Framework GCOAST

The Helmholtz-Zentrum Hereon has developed the GCOAST (Geesthacht Coupled cOAstal model SysTem) coupled modelling framework, flexibly integrating the most important key components of regional and coastal modelling and, additionally, allowing to include information from observations. The main advantage of coupling is to allow coupled models to interactively exchange, during runtime, a variety of simulated fields that should otherwise be approximated. The GCOAST domain covers the North Atlantic Shelf region, the North and the Baltic Sea. For CoastalFutures, it is forced by downscaled global climate change scenarios data from the Coupled Model Intercomparison Project Phase 6 (CMIP6) suite for the last and the current century.

Physical processes taking place in the Atmosphere, Ocean and Waves are investigated through runs coupling the COSMO-CLM atmospheric model, the NEMO ocean model and the WAM wave model. In particular, the properties and the response of the three compartments on regional to transregional scales to the changing environmental conditions on climatological time scales will be analysed. Furthermore, for the Souhern North Sea, the local effects of specific anthropogenic changes (e.g. wind farms) on decades time scale are studied through coupled ocean-waves higher resolution runs. This allows to take into account physical interactions not captured by coarser resolution models. In addition, runs will be conducted that fully couple one of two atmospheric models, COSMO-CLM or ICON-CLM, the hydrologic discharge model HD, and the ocean model NEMO, which close the water balance in the regional Earth system.

For the analysis of biogeochemical processes, runs coupling the Ocean model NEMO and the biogeochemical model ECOSMO-E2E are carried out. ECOSMO-E2E is a functional group type model that resolves the major nutrient cycles in the system as well as lower and higher trophic production including fish and macrobenthos. The ecosystem model dynamics are coupled through the Framework for Aquatic Biogeochemical Models (FABM) to facilitate the coupling with NEMO.

HydroPy model provides riverine input of fresh water and nitrogen into the ocean. This model represents a further development of the Max-Plank-Institute Hydrological Model (MPI-HM). Read further: https://zenodo.org/record/4730160#.YtkFS99CRPY

HydroPy model provides riverine input of fresh water and nitrogen into the ocean. This model represents a further development of the Max-Plank-Institute Hydrological Model (MPI-HM). Read further: https://zenodo.org/record/4730160#.YtkFS99CRPY

Grafic: H. Weidemann/ Hereon

To address food web related questions in the Baltic Sea, we developed the 3d coupled ecosystem model ECOSMO E2E (Daewel and Schrum, 2016), which is an NPZD-Fish modelling approach that bases on the ecosystem model ECOSMO II (Daewel and Schrum, 2013). The model represents both fish and macrobenthos as functional groups that are linked to the lower trophic levels via predator-prey relationships (Figure). The model allows investigating bottom-up impacts on primary and secondary production and cumulative fish biomass dynamics, but also bottom-up mechanisms on the lower trophic level production. More: https://www.hereon.de/institutes/coastal_systems_analysis_modeling/matter_transport_ecosystem_dynamics/models/index.php.en

Grafic: Daewel et al. 2015 (Fig.2)

The early-life history of marine fishes is one of the main determinants of the recruitment variability and an important bottleneck in the adaptation of fish populations to changing climate and anthropogenic disturbances. Individual-based models (IBMs) that simulate the behavior of an individual fish and its interactions with the biotic and abiotic environment are widely used in fisheries science to study starvation, predation and dispersal mortality of fish early-life stages. In CoastalFutures, we are using stand-alone or coupled larval IBMs to better understand how natural and anthropogenic stressors affect mortality and survival of larval fish in the vicinity of the spawning and nursery areas of the commercially important fish species in the North and the Baltic Seas. more: https://www.hereon.de/institutes/coastal_systems_analysis_modeling/matter_transport_ecosystem_dynamics/models/index.php.en

OSMOSE is a multi-species and individual-based model (IBM) for fish species. Here, the model represents 12 species (pelagic and benthic: Sole, Haddock, Sprat, Saithe, Dab, Sandeed, Herring, Plaice, Cod, Pout, Gurnard and Whiting) of economic interest in the North Sea. The model assumes opportunistic predation based on spatial co-occurrence and size adequacy between a predator and its prey. OSMOSE represents major processes of fish life cycle (growth, reproduction, migration, and mortality). Fish individuals are grouped into schools or ‘super-individuals’ which are characterized by their size, weight, age, species, and geographical location. OSMOSE is a 2D model (horizontal representation) which have a resolution of 10km grid on the horizontal and run with a two-week’s time step. To provide prey field to the fish, OSMOSE is coupled to hydrodynamic and biogeochemical models, here NEMO-ECOSMO. In output, a variety of size-based and species-based ecological indicators are produced at different levels of aggregation: at the species level (e.g. mean size, mean size-at-age, maximum size, mean trophic level, within-species distribution of trophic level), and at the community level (e.g. slope and intercept of size spectrum, Shannon diversity index, mean trophic level of catch). more: https://osmose-model.org/

This module of wind farm parameterization in the regional climate model COSMO-CLM1 allows the simulation of wind farms on a large spatial and temporal scales. The use of this module in COSMO-CLM allows to study the impact of wind farms on regional climate, air-sea fluxes, and power generation.