Changes in Hydrothermal Conditions in Southern Siberia in 1950–2020 and Their Relation to Large-scale Circulation Processes

Abstract

The paper presents the dynamics of the hydrothermal coefficients characterizing agroclimatic resources on the territory of Siberia within the coordinates of 50°–65° N, 60°–120° E during modern climate change. The intensity, frequency, and duration of adverse weather phenomena for agriculture (the atmospheric droughts and moisture excess conditions) are analyzed. The Ped’ drought index (\(S\)) and the standardized precipitation evapotranspiration index (SPEI) calculated from the data of 134 weather stations and the ERA5 reanalysis are used as an indicator. In Eastern Siberia and in the west of the analyzed territory, there is an increase in aridity (a trend is 0.2–0.5 per decade). Northern regions of Kazakhstan, the Sayan Mountains, and the West Siberian Plain were characterized by a relative stability of hydrothermal conditions in 1950–2020 (statistically significant changes are not revealed). A direct linear dependence of hydrothermal conditions on large-scale circulation processes have been not detected for most cases. The greatest number of statistically significant correlation coefficients has been obtained for the drought index \(S\) and the SCAND (Scandinavia teleconnection pattern) index.