Precipitation changes on the Polish coast of the Baltic Sea (1954–2003) due to changes in intensity of westerlies over Europe

• Published in: Climate research Vol. 48; no. 1; pp. 23 - 29
• Main Author: Swiatek, M
• Format: Journal Article
• Language: English
• Published: Inter-Research 19-07-2011
• Subjects: Advection; Atmospheric circulation; Climate change; Climate models; Coasts; Marine; Meteorology; Precipitation; Seas; Seasons; Weather stations; ANE, Europe; ANE, Poland, Pomorskie, Gdynia; ANE, Baltic Sea
• ISSN: 0936-577X; 1616-1572
• DOI: 10.3354/cr00904

The present study investigated changes in precipitation totals, frequency of days with precipitation, and relationships between precipitation totals in individual seasons at several weather stations on the Polish coast of the Baltic Sea. From 1954 to 2003, precipitation totals were almost invariant, except for a significant positive trend in March precipitation totals in Szczecin, Koszalin, 1eba, and Elbląg. Much more extensive were the changes in the frequency of wet days. Time-series analysis of the precipitation frequency demonstrated an increasing annual wet-day total on the eastern part of the coast (Hel, Gdynia, and Elbląg). The increase occurred at the highest rate in Elbląg. A significant upward trend was observed at almost all weather stations in June, and also in Elbląg in January, March, and October, and in Koszalin in February. Atmospheric circulation is a major factor influencing both short- and long-term fluctuations in precipitation. Therefore, we also analysed the links between changes in the frequency of wet days and changes in large-scale atmospheric circulation (the intensity of westerlies in particular). These relationships were explored by comparing the frequency of precipitation events in periods with differing intensity of westerlies. The present study demonstrated that the direction of air-mass advections have a stronger effect on the number of days with precipitation than on precipitations totals. More intense western advection causes more frequent precipitation, especially in the eastern part of the study area.