The Effect of Climatic Changes on Vertical Moisture Exchange in Soils

The effect of climatic changes on surface and underground runoff cannot be explained without studying such changes on such processes of moisture transfer in soils as infiltration, evaporation, migration of moisture to the frost front. These processes are components of moisture exchange in soils and almost completely determine the mechanisms of runoff formation and its climatic interconformity. The paper discloses the main links of vertical moisture exchange in soils with environmental factors such as temperature, precipitation, wind speed and water vapor pressure. On the example of the Volga basin, changes in moisture flows in soils over the past decades are considered. Methods. To reveal the patterns of moisture exchange, a physically sound mathematical model of vertical heat-moisture transfer in soils and snow cover was used. Numerical experiments were carried out to assess the impact of all the main weather factors that cause long-term changes in vertical moisture flows in soils for the period 1952-2019. Results. Calculations showed that in the 1970s there were significant changes in soil moisture flows. There was a preferential increase in downstream flows and a decrease in upstream flows, which under certain weather conditions led to an increase in the level of groundwater. In recent decades, the growth of descending soil moisture flows in the river basin. Volga and, accordingly, groundwater levels have slowed down.