Mediterranean Oscillation and its relationship to salinity fluctuation in the Adriatic Sea

Abstract

        To find out what meteorological conditions are favourable for the inflow of LIW into the Adriatic, atmospheric pressure fluctuations from an area larger than the Mediterranean (from Mid-North Atlantic to Southeastern Mediterranean), have been analysed for the period 1900-1995 at the annual scale. The response of the Adriatic Sea, to the hemispheric climatic changes, described by the NAO index, was also analysed. The PC (Principal Component) analysis of the pressure field resulted with different modes of variability, and enabled locating the pressure areas directly related to the inflow phenomenon, generally connected to the salinity increase in the Adriatic. These analyses led to the definition of the Mediterranean Oscillation (MO) as a pressure difference between the areas in the Mid North Atlantic and the Southeast Mediterranean. It has been shown that fluctuations of intermediate layer salinity in the middle Adriatic from the period 1947-1995, as a consequence of LIW inflow into the Adriatic, follow year-to-year atmospheric pressure fluctuations. The analysis of atmospheric pressure field and correlation to salinity were performed for the winter (Dec-Mar) data also.