Trends in changes in climate variables and their influence on the soil temperature regime in the Arctic zone of Western Siberia
E.V. Kharyutkina1,2, E.I. Moraru1, S.V. Loginov1
1Institute of Monitoring of Climatic and Ecological Systems of the Siberian Branch of the Russian Academy of Sciences, Tomsk, Russia
2National Research Tomsk State University, Tomsk, Russia
Keywords: air temperature, soil temperature at depth, snow depth, atmospheric precipitation, ERA5 reanalysis, CMIP6, permafrost, climatic projection, Arctic
Abstract
In the context of accelerated warming in the Arctic, the study of changes in permafrost zone characteristics is a question of high interest. The paper analyzes current and future changes in climate variables (surface air temperature, soil temperature at depth, precipitation, and snow cover depth) in the Arctic part of Western Siberia based on the ERA5 reanalysis and CMIP6 modeling data. The contribution of climate variables to the variability of the soil temperature at depth is estimated in three climate scenarios (Historical, SSP2-4.5, SSP5-8.5). The surface air temperature, soil temperature at depth, and precipitation are predicted to increase in all seasons by the end of the 21st century, while the snow cover depth will decrease. This will result in an increase in the area and depth of seasonal thawing layer and a northward shift of the southern boundary of permafrost zone. According to the SSP5-8.5 scenario, the annual average soil temperature zero isotherm will be located at a depth of ~ 6 m at latitude of 70° N (the territory between the Gulf of Ob and the Lower Yenisei Upland). Currently, the influence of the climate variables on changes in the soil temperature at depth is maximal in summer (due to air temperature) and autumn (due to snow cover) with their maximum contribution in October (up to 60% at a depth of 1 m). According to the SSP5-8.5 scenario, a decrease in the contribution of climate variables in summer and its increase in November are expected. By the end of the 21st century, the predominant contribution to the variability of the permafrost zone characteristics will belong to summer precipitation. The results can be used in studies and simulation of changes in the permafrost zone characteristics.
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