Influence of coastal upwelling on chlorophyll a concentration in the surface water along the Polish coast of the Baltic Sea

Space-time variations in chlorophyll a (Chl a) concentrations in the surface water of upwelling regions along the Polish coast of the Baltic Sea were analysed. Carried out between 1998 and 2002 in the warmer season (from April till October), the measurements were targeted mainly at the Hel upwelling. Satellite-derived sea surface temperature (AVHRR) and Chl a data (SeaWiFS) were used. Generally speaking, the Chl a concentration increased in the upwelling plume, except along the Hel Peninsula, where two scenarios took place: a reduction in Chl a concentration in spring and an increase in autumn.