Peculiarities of the water dynamics and chlorophyll a distribution in the northeastern part of the Black Sea in Autumn 1997

The analysis of thirty-one infrared images from NOAA satellites (September 6-November 14, 1997) revealed the formation and movement of five near-shore anticyclonic eddies (NAEs) within the region between Tuapse and the Kerch Strait during the period from September 6 to October 8. In addition, an are a of cold water (zone of divergence) occurred throughout the whole period o f observations between the Rim Current and the anticyclones in the center o f the eastern part of the Black Sea. This zone included one or two cyclones with diameters of about 40 km. The temperature contrast between this zone and the warm near-shore flow was as high as 6.5 degrees C. Over some parts of the trajectory, the velocity of the movement of the NAEs about 40 km in diameter was as high as 15 cm/s. The transformation of an NAE formed west o f Novorossiisk into a deep-sea eddy was traced. The hydrographic measuremen ts from RN Akvanavt (November 12-15, 1997) revealed the surfacing of the is opycnals within the zone of divergence and their deepening toward the cente r of the eastern basin. Increased chlorophyll a concentrations las compared with the mean concentration in the center of the eastern part of the sea) were noted on October 8, 1997 from the data of the SeaWiFS radiometer in fo ur "young" NAEs and in the zone of divergence. A reduced chlorophyll a conc entration occurred in the "old" NAE tone month old) transformed into an ope n-sea eddy.