Snow depth in eastern Europe in relation to circulation patterns

Abstract

AbstractRotated principal components of the 500 hPa geopotential heights in the Euro-Atlantic sector are used as indicators of circulation pattern intensity. Daily snow-cover depth data for the years 1951–95 from 71 eastern European stations are examined. Maps of linear correlation coefficient between monthly change in snow depth and rotated principal components are presented. The positive and negative extremes of each circulation pattern are analyzed, and positive and negative snow-depth signals indicated. A daily analysis of relationships between snow depth and circulation pattern is performed for three locations. The strongest impact of the atmospheric circulation on changes in snow depth is observed in the south and west of the study area, where the eastern European (EE) and central European circulation patterns are found to have the greatest impact. The North Atlantic Oscillation (NAO) impact on the snow depth in eastern Europe is limited to the beginning and the end of winter. Snow cover has low variability in northeastern Europe (where the Scandinavian (SC) pattern is of greatest importance) and low sensitivity to change in the atmospheric circulation. The decrease in snow-cover depth observed in spring is related to the NAO, SC and EE patterns, the latter being important for snow-cover depth fluctuations over northeastern Europe in April.