Abrupt Increases in Soil Temperatures following Increased Precipitation in a Permafrost Region, Central Lena River Basin, Russia

Marked increases in active-layer and upper permafrost temperatures occurred in the central Lena River basin in association with abrupt increases in active-layer soil moisture following the summer of 2005. The positive trend in soil temperature-moisture relations was observed at monitoring sites in the Yakutsk area, regardless of vegetation and soil type. The increase in soil temperature appears to have started in response to the large amounts of snow that accumulated in the winter of 2004. Abnormally high pre-winter rainfall and snowfall in the following three years accelerated soil warming through the effects of greater latent heat of freezing and insulation from atmospheric cooling in winter. The consecutive positive anomalies of snow depth and rainfall, which occurred widely in the central and southern Lena River basin during this three-year period, increased soil moisture and appear to have altered the active-layer thermal properties, which likely induced widespread wan-ning of the surface layer of permafrost in this region. Copyright (C) 2009 John Wiley & Sons, Ltd.