Long-term changes in hydrothermal conditions in Siberia
Authors/Creators
- 1. Institute of Monitoring of Climatic and Ecological Systems SB RAS (IMCES SB RAS), V.B.Sochava Institute of Geography SB RAS, Irkutsk, Russia
- 2. Institute of Monitoring of Climatic and Ecological Systems SB RAS (IMCES SB RAS)
Description
The territory of South Siberia includes different landscape zones. For correct comparison of occurring
hydrothermal changes it is necessary to use, as it was shown in our works and works of other authors,
normalized indices, which include the Ped Aridity Index (S) and standardized index of precipitation and
evaporation SPEI. Data on air temperature and precipitation totals at 134 weather stations and Era5 reanalysis
grid nodes for 1950-2020 were used as input information for calculating the indices. Changes in hydrothermal
conditions within the territory are characterized as follows. In May, aridity increases in most of the territory,
except for the mountainous regions of Transbaikalia. In June, moisture increases in the central areas of Western
Siberia, while the south of Eastern Siberia becomes more arid. In July, the contrasts increase, with S trends
across the territory varying from -1.0 to +1.4 units/10 years. In August and September, there is a latitudinal
distribution of trends - from positive in the south to negative in the north of Siberia. However, not all trends are
statistically significant. There is no direct linear dependence of hydrothermal conditions on large-scale circulation
processes for most weather stations located in southern Siberia. This does not mean its complete absence,
but only indicates a more complex nature of the relationships. The greatest number of statistically significant
correlation coefficients (for each month at 50-60 weather stations out of 134) was obtained for the SCAND indices,
AO and various Atlantic fluctuations.