Changes in solar radiation and their influence on temperature trend in Estonia (1955–2007)



[1] On the basis of the data from Tartu-Tõravere Meteorological Station (58°16′N, 26°28′E), changes in solar radiation and temperature in Estonia have been studied for the past half century. Two different periods have become evident in the analyzed time series of solar radiation: a statistically significant decrease in the annual totals of global and direct solar radiation has been detected for the period from 1955 to the beginning of the 1990s, while opposite trends have become evident during more recent years. These changes are in correlation with the changes in the amount of low clouds and in the transparency of cloudless atmosphere (atmospheric aerosol loading). Unlike solar radiation, annual mean temperature has continuously increased during 1955–2007. No time intervals with different slopes have been found in its time series. Because of the relatively short sunshine duration and low Sun elevations, the impact of solar dimming and brightening on the observed warming has turned out to be negligible in the Baltic Sea region.