On generation mechanisms of intrusive finestructure in the Baltic Sea

Using data from closely spaced CTD profiles taken after the 1993 major infl ow of the North Sea waters, we investigated the characteristics and generat ion mechanisms of finestructure intrusions in the Baltic halocline. Salt fi ngering is nor possible due to the strong prevalence of salinity over tempe rature in density stratification, and diffusive convection has a limited ef fect on thermohaline intrusions in the halocline. Some indirect evidence fo r inertial oscillations as a driving mechanism for the intrusions found. In several occasions, we observed unusual intrusion-like structures crossing isopycnals in such a way that the along-layer density ratio was approximate ly equal to the vertical density ratio. It is shown that these "unusual int rusions" are nor likely to be generated due to the interleaving process, an d several alternate scenarios for their generation are suggested.