14:00 〜 14:15
[MIS01-12] Wind speed changes in Eastern Europe with focus on Belarus and their possible causes
キーワード：Eastern Europe, Belarus, wind speed, decreasing trends
In recent decades, lower than average wind speeds at the airports (i.e., at open to wind movement locations) have been more frequent in Northwestern and Central Europe. The causes of such anomalies are associated with blocking anticyclones over the northeastern Atlantic and Greenland. In such cases, the large high-pressure system over Scandinavia reduces the normal zonal air transport, and the wind speed over Northern Europe is below normal. In addition, a decrease in wind speed is observed in Eastern Europe in Latvia, Belarus, Ukraine, and European part of Russia. At the same time there is an increase in the frequency of squalls and tornadoes in Poland and Ukraine.
Belarus is centered in Eastern Europe with main location on the western edge of the Great East European Plain. The country represents well climatic and environmental changes in the macro region. There is a gradual decrease in wind speed across Belarus over the past 50 years. The average annual wind speed of 2 - 4 m s−1 dominated in the country for the period of 1950-2010. The wind speeds up to 3 m s−1 are typical for 70% of the annual time. Declining average annual wind speed has ranged from 3.6 to 2.9 m s−1 throughout all months of the year since 1970th. The decrease in average wind speed occurs most significantly in the north of the country and amounts to 0.9 - 1.2 m s−1 in winter and 0.6 - 0.7 m s−1 in summer. Along with this, similar changes occurred in maximum wind speed. The wind gusts decreased by 1.2 m s−1 in the central and southern regions of the country.
In summer wind gusts have increased by 1-3 m s−1 over the past 30 years at most stations in Belarus. Moreover, since 2010 we found increase in annual wind speed by 0.1 - 1.1 m s−1 over a half of Belarus.
Recent changes in wind speed connected with transformation of atmospheric circulation in the Atlantic-European domain. The main indicator of regional climate change over Europe is the North Atlantic Oscillation (NAO). In 1960–1990, the prevailing positive NAO phase defined the lower than normal pressure gradient between the Azores High and the Icelandic Low and winds were weaker than usual. Since the mid-1990s, the intensity of meridional circulation associated with the Scandinavian Pattern (SCAND) has been increasing. With positive SCAND and negative NAO indices, the long wave amplitudes increase and pressure gradient growth cause rising of wind speed.
Belarus is centered in Eastern Europe with main location on the western edge of the Great East European Plain. The country represents well climatic and environmental changes in the macro region. There is a gradual decrease in wind speed across Belarus over the past 50 years. The average annual wind speed of 2 - 4 m s−1 dominated in the country for the period of 1950-2010. The wind speeds up to 3 m s−1 are typical for 70% of the annual time. Declining average annual wind speed has ranged from 3.6 to 2.9 m s−1 throughout all months of the year since 1970th. The decrease in average wind speed occurs most significantly in the north of the country and amounts to 0.9 - 1.2 m s−1 in winter and 0.6 - 0.7 m s−1 in summer. Along with this, similar changes occurred in maximum wind speed. The wind gusts decreased by 1.2 m s−1 in the central and southern regions of the country.
In summer wind gusts have increased by 1-3 m s−1 over the past 30 years at most stations in Belarus. Moreover, since 2010 we found increase in annual wind speed by 0.1 - 1.1 m s−1 over a half of Belarus.
Recent changes in wind speed connected with transformation of atmospheric circulation in the Atlantic-European domain. The main indicator of regional climate change over Europe is the North Atlantic Oscillation (NAO). In 1960–1990, the prevailing positive NAO phase defined the lower than normal pressure gradient between the Azores High and the Icelandic Low and winds were weaker than usual. Since the mid-1990s, the intensity of meridional circulation associated with the Scandinavian Pattern (SCAND) has been increasing. With positive SCAND and negative NAO indices, the long wave amplitudes increase and pressure gradient growth cause rising of wind speed.