Temperature-salinity structure and mixed layer in the Western Mediterranean Sea

Abstract

The hydrographic data taken during 1932 — 1985 were analyzed to present the mean temperature structure and the mixed layer in the different basins in the Western Mediterranean Sea. The data indicate that a surface mixed layer exists all year round in all basins with maximum depth reach to about 260m in the Gulf of Lions during February. The mixed layer depth (MLD) seemed to be more shallow in the Alboran Sea (average 50 m ) than other basins. The seasonal variation of mixed layer salinity (MLS) was seen as large amplitude of MLS in both Catalan Sea and Gulf of Lions, during the warm months. In Tyrrhenian Sea the MLS has a higher value than the sea surface salinity. Also, the effect of Atlantic water was clearly identified in the Alboran and Algerian Seas. The mixed layer temperature (MLT) is significantly related to temperature values down to 250 m in the northwestern Mediterranean basins during the cold months. The correlation's of MLD with temperature are insignificant in all basins during the warm months. The anomalies of MLT, MLS and MLD showed that the temperature and thickness of the mixed layer have a week inverse correlation. Finally, the seasonal variations of the heat content of the mixed layer in all basins in the Western Mediterranean are described.