A.B. Polonsky1,2, N.S. Drobosuk2
1 Institute of Natural end Technical Systems, Russian Federation, Sevastopol, Lenin St., 28
2 Sevastopol Branch of Moscow State University, Russian Federation, Sevastopol
The paper is devoted to the complex analysis of daily satellite data on sea surface temperature (SST) in the Black Sea from early 1980s and wind field from 1988. It is shown that abrupt Black Sea SST decrease (between 2 to 9°С per day) is a regular phenomenon. Such SST decreasing is typical not only for the coastal upwelling zones in spring-summer. Extended areas of such type arise in the vicinity of the western and eastern large-scale cyclonic gyres in the Black Sea. Transient (but not too fast) cyclonic atmospheric eddies passing through this region are the main cause of additional turbulent entrainment, upward motion in the upper sea layer and SST anomalies generation. These anomalies are usually developed during a few days after stormy conditions. This mechanism is especially efficient when the extended blocking is formed over N-E part of Europe and cyclones are slowly moving along its periphery. Coefficient of correlation between cyclonic wind vortices and consequent regional SST decreasing in the eastern cyclonic Black Sea gyre exceeds 0.6. Frequency of the abrupt SST fall and anomalous area tend to be higher during recent 20 yrs as a result of intensified cyclonic activity in the Black Sea region since 1990s.
Keywords: sea surface temperature, wind field, satellite data, cyclonic vorticity in the low-troposphere.
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