Peculiarities of the Settling Temperature in the Upper Water Layer of the Black Sea during Invasions of Cold Air

Abstract

Based on the results of drifter observations in the western Black Sea, it is shown that winter intrusions of cold air (ICAs) are accompanied by wind of 10 m/s in speed and by a decrease in temperature of the upper mixed layer (UML) by 0.1–0.2°C per day. Notably, the seasonal thermocline (ST) and cold intermediate water deepen, whereas after the ICA stops, these layers ascend to lower depths, causing settling of the lower temperature of the UML (while higher than the one relative to the period before the ICA) in the layer beneath ST. This process of the upper layer mixing is explained by the role played by mesoscale anticyclones.