The Extreme Winter Cooling of the Black Sea

V. V. Efimov, A. O. Savchenko, and A. E. Anisimov

The analysis of the features of the extreme winter cooling of the Black Sea is carried out using the high-resolution regional reanalysis dataset for the period of 1958–2007. Obtained are the quantitative estimates of heat fluxes in the area of the maximum cooling in the northwestern part of the sea. The temporal variability of heat fluxes is analyzed. Estimated are the statistical characteristics of extreme values which contribute significantly to the total winter cooling. It is demonstrated that the variations of the values of extreme heat fluxes and the extreme flux frequency are in the statistically significant antiphase relationship with the North Atlantic Oscillation index. The temperature–pressure composites are considered and the synoptic conditions leading to the formation of extreme heat fluxes are identified. Given are the satellite images of cloudiness corresponding to the composites and illustrating cold air invasion through the northern boundary of the sea.