Circulation-related conditions of variability of cloudiness in Poland in the second half of the 20 century

Abstract

The report presents the results of studies concerning variability of the magnitude of the average area cloudiness in Poland in the years 1951-2000, and its association with the characteristics of atmospheric circulation over central Europe. The description of the circulation conditions was made using the average monthly values of atmospheric pressure, pressure gradients, as well as vectors of geostrophic wind, determined with respect to the area contained between the parallels of 45 and 60°N and the meridians of 10 and 30°E. The dependencies were determined with the help of correlation coefficients and the regression equations. Besides, the macro-types of circulation were identified, conducive to the seasonally and annually anomalous cloudiness values. Likewise, the 50-year trends of changes in the circulation and nephological conditions were established.