THE CHANGES IN RUSSIAN WINTER SNOW ACCUMULATION DURING 1936-83 AND ITS SPATIAL PATTERNS

Winter snow depth observations from 119 Russian stations during the ye ars 1936-83 are selected. These irregularly spaced station data are th en interpolated into 220 regular grids of 2 degrees lat x 5.24 degrees long that cover a region of 50 degrees-70 degrees N, 30 degrees-140 d egrees E. The spatial variation patterns of the annual Russian winter snow accumulation during the period of 1936-83 are identified by using principal components analyses. Statistically significant trends in ma jor snow depth variation patterns are detected. A method is constructe d to estimate the spatial distributions of the total amount of snow de pth change based on the significant trends of component scores during the period of 1936-83. The study found that snow depth has increased o ver most of northern Russia and decreased over most of southern Russia during the study period. Exceptions are found in northern European Ru ssia, where a slight decrease in snow depth has occurred and in southe rn west Siberia where the snow depth has increased. The total amount o f snow depth increase more than compensates for the total amount of de crease in Russia. The most significant snow increase regions are found in the northern Ural Mountains (about 60 degrees-70 degrees N and 50 degrees-70 degrees E) and northern central Siberia (60 degrees-70 degr ees N and 110 degrees 130 degrees E). The most significant snow decrea se is found on the southern Ural Mountains (50 degrees-55 degrees N, 5 5 degrees-65 degrees E). An increase of 4.7% per decade in the snow de pth is estimated in northern Russia (north of 60 degrees N), which is fairly consistent with the amount of snowfall increase estimated in no rthern Canada in previous studies. The total snow depth change in the study region for the period of 1936-83 is estimated to be equivalent t o 43.23 km(3) of water. The study suggests that the winter snow depth increase in polar continents might be a circumpolar phenomena.