On the Frictionless Influence of Planetary Atmospheric Waves on the Adriatic Sea Level

Abstract

The influence of planetary atmospheric waves on the Adriatic sea level is investigated for the year 1976 on the basis of 500 mb surface height and sea level data. Analysis is performed in time and frequency domains. It is found that?in the first approximation?the lower layers of the atmosphere are characterized by barotropic structure in the scope of the mentioned processes, while the equilibrium of sea-elevation gradient with air-pressure gradient is realized in the sea. Accordingly, sea level changes are opposite in phase to the oscillations of a selected isobaric surface; the ratio of their amplitudes is the same as the one between (sea surface) air density and density of the sea. Departures from this simple relationship result from the baroclinic atmospheric disturbances that occasionally influence the sea in the frequency band corresponding to planetary atmospheric waves.