Long-Term Sea Level Changes Along the Lagoon Shores of the Baltic and Black Seas

摘要

We examine the data on the mean annual sea level dynamics for 1875-2005 along the eastern coast of the Baltic Sea (Baltiisk and Kronstadt) and along the northern coast of the Black Sea (Odessa, Sevastopol' and Kerch) which have coastal lagoons. The study revealed a generally positive trend for the period (from 0.7 to 1.8 mm/year at different points), a similarity of changes in the level for separate 30-year-long intervals, and a significant increase in sea level growth rate at the turn of the 20~(th) century (up to 8.6-13.3 mm/year at different points). High values of the correlation coefficient (0.71-0.87) were recorded between the variations in the mean yearly level (with the temporal trend excluded) within the lagoon coasts of the Baltic and Black Seas as well as the absence of a correlation between data series for the two seas. Analysis (after excluding a linear trend from the variation of the values) showed an actual absence of a correlation between mean yearly level variations and North Atlantic atmospheric circulation indices, while the previously recorded correlation was due to a correlation between trend components. It is suggested that the sea level oscillations include only a small component which responds oppositely for the two seas to the resultant influence of the eastward and westward components of the atmospheric circulation. On the basis of the similar absolute values of the linear trend and of the range of long-term fluctuations in mean yearly sea level values in the area of the lagoon coasts of the Baltic and Black Seas, the conclusion is drawn about the similar conditions under which over the course of the last 100 years the coastal lagoons have been evolving in these two, relatively remote, zones of the drainage basin of the Atlantic Ocean.