Changes in snow cover over Northern Eurasia in the last few decades

Abstract

Daily snow depth (SD) and snow cover extent around 820 stations are used toanalyse variations in snow cover characteristics in Northern Eurasia, a region thatencompasses the Russian Federation. These analyses employ nearly five timesmore stations than in the previous studies and temporally span forty years. Arepresentative judgement on the changes of snow depth over most of Russia ispresented here for the first time. The number of days with greater than 50% ofthe near-station territory covered with snow, and the number of days with thesnow depth greater than 1.0 cm, are used to characterize the duration of snowcover (SCD) season. Linear trends of the number of days and snow depth arecalculated for each station from 1966 to 2007. This investigation reveals regionalfeatures in the change of snow cover characteristics. A decrease in the duration ofsnow cover is demonstrated in the northern regions of European Russia and inthe mountainous regions of southern Siberia. An increase in SCD is found inYakutia and in the Far East. In the western half of the Russian Federation, thewinter-averaged SD is shown to increase, with the maximum trends being observedin Northern West Siberia. In contrast, in the mountainous regions of southernSiberia, the maximum SD decreases as the SCD decreases. While both snow covercharacteristics (SCD and SD) play an important role in the hydrological cycle, ecosystemsdynamics and societal wellbeing are quite different roles and the differences in theirsystematic changes (up to differences in the signs of changes) deserve further attention.