An operational model for Lithuania's coastal zone

The results of testing (hindcast) an operational hydrodynamic model HIROMB_LT for Lithuania's coastal zone are presented and analysed in this paper. A model is developed using the program code of an opera- tional hydrodynamic model of the Baltic Sea HIROMB (Swedish Meteorological and Hydrological Institute). The model grid (horizontal resolution 300m, vertical resolution 25 layers) covers the Baltic Sea coastal area until the Gdansk Bay in the West and Latvian border in the North and the Curonian Lagoon. The model simu- lated water levels, surface water temperature surface water salinity and ice cover variables were tested against measurements for the year 2009. The model shows satisfactory performance on water level and temperature and rather weak performance on salinity at stations where good reproduction of the mixing of fresh and saline water is critical (Juodkrantė and Klaipėda seaside stations). The model performance on ice thickness is still problematic because of too coarse spatial resolution of westerly winds. Despite of these shortcomings, the model can be used for operational forecasts already; however, data assimilation may be necessary for salinity and ice thickness.