Advancements in the Ongoing Development of the Black Sea Physical Analysis and Forecasting System

The Black Sea Physical Analysis and Forecasting System (BSFS) operates within the Black Sea Monitoring and Forecasting Centre (BLK-MFC) as part of the Copernicus Marine Service (CMEMS). Here we present ongoing research and development activities for the future generations of the BSFS. The current system has the 1/40-degree horizontal grid NEMO ocean model featuring 121 vertical levels. Significant enhancements encompass the integration of biharmonic horizontal viscosity instead of the traditional Laplacian constant viscosity. This adaptation effectively mitigates small-scale grid noise, thereby elevating accuracy in representing mesoscale eddies. A notable advancement includes the implementation of a two-way nested domain surrounding the Bosphorus Strait, employing the NEMO-AGRIF mesh refinement algorithm. This newly constructed high-resolution Bosphorus Strait domain has a 1/200-degree horizontal resolution, facilitating much better resolution of the strait's bathymetry. Further refinements encompass recent developments targeting improvements in the model's eddy kinetic energy (EKE), relative vorticity fields, and minimized drift below the thermocline which is crucial for longer integration in a reanalysis scope. A concurrent effort involves the ongoing development of a new domain encompassing the Azov Sea, coupled with a sea-ice model. This initiative involves the utilization of different bulk formulas, enabling the incorporation of sea ice fluxes and AGRIF mesh refinement capabilities. Testing of the enhanced domain configuration involves rigorous assessments aimed at validating the efficacy of these updates, ensuring a comprehensive evaluation of the system's performance.