Variations of the Sa and Ssa tides in the Adriatic Sea

Abstract

      This paper deals with the variations of Sa and Ssa tides in the Adriatic Sea calculated from the hourly sea level data collected at four tide gauge stations during the period 1986-1995. The ampli­tudes and phases show a very notable year-to-year variability, with higher values during the peri­od of 1989-1993. Sa amplitudes are on average 20 % higher in the North than in the South Adriatic, while Ssa amplitudes are the same in the entire Adriatic. The Sa phase is between 180° and 230°, but the opposite phase is noticed in 1986 and 1988. The generating forces of the tides include steric effect, atmospheric pressure and evaporation minus precipitation; however interannual changes are primarily the result of air pressure changes. The Sa amplitude as the result of processes other than air pressure is 6.0 cm.