Mediterranean thermohaline properties and large-scale climatic patterns

The link between variations of the wintertime large-scale climatic patterns and thermohaline properties of the Mediterranean Sea was studied using correlation coefficients and the difference of the patterns between positive and negative modes. High NAO index is associated with the higher (lower) water temperature in the western (eastern) basin, less precipitation as well as sea level height; and increase of the net evaporation, northerlies and buoyancy flux particularly over the northern part of the basin. Some differences in the relationship between NAO index and oceanographic conditions in the Mediterranean sub-basins have also been evidenced. More specifically, the sea level in the North Ionian gyre is not influenced by NAO. The temperature in the west Alboran Sea is out of phase with the index in spite of the positive correlation in the western basin. In addition, the warmer water in the eastern coasts of the Sicily during the NAO+ is not related to the surface heat fluxes. NAO doesn’t have a weak impact on the SST of the Adriatic sea although the heat gain is more pronounced during the positive NAO. EA pattern reveals a strong influence on the Western Mediterranean and the negative phase of this index is associated by the stronger winter convection. The influence of MOI is more evidenced in the eastern basin by the lower temperature due to heat loss intensification during the positive MOI.