Ten-day variability of the summer circulation in the North Adriatic

Abstract

Current, temperature and salinity data, collected during the ASCOP experiment that was carried out in the eastern part of the North Adriatic in summer 1989, have been analyzed together with related meteorological and hydrological data. After dividing the current series into three nearly equal subintervals, residual currents have been calculated for each of them. The major feature this exercise revealed was variability at a time scale of about ten days. A similar phenomenon has been observed by Italian researchers in the northeastern part of the Adriatic during several summers.

 It has been shown in the paper that the wind episodes registered during the experiment, although inducing remarkable changes in temperature and salinity records, did not directly generate the observed current variability. The changes in the Po River outflow have also been ruled out as the cause of the observed current reorientation.

Temperature data collected in the area have pointed to stratification as the factor controlling the observed current variations. The stratification itself was influenced by buoyancy fluxes and wind forcing. However, further theoretical and empirical work is needed to establish conclusive evidence and elaborate dynamics of the observed phenomenon.