Variability of temperature and salinity over the last decade in selected regions of the southern Baltic Sea

Changes in the basic physical properties of selected areas of the Baltic Proper were analysed on the basis of the results of a 12-year series of high-resolution measurements collected during cruises of r/v ‘Oceania’. The high-resolution CTD sections covered three main basins: the Bornholm Basin, Słupsk Furrow and Gdańsk Basin. Positive temperature trends of 0.11 and 0.16°C year−1 were observed in the surface and deep layers respectively. The salinity trend was also positive. The rise in the air temperature has probably caused the increase in surface water temperature, while advection has been of greater significance in the deep layer. The increase in salinity coincides with the more frequent occurrence of small and medium-size inflows through the Danish Straits, even though large inflows are evidently less frequent than used to be the case. The seasonal variability of temperature in the water column was analysed. The phase shift in the seasonal evolution with depth is described. The maximum temperature shift in the waters investigated varies from 32 to 38 days.