Earth’s Cryosphere, 2009, Vol. XIII, No. 1, p. 17-23

RELATION BETWEEN SOIL TEMPERATURE, FREEZING INDEX AND SNOW DEPTH IN YAKUTIA AT THE END OF THE 20TH CENTURY

I.S. Vasiliev

Melnikov Permafrost Institute SB RAS, 677010, Yakutsk, Merzlotnaya str., 1, Russia, konstantinov@mpi.ysn.ru

This report presents an analysis of the relationships between the mean annual soil temperature at a depth of 1.6 m, the air freezing index and the snow depth (based on data of 40 weather stations in Yakutia). These relationships are discussed for the regional groups marked out according to the orientation of linear trends of soil temperature. In the high-latitude lowland regions with a negative trend, a decrease in mean annual soil temperature on the background of stable freezing index can be caused by the long-term bedding of snow cover (retarding the soil warming-up after the occurrence of positive air temperatures) rather than by the consolidation of snow cover with the increased thickness. In the regions with a positive trend, an increase in mean annual soil temperature is caused by the weakening of the Asian anticyclone in winter. In the mountainous regions, soil temperature is determined by local temperature-controlling factors; it decreases in cold landscapes and increases in warm landscapes.

Key words: Mean annual soil temperature, freezing index, snow depth, trend.

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