Response of the Black Sea Upper Layer to the Cyclone Passage on September 25–29, 2005

Abstract

The response of the Black Sea upper layer to the quasitropical cyclone on September 25–29, 2005 is studied using the coupled model consisting of the WRF atmosphere model, NEMO ocean model, and OASIS coupler. The circulation arising in the sea under the influence of the quasitropical cyclone is considered. It is demonstrated how sea surface temperature varied under the cyclone during its evolution and movement. The possible mechanisms of the significant (by >10°С) temperature drop under the cyclone are analyzed. It is shown that the main reason for the sea surface cooling is upwelling, i.e., the cold water lifting from the thermocline to the sea surface, and heat exchange with the atmosphere has an insignificant effect on the temperature variation. It is also demonstrated that the value of the sea surface temperature anomaly simulated by the coupled modeling is consistent with observational data much better than the results of atmospheric reanalysis and marine reprocessing.