Soil Temperature of Steppe Landscapes in the South of Eastern Siberia and Its Response to Climate Change

Abstract

Soil temperature is an important indicator of climate resources. It characterizes the contemporary functioning of steppe landscapes. The strongest wintery cooling of the entire 3.2-m-thick soil profile is typical for southern Transbaikalia, where seasonal freezing is deep (more than 3 m) and durable. Steppe soils in the south of the Central Siberian Plateau, where seasonal freezing depth varies from 1 to 2.6 m, cool more slightly. The summer warming of soils is almost uniform over the entire study area. Our analysis of the soil temperature amplitude has shown a wider range of its values in Transbaikalia as compared to the south of the Central Siberian Plateau. Amplitude decreases with depth. Its values testify to the smaller continentality of the soil climate in steppe landscapes at the edge of the Central Siberian Plateau relative to southern Transbaikalia. The soil temperature reaction to climate dynamics is analyzed in steps, where series of climate parameters (air temperature, total atmospheric precipitations, and soil temperature at a depth of 40 cm in January and July) are available at meteorological stations for the period of 1985–2020. Means, trends, and correlations of these parameters are calculated. A summer rise in soil temperature following the increase in air temperature is observed at all stations in recent decades. The trend values at some of the meteorological stations reach 0.7–1.5°С per 10-year period. Correlations between the dynamics of summer soil temperatures at the specified meteorological stations are rather high (0.5–0.8). The tendencies and dynamics of winter temperatures are more variable. The nonuniform snow cover of the area contributes to factors affecting the winter temperature regime.