Anticyclonic eddies in the northwestern Black Sea

National Oceanic and Atmospheric Administration (NOAA) Advanced Very-High Resolution Radiometer (AVHRR) imagery (1993, 1998), along with attendant daily meteorological information from seaports and available hydrographic information from different years, was used to investigate the structure and evolution of mesoscale anticyclonic eddies in the northwestern Black Sea, and their role in shelf/deep basin water exchange. In the summer of 1993, two anticyclonic eddies with diameters of 90 and 55 km coexisted without coalescence for 1.5 months over a wide and relatively gentle part of the northwestern continental slope. The directions of the eddiesʹ movements inside this zone (speed of movement up to 16 cm/s) were likely determined by the interaction between eddies themselves, and by the Rim Current meandering and forcing. For June–August of 1998, three such eddies have been traced in the sea surface temperature (SST, AVHRR) and chlorophyll a (SeaWiFS) fields. The largest anticyclone with a diameter of 90 km moved during 3 months southwestward from the wide slope region west of Sevastopol to the area of narrower slope southeast of Cape Kaliakra with a mean speed of about 3 cm/s. Together with nonstationary associated elements (cyclones at the eddiesʹ peripheries, entrained and ejected jets), anticyclonic eddies determine water exchange processes in a large area of the western Black Sea between 43–45°N and 29–33°E. They transport chlorophyll-rich coastal waters to the deep basin, westerly winds being favorable to the process.