Regional distributed trends of sea ice volume in the Baltic Sea for the 30‑year period 1982 to 2019

Abstract

Since more than 100 years, winters in the Baltic Sea have been classified according to their strength and have been compared to each other. In the beginning, the winter strength was only related to the ice coverage along the coasts. However, since the 1980s, also the ice thickness was observed consistently and has therefore been included into the classification scheme. Owing to the international cooperation between the European ice services, we have all the needed information about the winter strength, sea ice coverage, distribution and mass for the entire Baltic Sea available. Thus, we have been able to compute changes in the sea ice conditions for this area covering the last decades and to compare them with changes in the air and sea surface temperatures. For the first time, we show the distribution of the mean accumulated sea ice concentration and sea ice volume as well as its trends for the Baltic Sea. Consistently data reveal a decreasing amount of sea ice that is produced over a winter season for nearly all the sections of the Baltic Sea. The reduced sea ice production correlates generally well with the increase in air and sea surface temperatures over winter months.

Keywords

• sea ice
• sea ice volume
• baltic sea
• climate change
• sea surface temperature