Evaporation over the Baltic Sea as an example of a semi-enclosed sea

• Main Authors: Bumke, Karl, Karger, Uwe, Hasse, Lutz, Niekamp, Klauspeter
• Format: Article in Journal/Newspaper
• Language: English
• Published: Deutsche Meteorologische Gesellschaft 1998
• Subjects: Sea ice
• Online Access: https://oceanrep.geomar.de/id/eprint/3770/; https://oceanrep.geomar.de/id/eprint/3770/1/Bumke.1998.pdf

Evaporation is a major term in the energy and water cycle of the Baltic Sea. Wide areas of a semienclosed sea like the Baltic Sea belong to the coastal zone, which is a transition zone from the different roughnesses and thermal properties of the open sea and the land surfaces. This causes that wind speeds in coastal areas are generally lower than over the open sea for the same geostrophic wind speeds somewhat dependent on the wind direction relative to the coast. Furthermore the evaporation is hampered by ice, which covers parts of the Baltic Sea during winter time and is more prevalent near the coast. Sea ice and the influence of the coast on the wind speed reduce evaporation by up to about 7 to 8% each. The resulting evaporation is of the same order as previous estimates and shows similar spatial and temporal patterns, but uncertainties remain. It is shown that these depend mainly on the boundary layer parameterization used to calculate the evaporation.