Abstract: An operational model system for the Baltic and North Sea with high resolution in the Western Baltic Sea

 

 

Authors: Stephan Dick, Frank Janssen

An operational model system is presented which has been used at the Bundesamt für Seeschifffahrt und Hydrographie (BSH) to predict water levels, currents, temperature, salinity, sea ice as well as dispersion of substances in the North Sea and Baltic Sea for many years now. Daily forecasts are computed by a three-dimensional baroclinic circulation model (BSHcmod) which runs on two interactively nested grids and is forced by the weather forecasts of the German Weather Service, tidal predictions and river runoff. Extension of the model system towards bio-geo-chemistry is under development. Since January 2008 a new version of the circulation model has been run operationally. In the new version the horizontal resolution has been increased to 900 m in the western Baltic Sea and the German Bight, and to 5 km elsewhere. Other advantages compared to the former version are a much higher vertical resolution and a new in-house developed adaptive vertical co-ordinate system. The specification of 'general vertical co-ordinates' used in the BSH model provides a better representation of internal dynamics using weakly inclined flexible material surfaces. Results in the western Baltic Sea are presented and compared to observations of water level, salinity and water temperature.