A model-measurements comparison of atmospheric forcing and surface fluxes of the Baltic Sea

Observed basic meteorological quantities, heat and radiationfluxes from three different measurement stations in the BalticSea are compared with model data of the coupled sea-ice-oceanmodel BSIOM in order to evaluate the atmospheric forcing, correspondingsurface fluxes and the sea surface response. Observational datawere made available from the BASIS winter campaigns in 1998 and2001 as well as from the r/v "Alkor" cruise in June 2001. Simulatedfluxes were calculated from prescribed atmospheric forcing providedfrom the SMHI meteorological database and modelled sea surfacetemperatures. The comparison of these fluxes with observationsdemonstrates a strong correlation, even though mean differencesin sensible heat fluxes range from 4 to 12 W m-2 in winter and-25 W m-2 in the June experiment. Differences in latent heatfluxes range from -10 to 23 W m-2. The short-wave radiationflux used as model forcing is on average 15 W m-2 less thanthe corresponding observations for the winter experiments and40 W m-2 for the June experiment. Differences in net long-waveradiation fluxes range from -5 to 12 W m-2 in winter and-62 W m-2 for the June experiment.The correspondence between measured and calculated momentum fluxes is very high, which confirms theusability of our model component for calculating surface windsand wind stresses from the atmospheric surface pressure