What drives thermohaline intrusions in the Baltic Sea?

Using data from closely spaced CTD profiles taken after the 1993 major infl ow of North Sea water, we investigate the characteristics and generation me chanisms of finestructure intrusions in the Baltic halocline. Due to the st rong prevalence of salinity over temperature in density stratification, the salt fingering is not possible, and diffusive convection has a limited eff ect on thermohaline intrusions in the halocline. Some evidence for inertial oscillations as a driving mechanism for the intrusions is found. In severa l occasions, we observed odd intrusion-like structures crossing isopycnals in such a way that the along-layer density ratio is approximately equal to the vertical density ratio. We show that these 'odd intrusions' are not lik ely to be generated from the interleaving process, and several alternate sc enarios for their generation are suggested. (C) 1999 Elsevier Science B.V. All rights reserved.