Formation of Positive Sea Surface Temperature Anomalies in the Black Sea

Abstract

Based on the satellite data at the points of a high-resolution regular grid for the period from 2008 to 2021, positive anomalies of the sea surface temperature (SST) in the northern Black Sea and off the southwestern coast of Crimea have been identified. It has been shown that there are vast areas with an exceeding of SST over the mean for the measurement period up to 4–5 and 5–6°C and a monthly total area (for example, in May 2018) about 200000 and 100000 km², respectively, in the northern Black Sea. The analysis of available satellite data has led to the conclusion that warm SST anomalies occur mainly in May and October. The maximum (over the entire analyzed period) warm SST anomaly (exceeding 5°C) was reached in May 2012, when its area was 200000 km². The spatial structure and some statistical characteristics of the identified SST anomalies have been described and analyzed. It has been shown that the typical frequency of vast SST anomalies is at least one case per several years, while they are generated by abnormal heat fluxes on the sea surface with the inflow of anomalously warm river water in shallow areas of the northwestern shelf and spread to the open sea areas due to the horizontal advection of predominantly wind-driven origin. The average annual SST anomalies off the northwestern coast of Crimea and in the northern Black Sea correlate at a level of 0.97.