ИСТИНА

As observations show, the intensity of modern warming in the Arctic zone increases with latitude, but the rate of warming varies across the territory. The maximum temperature increase of 1°C/10 years is observed on the Arctic islands, and the minimum increase of 0.2 °C/10 years in the south of the Russian Arctic territories. The warming rate is higher in spring and autumn than in summer and winter. Warming caused significant changes in the duration of snow cover. In the work, we studied the fluctuations in the snow cover in the Arctic zone of Russia at the beginning of the 21st century in relation to the variability of surface air temperature and precipitation. The MODIS / Terra satellite data were used. They show the share of snow cover on the cell of 5 × 5 km and observational data from meteorological stations. The greatest statistically significant contribution to the interannual variability of constant snow cover period and dates of its destruction are precipitation of the cold period and, to a lesser extent, the date of temperature transition through zero in spring. For the duration of the snow cover occurrence, significant correlation coefficients were found with the dates of the temperature drop below 0 °С and with the number of days of negative temperatures. In the north of the East European Plain, in Western Siberia and in the Far East, stable snow cover in condition of sufficient precipitation forms before the surface air temperatures attain negative values. In cold conditions with less precipitation in Central Siberia, stable snow cover forms after attainment of negative air temperatures. In northwestern Siberia, the formation of a stable snow cover advances the drop in surface temperature below zero due to sufficient precipitation at the beginning of winter. Everywhere the destruction of stable snow cover in spring occurs after the transition of surface air temperature through zero. Changes in the climate characteristics result in that due to decreasing of the solid precipitation in winter time the snow presence duration becomes shorter over the European part of Russia and in the Western Siberia. The shortening in the Middle Siberia is caused by the spring warming. A tendency to increase the duration of snow cover caused by autumn cooling is observed in Chukotka only.