamic. These signatures are separated by frequency filtering. A nautical X-band radar was mounted on the island of Sylt in the German Bight in the periods from February to June 1997 and from December 1998 to April 1999. The observed area is of high interest because morphological changes, altering the flood stream situation, have taken place in recent years and are still in progress. The static radar signatures have altered in a noticeable way between the two observation periods. A method was developed to estimate the near-surface current, the water depth and local surface-wave spectra from the dynamic radar signature, which is inhomogeneous in coastal areas due to the effects of wave refraction and diffraction, with high spatial resolution. %0 conference lecture %@ %A Senet, C., Braun, N., Lange, P., Seemann, J., Schymura, G., Ziemer, F. %D 1999 %J IGARSS 99, IEEE 1999 International Geoscience and Remote Sensing Symposium %P 387-389 %T Optical Image Sequence Analysis and Interpretation of Stationary and Instationary Wave Fields %U %X %0 conference lecture %@ %A Senet, C.M., Braun, N., Lange, P.A. %A , Seemann, J., Dankert, H., Ziemer, F. %D 1999 %J Proceedings of the Conference 'Algorithms, Devices and Systems for Optical Information Processing III' of the International Society for Optical Engineering, SPIE 1999 %T Image Sequence Analysis of Water Surface Waves in a Hydraulic Wave Tank %U %X %0 conference lecture %@ %A Senet, C., Seemann, J., Dankert, H. %A , Amoros Serret, J.R., Nieto Borge, J.C. %A , Ziemer, F. %D 1999 %J Proceedings of the HYDRALAB Workshop %T Optical Image Sequence Analysis and Interpretation of the Water Surface in a Multidirectional Wave Tank and its Application in Coastal Engineering %U %X %0 GKSS report %@ %A Petersen, W., Bloecker, G., Schroeder, F., Mehlhorn, N. %D 1999 %J Vom Wasser %P 37-50 %T Einfluss der veraenderten Schadstoffbelastung in der Elbe auf den Sauerstoffgehalt %U %X %0 journal article %@ 0143-1161 %A Schiller, H., Doerffer, R. %D 1999 %J International Journal of Remote Sensing %N 9 %P 1735-1746 %T Neural network for emulation of an inverse model – operational derivation of case II water properties from MERIS data %U 9 %X %0 conference lecture %@ %A Riethmueller, R., Heineke, M., Kuehl, H., Keuker-Ruediger, R. %D 1999 %J Intertidal Mudflats: Properties and Processes %T Influences of the local tidal flat conditions on the surface stabilisation through benthic diatoms %U %X %0 journal article %@ 0012-0308 %A Puls, W., Beusekom, J.van, Brockmann, U., Doerffer, R., Hentschke, U., Koenig, P., Murphy, D., Mayer, B., Mueller, A., Pohlmann, T., Reimer, A., Schmidt-Nia, R., Suendermann, J. %D 1999 %J Deutsche Hydrographische Zeitschrift / German Journal of Hydrography %N 2 / 3 %P 221-244 %T SPM concentrations in the German Bight: comparison between a model simulation and measurements %U 2 / 3 %X %0 conference lecture %@ %A Wolff, U., Seemann, J., Senet, C.M., Ziemer, F. %D 1999 %J IGARSS 99, IEEE International Geoscience and Remote Sensing Symposium 1999 %T The Analysis of Nautical Radar Signatures Generated by the Submarine Topography %U %X %0 conference lecture %@ %A Senet, C.M., Seemann, J., Dankert, H., Amoros Serret, J.R., Nieto Borge, J.C., Ziemer, F. %D 1999 %J 2nd Symposium on Operationalization of Remote Sensing , ITC %T Optical Image Sequence and Interpretation of the Water Surface in a Multidirectional Wave Tank and its Application in Coastal Engineering %U %X %0 conference lecture %@ %A Seemann, J., Senet, C.M., Dankert, H. %A , Hatten, H., Ziemer, F. %D 1999 %J Proceedings of the Conference 'Algorithms, Devices and Systems for Information Processing III' of the International Society for Optical Engineering, SPIE 1999 %P 536-546 %T Radar Image Sequence Analysis of Inhomogeneous Water Surfaces %U %X %0 conference lecture %@ %A Wolff, U., Seemann, J., Senet, C.M., Ziemer, F. %D 1999 %J 21. Symposium fuer Mustererkennung, DAGM 99, Informatik aktuell %P 372-380 %T Analysis of Morphodynamical Processes with a Nautical X-Band Radar %U %X %0 journal article %@ 0012-0308 %A Pohlmann, T., Raabe, T., Doerffer, R., Beddig, S., Brockmann, U., Dick, S., Engel, M., Hesse, K.-J., Koenig, P., Mayer, B., Moll, A., Murphy, D., Puls, W., Rick, H.-J., Schmidt-Nia, R., Schoenfeld, W., Suendermann, J. %D 1999 %J Deutsche Hydrographische Zeitschrift / German Journal of Hydrography %N 2/3 %P 331-353 %T Combined analysis of field and model data: A case study of the phosphate dynamics in the German bight in summer 1994 %U 2/3 %X %0 conference paper %@ %A Weinreich, I., Hauser, D., Lehner, S., Horstmann, J. %D 1999 %J Proceedings IEEE 1999, IGARS 99 %T Wind Speed From ERS SAR Images Compared With Ground Truth From the Fetch Experiment %U %X %0 GKSS report %@ %A Riethmueller, R., Heineke, M., Kuehl, H., Keuker-Ruediger, R. %D 1999 %J %T Potentials and limitations of chlorophyll a concentration as an index of sediment surface stabilisation %U %X %0 conference lecture %@ %A Horstmann, J., Lehner, S., Koch, W., Schulz-Stellenfleth, J., Tonboe, R. %D 1999 %J CEOS SAR Workshop, Abstract 19 %T Wind field retrieval over the ocean surface using synthetic aperture radars %U %X %0 conference poster %@ %A Petersen, W., Hennies, K., Kuehne, C. %D 1998 %J Gewaesserschutz im Einzugsgebiet der Elbe; 8. Magdeburger Gewaesserschutzseminar %P 121-122 %T Tranport von Schwermetallen in der Tideelbe in den Kuestenbereich: Bewertung der das Transportverhalten beeinflussenden Prozesse %U %X %0 conference lecture %@ %A Riethmueller, R., Hakvoort, H., Heineke, M., Heymann, K., Kuehl, H., Witte, G. %D 1998 %J Geological Society, Special Publications, Conference on Sedimentary Processes in the Intertidal Zone %P 283-293 %T Relating erosion shear stress to tidal flat surface colour %U %X %0 conference lecture %@ %A Petersen, W., Bloecker, G., Schroeder, F. %D 1998 %J Gewaesserschutz im Einzugsgebiet der Elbe; 8. Magdeburger Gewaesserschutzseminar %P 70-73 %T Chemische und biologische Prozesse bezueglich des Sauerstoff- und Naehrstoffhaushalts beim Uebergang der Elbe in den Tidebereich %U %X %0 journal article %@ 0003-2670 %A Gebhart, E., Mnich, U., Schroeder, F., Knauth, H.-D. %D 1998 %J Analytica Chimica Acta %P 263-273 %T Application of a new automatic event-controlled sampler for heavy metals: studies on the behaviour of particle bound heavy metals in the Elbe estuary %U %X %0 journal article %@ 1323-1650 %A Hakvoort, J. H. M., Heineke, M., Heymann, K., Kuehl, H., Riethmueller, R., Witte, G. %D 1998 %J Marine and Freshwater Research %P 867-873 %T A basis for mapping the erodibility of tidal flats by optical remote sensing %U %X %0 GKSS report %@ 0080-889X %A Hakvoort, J. H. M., Heineke, M., Heymann, K., Kuehl, H., Riethmueller, R., Witte, G. %D 1998 %J Senckenbergiana Maritima %N 1/6 %P 77-85 %T Optical remote sensing of microphytobenthic biomass: a method to monitor tidal flat erodibility %U 1/6 %X %0 GKSS report %@ 1385-1101 %A Petersen, W., Geisler, C.-D., Schroeder, F., Knauth, H.-D. %D 1998 %J Journal of Sea Research %P 179-191 %T AISIT: A new device for remote-controlled sampling of dissolved and particle-bound trace elements in surface waters %U %X %0 conference lecture %@ %A Ziemer, F., Seemann, J., Senet, C. %D 1998 %J 17th International Conference on Offshore Mechanics and Arctic Engineering %T Measuring and Predicting the Cruising in Natural Seas %U %X %0 journal article %@ 0170-2971 %A Schroeder, F., Knauth, H.-D. %D 1998 %J Spektrum der Wissenschaft %N 1 %P 114-118 %T MERMAID: ueberwacht Kuestengewaesser %U 1 %X %0 journal article %@ 0022-0981 %A Wiltshire, K. H., Harsdorf, S., Smidt, B., Bloecker, G., Reuter, R., Schroeder, F. %D 1998 %J Journal of Experimental Marine Biology and Ecology %N 1-2 %P 113-131 %T The determination of algal biomass (as chlorophyll) in suspended matter from the Elbe estuary and the German Bight: a comparison of HPLC, delayed fluorescence and prompt fluorescence methods %U 1-2 %X %0 conference lecture %@ %A Doerffer, R., Schiller, H. %D 1998 %J Oceans Optics XIV %T Determination of Case II Water Constituents using Radiative Transfer Simulation and its Inversion by Neural Networks %U %X %0 conference lecture %@ %A Doerffer, R., Schiller, H., Garcia, J. R., Regner, P. %D 1998 %J 2nd International Workshop on MOS-IRS and Ocean Colour %T First test of a two-step Neural Network Inverse Modelling Technique using MOS Data %U %X %0 conference lecture %@ %A Hakvoort, H., Doerffer, R. %D 1998 %J Oceans Optics XIV %T Optical closure for case II water %U %X %0 conference lecture %@ %A Hatten, H., Seemann, J., Horstmann, J., Ziemer, F. %D 1998 %J International Geoscience and Remote Sensing Symposium: Sensing and Managing the Environment %T Azimuthal Dependence of the Radar Cross Section and the Spectral Background Noise of a Nautical Radar at Grazing Incidence %U %X %0 conference lecture %@ %A Knauth, H.-D., Menzel, R., Schroeder, F., Nies, H., Grisard, K. %D 1998 %J Third European Marine Science and Technology Conference %T Variability of nutrient concentrations in the Elbe estuary and in the German Bight: Detection of wind-induced events and chemical-biological processes by quasi-continuous measurements %U %X %0 conference lecture %@ %A Nieto Borge, J.C., Ziemer, F., Seemann, J., Senet, C. %D 1998 %J 17th International Conference on Offshore Mechanics and Arctic Engineering %T Overcome of the Nyquist limit in Frequency in nautical radar measurement of wave fields %U %X %0 lecture %@ %A Schiller, H. %D 1998 %J %T Ausgewaehlte Methoden der Datenauswertung %U %X %0 conference poster %@ %A Petersen, W., Bloecker, G., Schroeder, F. %D 1998 %J International Symposium: Issues in Environmental Pollution (IEP) %T Oxygen Budget and Nutrients in the Elbe Estuary - Statistical Data Analysis and Process Modeling %U %X %0 conference lecture %@ %A Seemann, J., Senet, C.M., Hatten, H., Ziemer, F., Nieto Borge, J. C., Dittmer, J., Reichert, K. %D 1998 %J COST Conference, Provision and Engineering, Operational Application of Ocean Wave Spectra %T Analysis of Long Duration Radar Image Sequences %U %X %0 conference lecture %@ %A Seemann, J., Senet, C. M. %D 1998 %J Oceans '98 %T Analysis of inhomogeneous and instationary surface wave fields with radar and optical imaging sensors %U %X %0 conference lecture %@ %A Tanaka, A., Oishi, T., Kishino, M., Doerffer, R. %D 1998 %J Oceans Optics XIV %T Application of the Neural Network to OCTS Data %U %X %0 GKSS report %@ %A Wolfstein, K., Colijn, F., Doerffer, R. %D 1998 %J %T Photosynthesis/irradiance parameters of microphytobenthic algae from tidal flats in the German Wadden Sea %U %X %0 report part %@ %A Doerffer, R., Schiller, H. %D 1998 %J Algorithm Theoretical Basis Document ATBD 2.12, ESA Coc. No. PO-TN-MEL-GS-0005 %P 12 %T Pigment index, sediment and gelbstoff retrieval from directional water leaving radiance reflectances using inverse modelling technique %U %X %0 book part %@ %A Gehlsen, B., Kriebisch, R., Krasemann, H. L., Lamersdorf, W., Page, B. %D 1998 %J Heterogene aktive Umweltdatenbanken - Praxis der Umweltinformatik (Band 8) %P 163-179 %T Architektur und Benutzungsschnittstelle eines Zugriffssystems fuer heterogene, verteilte Umweltdaten %U %X %0 conference lecture %@ %A Lehner, S., Schulz-Stellenfleth, J., Horstmann, J. %D 1998 %J Euromech 387, Surface Slicks and Remote Sensing of Air-Sea Interaction %T Global Distribution of Sea Surface Features from ERS-2 SAR Wave Mode Data %U %X %0 book part %@ %A Puls, W., Beusekom, J.van, Brockmann, U., Doerffer, R., Hentschke, U., Koenig, P., Murphy, D., Mayer, B., Mueller, A., Pohlmann, T., Reimer, A., Schmidt-Nia, R., Suendermann, J. %D 1998 %J Abschlussbericht KUSTOS und TRANSWATT; Band 1 %P 213-254 %T Suspended matter regimes in the German Bight and the German Wadden Sea %U %X %0 conference lecture %@ %A Senet, C.M., Seemann, J., Ziemer, F. %D 1998 %J Euromech 387, Surface Slicks and Remote Sensing of Air-Sea Interactions %T Hydrographic Parameter Maps Determined From Optical Image Sequences of Dynamic Water Surfaces %U %X %0 GKSS report %@ %A Seemann, J. %D 1997 %J %T Interpretation der Struktur des Wellenzahl-Frequenzspektrums von Radar-Bildsequenzen des Seegangs (Dissertation) %U %X %0 conference lecture %@ %A Senet, C. M., Seemann, J., Ziemer, F. %D 1997 %J Oceans '97: 500 Years of Oceans Explorations %P 66-72 %T An Iterative Technique to Determine the Near Surface Current Velocity from Time Series of Sea Surface Images %U %X %0 conference lecture %@ %A Seemann, J., Ziemer, F., Senet, C. M. %D 1997 %J Oceans '97: 500 Years of Ocean Exploration; Conference Proceedings %P 1148-1154 %T A Method for Computing Calibrated Ocean Wave Spectra from Measurements with a Nautical X-Band Radar %U %X %0 conference lecture %@ %A Seemann, J., Ziemer, F. %D 1995 %J Proceedings of the OCEANS '95 MTS/IEEE „Challenges of our Changing Global Environment“ %P 1128-1133 %T Computer simulation of imaging ocean wave fields with a marine radar %U