[M-IS01] ENVIRONMENTAL, SOCIO-ECONOMIC, AND CLIMATIC CHANGES IN NORTHERN EURASIA

[MIS01-P18] Long-term changes in hydrothermal conditions in the constituent entities of the Siberian Federal District

*Anna Ryazanova¹、Nadezhda Voropay^1,2 (1.Institute of Monitoring of Climatic and Ecological Systems of the Siberian Branch of the Russian Academy of Sciences、2.V.B.Sochava Institute of Geography of the Siberian Branch of the Russian Academy of Sciences, Irkutsk, Russia)

キーワード：Selyaninov hydrothermal coefficient , Siberian Federal District , Excessive Humidity Zone

The relationship between heat and moisture determines the zonal types of landscapes and, consequently, the main features of the nature of geographical zones. To date, the conditions of moisture and aridity in the European territory of Russia have been studied quite well. In the Asian Territory of Russia after the 60s of the 20th century, such work was carried out only in certain regions. The territory of this study is the Siberian Federal District (SFD. The information basis of the work is meteorological parameters of high spatial resolution (ERA5 reanalysis). At the first stage of the work, using previously developed software modules, the dates of transition of air temperature through certain limits, the Selyaninov hydrothermal coefficient (HTC) within the period 1950-2020 were calculated, maps of the main climatic indicators were constructed, and trends in their changes were identified. The main climatic indicators include the average annual temperature, the annual amount of precipitation, HTC, the duration of the growing season, the duration of the frost-free period. The average long-term annual air temperature has an almost latitudinal distribution; a zonation is introduced into the picture by mountain ranges. Trends in air temperature changes in the SFD are consistent with changes occurring in the Asian territory of Russia and in the Northern Hemisphere as a whole. Warming in the northern regions is an order of magnitude more intense than in the southern ones. Trends in the series of dates of temperature transition through 0°C indicate an increase in the period with positive air temperatures. The dates of transition of air temperature are shifted to earlier dates in spring. The distribution of annual amounts of atmospheric precipitation follows the outline of the relief shape. The maximum (more than 1500 mm) is observed in the mountains of Southern Siberia, the minimum (up to 300 mm) in steppe areas. Trends in changes in annual amounts of atmospheric precipitation are in most cases not statistically significant. The results obtained provide a reliable idea of the distribution features of long-term trends in changes in hydrothermal characteristics, and, therefore, describe the conditions of aridity/waterlogging in the SFD against the backdrop of global climate change. During the historical period, statistically significant positive trends in air temperature and mostly insignificant trends for precipitation are observed in the territory of the SFD. HTC trends during the observation period are statistically significant (negative) only in the Irkutsk region and in the eastern of the Krasnoyarsk region. Statistically significant change in the dates of transition of average daily air temperatures through 0, +5, +10 °C in the spring in most parts of the territory to earlier dates and a change in the dates of transition through the same limits in the fall in some areas (statistically significant trends are noted in a much smaller area) led to an almost universal statistically significant increase in the duration of periods with average air temperatures above 0, +5, +10 °C, respectively. According to calculations of climate projections according to CMIP scenarios (SSP1, SSP5), most of the SFD, both in the past and in the coming decades, will be located in the Excessive Humidity Zone (1.3 < HTC < 2.0). The shift of the boundaries of all zones in the next 30 years, according to calculated data, can occur in different directions (mainly from south to north). This displacement will generally be no more than 50-100 km, in rare cases up to 200 km. At the same time, on the territory of the district there will be a slight increase in areas with hydrothermal conditions characterizing steppe and forest-steppe landscapes. Over most of the territory, the choice of scenario does not significantly affect the movement of the boundaries of zones with different moisture conditions. Differences in changes generally do not exceed 20-30 kilometers.