Atlantic water in the strait of Sicily

Abstract

Historical and recently acquired hydrographic and current meter data are used to study the behavior and the annual cycle of the surface layer of Atlantic Water (AW) within the Sicilian Channel section of the Strait of Sicily. From January to March the surface layer isotherms and isohalines are much more steeply sloped toward the African coast. The transition from winter to summer stratification occurs during the April to May period, and by July both temperature and salinity isolines are quite horizontal. The seasonal variations in temperature and salinity can be characterized by corresponding values of mean velocity, mean kinetic energy, and eddy kinetic energy. During winter these values increased 2–3 times their summer values. Hydrographic and satellite data show that the stream of warmer and less saline AW enters the Strait of Sicily close to the Tunisian coast. South of Cap Bon, the AW appears to decelerate, forming meanders and detached parcels or small rings. These structures are seen in satellite images more often during winter than summer, when the AW current in the Strait of Sicily is more energetic.