WATER EXCHANGE IN THE POMERANIAN-BIGHT INVESTIGATED BY SATELLITE DATAAND SHIP-BORNE MEASUREMENTS

The Pomeranian Eight is characterized by the main freshwater input int o the western Baltic Sea coming from the Oder and Peene rivers. The ra te of river discharge is driven by varying sea level in the southern B altic, and the distribution patterns of the river plume are dominated by the local wind. This study uses daily available sea surface tempera ture (SST) maps (4-6 times a day), derived from Advanced Very High Res olution Radiometer (AVHRR) data of the NOAA satellites, to investigate these patterns in relation to the meteorological conditions. Comparis ons of SST maps with shipborne measurements for different wind situati ons confirm the usability of satellite data for investigation of the r iver discharge. On the basis of about 125 available NOAA scenes scatte red over all seasons in the period of 1991-1994, typical horizontal di stribution patterns were derived for wind directions of the eight octa nts. Chlorophyll concentration maps derived from Coastal Zone Colour S canner (CZCS) data of the NIMBUS-7 satellite are, in special cases, mo re detailed than corresponding SST patterns (channel 6). They confirm the patterns and the transport of suspended material. Long-term wind r ecords from the Arkona weather station indicate the dominant wind dire ctions and the seasonal variations in Wind forcing leading to seasonal preferred patterns and transport directions of the river plume into a nd out of the bight. Dominant westerly winds in summer, autumn and win ter produce an eastward transport along the Polish coast into the Born holm Sea and further into the Gdansk Bay over more than 300 km. fn the period of the main freshwater inflow in spring, easterly winds are do minant and transport the river water along the German coast into the A rkona Sea. This is confirmed by high accumulation rates at the bottom of the Arkona Basin. The results of these investigations allow a predi ction of distribution patterns and main transport directions in relati on to the prevailing wind situation. Copyright (C) 1996 Elsevier Scien ce Ltd.