Role of eddies and intrusions in the exchange processes in the Baltic halocline

Intrusions observed in the regions of intense mesoscale eddies of the Baltic Sea are studied. The study is based on the data of the closely spaced CTD profilings performed in the Eastern Gotland Basin after the major inflow of 1993. The results obtained supplement the interleaving analysis presented in [6]. Special attention is focused on the description of the intrusions in the intrahalocline cyclonic eddy that was formed during the inflow. A T, S-analysis of the water structure in mesoscale eddies and beyond them revealed the following features: (a) a substantial difference between the T, S indices in cyclonic and anticyclonic eddies, and (b) a gradual decrease in the salinity of the modified North Sea waters is observed during their propagation into the basin. A phenomenological description of the exchange and mixing processes in the Baltic halocline based on the results of numerical simulation of mesoscale eddies formed during the inflow event and an empirical analysis of the interleaving are suggested.