Hydrothermal conditions of South Eastern Siberia under the ongoing warming

A great increase in air temperature has been observed since 1976. Siberia is a region with most severe ongoing climate change. To monitor the extreme weather events is important. To evaluate moisture conditions we used the D.A. Ped index (Si). Monthly air temperature and precipitation data from 19 weather stations of South Eastern Siberia (50-60° N 90-120° E) were used for the index calculation during the vegetation period. During 1976-2010 the number of droughts in the study region was more than the number of excessive moisture periods. The maximal statistically significant trend (0.4-0.6 per 10 years) in Eastern Siberia was observed in May. The characteristics of the winter-spring period preceding the vegetation season were analyzed. Significant positive trends exist in the study area for the May temperature (0.5-0.9 °C per 10 years) and the May sum of positive temperatures (14-28 °C per 10 years). There are tendencies to increase the number of days with temperatures above zero in March (1-3 days per 10 years) and the sum of positive temperatures in April (5-16 °C per 10 years). The stable transition of air temperature over 0 °C shifts into early dates by 1-7 days every 10 years.