Winter Circulation and Convection in the Antalya Basin (Eastern Mediterranean)

Abstract

From an oceanographic survey of the Antalya Basin in February 1997 the following horizontal circulation pattern was found: the Asia Minor Current (AMC) was detached from the Turkish coast flowing to the southwest. The Cilician Current was present and feeding the AMC. The AMC exhibited meander wavelengths of about 100 km and phase speed circa 10 cm s?1. A train of cyclonic eddies was located at the southern flank of the AMC. The central part of the Antalya Basin was occupied by the Antalya anticyclone. A second anticyclone farther west was identified as the Anaximander anticyclone. From a comparison with previous surveys it is concluded that the circulation of the Antalya Basin is controlled by the position of the AMC. The circulation is cyclonic if the AMC flow path is confined to the coast, and anticyclonic if the path is distant from the coast. In the latter case, the anticyclonic flow may force the Cilician Current to reverse its direction. A nearly homogeneous pool of Levantine Surface Water was found trapped within the Antalya anticyclone. It is shown that even under light wind conditions, thermohaline convection down to about 200-m depth takes place in this pool. It is speculated that the convectively mixed water body is subject to further transformation by double diffusive mixing with the underlying water and finally contributes to the formation of Levantine Intermediate Water. This is supported by calculations of the necessary double diffusive heat and salt fluxes, which are on the right order of magnitude.