Regional Features of the Temperature Field Synoptic Variability on the Black Sea Surface from Satellite Data

Purpose. The aim of the work is to clarify the regional features of synoptic variability of the Black Sea surface temperature, to reveal its intra- and inter-annual changes and to assess the features' relations with the large-scale atmospheric processes. Methods and Results. The satellite-derived data on the sea surface temperature in 1982-2018 from the Copernicus array were used; their temporal resolution was daily average and the spatial one - 0.04 degrees. These data showed that the maximum of temperature synoptic variability was observed in the coastal part of the northwestern shelf from the Dnieper-Bug estuary to the Danube delta, in the Karkinit Bay and in the Kerch Strait. In the deep sea, strong synoptic variability can be observed in the regions of the Eastern cyclonic gyre and the Batumi anticyclone. The greatest contribution of synoptic variability to the total temperature dispersion was observed in the Kerch Strait and to the south of the Kerch Peninsula. The level of multi-year average synoptic variability is lower or comparable with the level of the interannual variability in most of the water area, except for the Kerch Strait, the northwestern and the Bosporus shelves. It is revealed that in the climatic annual cycle the main maximum of synoptic variability is observed in May, a month before the maximum rate of surface water heating is achieved, the second maximum - in October, a month before the maximum rate of water cooling. The minimums are observed in February-March, during the period of maximum cooling of surface waters, and in August, during their maximum heating. Noticeable interannual changes of the level of temperature synoptic variability varying from -0.3 degrees C . to 0.3 degrees C, were revealed. Conclusions. Synoptic variability of the Black Sea surface temperature is characterized by noticeable intra-annual and interannual variations. Its climatic annual cycle is of a semi-annual periodicity due to the processes of water cooling and heating. The maximum increase of the synoptic variability level on the interannual scale is observed after 2003 on the northwestern shelf. Significant correlation with the indices of the North Atlantic, East Atlantic and the East Atlantic-West Russia oscillations was not revealed.