Modelling the hydrodynamics of the Southern Bight of the North Sea: Skills assessment of different configurations (i.e. nesting) in the perspective of coupling with sediment transport

The impact of offshore wind farm installation and dredging activities on the spatial distribution and dynamics of sediment grain size, biogeochemistry and biodiversity will be estimated in the Southern Bight of the North Sea (SBNS) with a focus on the Belgian Coastal Zone (BCZ) in the frame of the FaCE-It research project (Functional biodiversity in a Changing sedimentary Environment: Implications for biogeochemistry and food webs in a managerial setting).
The three-dimensional hydrodynamical model ROMS-COAWST was implemented for simulation of the complex hydrodynamics of SBNS and sediment transport. The first level of nesting with the resolution of 1 km was used in the area of Belgian Economical Zone. In order to reach a fine resolution of 250 m in the BCZ, the second level of nesting will be used. Six-hourly ECMWF ERA-interim meteorological data was used to force the model at the sea-air boundary and the coarse resolution model results available from Copernicus Marine Environment Monitoring Service were used to force the model at the open boundaries. Tides and rivers were also considered.
Next types of long-run simulations have been conducted: a 10-years climatological simulation and an interannual simulation over 2004-2013 in order to investigate the interannual dynamics. The model accuracy was evaluated through validation of its outputs against observed salinity, temperature and currents data (remote sensing and in-situ).
Results validation of currents and temperature and salinity horizontal fields and vertical profiles against available satellite fields and in-situ data, i.e. from the project field campaign, is conducted and discussed. Application of the nested grid and its benefits for results accuracy is also presented.