Winter convection continues in the warming Southern Adriatic

During winters in the eastern Mediterranean, cold winds blow over the waters of the southern portion of the Adriatic Sea, resulting in heat loss of the ocean. This cold surface water becomes denser than surrounding waters and sinks into the deep reaches of the Mediterranean Sea. This forms ‘deep water,’ or water once at the ocean’s surface that now has sunk to depths of 1500 meters and more. The Southern Adriatic Pit (SAP) is the convection site and source for the Eastern Mediterranean Deep Water (EMDW). Since the late 1980s, the SAP has been monitored almost every year because of its importance in driving the eastern Mediterranean deep circulation convection cell. This article presents data from a 26 March – 8 April 2005 oceanographic cruise that shows the occurrence of deep convection in this area down to a depth of 800 meters. The article indicates that in the last decade, the water entering the Southern Adriatic from the rest of the eastern Mediterranean has been getting warmer, causing buoyancy to increase. This increase in buoyancy could play a major role in depressing this convection when the heat loss is limited, such as in mild winters. Indeed, convection did not occur every year during the time span considered in this paper (between 1997 to 2005). However, this study documents that, despite the increase of buoyancy, convection did occur in some winters. The fact that the winter convection continues to take place although the waters are more buoyant suggests a remarkable sensitivity of the SAP to the climatic regime of the area.