Swell hindcast statistics for the Baltic Sea

Abstract. The classic characterisation of swell as regular, almost monochromatic, wave trains does not necessarily accurately describe in water bodies shielded from the oceanic climate. In such enclosed areas locally generated waves still contribute to processes at air and seabed interfaces, their presence can be quantified by partitioning components based on speed relative wind. We present statistics for semi-enclosed Baltic Sea using 20 years swell-partitioned model data. significant height was mostly under 2 m, winter (DJF) mean typically less than 0.4 m; higher found limited nearshore areas. Swell were short (under 5 s), with periods over 8 s being rare. open-sea average ratio energy (to total energy) below – significantly World Ocean. Certain coastal dominated half time, because weak winds (U<5 m s?1) rather high heights. Swell-dominated events a 1 lasted 10 h. A cross-correlation analysis indicates that open sea is local wind when decays (dominant time lag roughly 15 h). Near coast, however, results suggest partially detached waves, although weather system generates them highest arrives h delay after low-pressure has already passed.