LONG-TERM VARIATIONS IN THE MEDITERRANEAN-SEA LEVEL CALCULATED BY SPECTRAL-ANALYSIS

The aim of this paper is to investigate long-period climatic variation s in the Mediterranean sea level, as well as some meteorological param eters and the influence of atmospheric forcing on sea-level fluctuatio ns. Data for the annual mean sea level at seven stations (Trieste, Gen oa, Marseilles, Alicante, Oran, La Goulette and Sfax), located in the Western Mediterranean, together with mean air pressure and temperature data for Zagreb, have been spectrally analysed. Various peaks in the power, coherence and phase spectra have been detected. The period of a bout 5.1 years corresponds to the quasi-meridional fluctuation in the paths of Atlantic cyclones. The period of about 2.7 years may be excit ed by variations of currents and sea-surface temperature in the North Atlantic. Peaks at periods of 3.0 and 3.5 years show oscillations of s econdary cyclones over the Gulf of Genoa bay and the Adriatic Sea. A q uasi-biennial oscillation has been detected with a period of 2.15 to 2 .25 years. Enlarged amounts of energies at 7.5 to 8 and 11.2 years may correspond to the polar tide and solar cycle oscillation, respectivel y.