GCOAST Applications
Examples for the application of GCOAST
- Atmosphere-Ocean-Waves Interactions
- Dynamics and Fluxes at the Land-Sea Transition
- The Coupling of the Marine Hydrosphere and Biosphere
- GCOAST ESM Model Configuration
Atmosphere-Ocean-Waves Interactions
Grafics: Ha Hagemann/Hereon
Wiese et al. (2019) studied the effects of the coupled COSMO-CLM/WAM models on the atmospheric planetary boundary layer. The improved prediction of wave height and surface winds by applying a coupled atmosphere/wave model was shown by Wahle et al. (2017). It has been demonstrated that coupling between waves and ocean models increase the sea level in the coastal areas (Staneva et al., 2017, Ponte et al., 2019), changes sea temperature and salinity (Alari et al., 2016, Schollen et al., 2017, Staneva et al., 2018), mixing and ocean circulation (Staneva et al., 2017), upwelling (Wu et al., 2019), leading to better agreement with in-situ and satellite measurements (Staneva et al., 2017, Cavaleri et al., 2018; Staneva et al., 2019).
Dynamics and Fluxes at the Land-Sea Transition
Grafics: Ha Hagemann/ Hereon
Comparisons with available atmospheric and oceanic observations also showed that the use of the coupled system reduces the prediction errors in the coastal ocean especially under severe storm conditions (Mey-Frémaux et al., 2019, Staneva et al., 2019, Lewis et al., 2019) and is of crucial importance for drifter simulations (Staneva et al., 2018). The internal model variability is pronouncedly reduced during extreme events such as heavy storms when coupling atmosphere, hydrology, ocean and sea ice models (Ho-Hagemann et al., 2020) or when coupling atmosphere and wave models (Wiese et al., 2020).
ECOSMO-EST
ECOSMO-EST refers to ecosystem modelling with ECOSMO in an estuarine context including lagoons, tidal flats and other shallow water areas with wet-dry dynamics. This branch is based on a coupling of ECOSMO with SCHISM as a hydrodynamic core via the FABM coupling interface and was initially developed for application in the Elbe estuary of the North Sea (Pein et al., 2021). The framework allows for wetting-and-drying that is typical for tidally influenced areas as well as a flexible combination of lateral inflows of water volumes, optionally with temporally varying nutrient concentrations. Recently, ECOSMO-EST has been extended by deepening the coupling with the hydro-sedimentological core model by including the shading of phytoplankton by inorganic sediments and the adsorption of phosphate by sediments (Pein and Staneva, 2024). Due to the combination with SCHISM, ECOSMO-EST offers great flexibility in simulating marine environmental interfaces such as polders, small channels, tidal flats and even experimental geometries by seamlessly linking 2D and 3D computational grids (Pein et al., 2024).
The Coupling of the Marine Hydrosphere and Biosphere
Grafics: Ha Hagemann/ Hereon
In a study on biogeochemical processes in the Elbe estuary, Pein et al. (2019) demonstrated the systems capacity to simulate processes in a coupled hydrosphere-biosphere modeling framework. Multi-model couplings developed by Lemmen et al. (2018) have been, e.g., applied for assessing ecosystem impacts of offshore wind farms (Slavik et al. 2019).
GCOAST ESM Model Configuration
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.