Long-term hindcast simulation of sea ice in the Baltic Sea

The data set contains the results of numerical modeling of sea ice over a period of 50 years (1958-2007) in the Baltic Sea. A long-term hindcast simulation was performed using a three-dimensional hydrodynamic model PM3D (Kowalewski and Kowalewska-Kalkowska, 2017), a new version of the M3D model (Kowalewski, 1997). A numerical dynamic-thermodynamic model of sea ice (Herman et al. 2011) was coupled to the analysis of ice conditions variability. The model is based on the Princeton Ocean Model (POM) developed at Princeton University (Blumberg and Mellor, 1987). Like POM, the M3D/PM3D model uses the Mellor-Yamada turbulence scheme and sigma vertical coordinates. The simulation was carried out in a rectangular grid of 3' (latitude) and 6' (longitude) resolution. The spatial resolution was 3 nautical miles, i.e. about 5.5 km. An open boundary was located between the Skagerrak and the Kattegat along the parallel connecting Skagen and Göteborg, where the water exchange with the North Sea takes place. A radiation condition based on Somerfield’s concept for velocities vertically averaged and normal to the boarder plane was applied. Atmospheric forcing for the period 1958-2007 was performed using the regional at amospheric climate model REMO (REgional MOdel) which was based on the numerical weather prediction model EM (Europa-Model) of the German Weather Forecast Service (DWD). Daily spatial distributions of sea ice thickness and concentration were recorded in the model's computational grid in unprojected form (LatLong, WGS 84, EPSG: 4326). Ice thickness is expressed in meters and ice concentration (fraction) is expressed as the ratio of the ice covered area to the total area of the grid. The results of quantitative comparisons between simulated ice concentrations and satellite data (Herman et al. 2011) were considered satisfactory.