The influence of sea-salt aerosols on the atmospheric extinction over the Baltic and the north seas

The results of spectral aerosol optical thickness measurements at the Polish coast (Sopot, Hel) carried out in the period from July 1997 up to May 1999 are presented. The empirical orthogonal function (EOF) method applied to aerosol optical thickness spectra allowed to distinguish three aerosol advections, associated with wind direction sectors: 290-30°, 30-70°, and 80-280°, corresponding to three main aerosol types: maritime or mixed (continental-maritime), continental, and the modified version of the continental aerosol type. The discrepancies between oceanic and the Baltic maritime aerosol type are investigated in terms of sea-salt aerosols size distributions including the North Sea experimental measurements.