The response of the general circulation of the Baltic Sea to climate variability

• Main Authors: Getzlaff, Klaus, Lehmann, Andreas, Harlaß, Jan
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2011
• Subjects: Arctic; North Atlantic
• Online Access: https://oceanrep.geomar.de/id/eprint/13825/; https://oceanrep.geomar.de/id/eprint/13825/1/Newsletter_14_web.pdf

The warming trend for the entire globe is 0.04°C per decade for the period 1850-2005. Furthermore, from around 1980 to present, a specifi c warming period started, with a temperature increase of about 0.17°C per decade, especially on the northern hemisphere. For the Baltic Sea catchment, which is located between maritime temperate and continental sub-Arctic climate zones, an even stronger warming of about 0.4°C per decade was observed since 1980. Changes in the atmospheric conditions cause corresponding changes in the Baltic Sea, not only for temperature and salinity, but also for currents and circulation patterns. The analysis of the winter (DJFM) circulation patterns for the period 1970-2008 reveals changes in the general circulation of the Baltic Sea. While it is diffi cult to clearly link individual winter circulation patterns to one of the four dominant atmospheric climate regimes for the North Atlantic domain, the comparison of mean winter circulation patterns for 20- year periods (1970-1988 and 1989-2008) highlights that for the later 20-year period an intensifi ed cyclonic circulation exists in the central Baltic Sea. This intensifi ed circulation results from stronger westerly and north-westerly winds and is most likely connected to changes in the large-scale atmospheric circulation.