Spatial patterns of quality of historical wave climate reconstructions for the Baltic Sea

We address the accuracy of replication of wave properties of the Baltic Sea using two wave climate simulations for the period of 1970–2007. Both are based on the spectral wave model, WAM, with a resolution of 3 nautical miles in hypothetical ice-free conditions. One of them used adjusted geostrophic wind fields from the Swedish Meteorological and Hydrological Institute database and the other applied high-resolution COSMO-CLM 4.8 winds. The outcome of both simulations is compared with available instrumentally measured wave heights. Simulations using geostrophic winds systematically underestimated wave heights, whereas the hindcast using COSMO winds tended to overestimate wave heights. The simulation with COSMO winds provides an acceptable match with measured data in the entire sea. The hindcast forced with geostrophic winds is only adequate at the latitudes of the Gulf of Finland.