Improving Baltic Sea wave forecasts using modelled surface currents

Abstract Currents in the Baltic Sea are generally weak, but during strong winds they can grow high enough to affect surface wave propagation and evolution. To evaluate significance of wave-current interactions Sea, we conducted a study using model WAM, comparing run without currents one with current forcing from NEMO hydrodynamical simulation. The overall changes field caused by were quite small. Changes over 10 cm significant height (SWH) or 1 s peak period ( T p ) occurred only some areas typically less than 3% time. Current refraction changed SWH annual mean up 2 cm, 60 seen maximum values. had occasionally large due shifts energy two-peaked swell wind-sea spectra. Including led stronger compared wind sea energy. A comparison buoy Gulf Finland showed that this change improved accuracy simulation narrow gulf. Current-induced was most prominent near coastal areas, where speed exceeded 0.3 m/s. In general, decreased slightly increased adjacent open areas. effects frequent Finland, Western Gotland Basin Åland Sea.