The Snow Depth in Forests and Fields on Lowlands of Russia under the Current Climate Conditions

Received August 11, 2023; revised August 27, 2023; accepted October 2, 2023Average values of maximum snow depths (MaxSD) estimated separately under conditions of forests and fields on lowlands of Russia were compared during the past 29 years. It was found that MaxSD in the fields for the current climatic period 1991–2020 increased by 5% compared to the period 1966–1990 and decreased by 8% in the forests. For the periods 1966–1990, 1981–2010, and 1991–2020, the ratio of MaxSD in a forest to similar one in a field (which we refer to as the snow survey coefficient) has been constantly decreasing. The snow survey coefficients for these periods were equal to 1.24; 1.12 and 1.08, respectively. In 1991–2020, the greatest values of this ratio were obtained in the northeast of the European part of the territory of Russia (ETR) and in the south of Western Siberia, where the maximum thickness of snow cover in the forest was found to be significantly higher than in the field. The lowest values were observed in some areas of the ETR center as well as in south-east and south-west, and in the south of Eastern Siberia. Here, for the periods 2001–2010 and 2011–2020, the values of the snow survey coefficients were estimated as 1.07 and 1.03 respectively. The coefficient for 1991–2020 decreased, on average, by 12% compared to 1966–1990. The maximum decrease in this ratio – by 15–25% – occurred in the south-west of Eastern Siberia and in a larger part of the ETR in the south. In 2011–2020, the MaxSD values increased in forests in the south-east of the ETR by 5–15%, and decreased in the south-west and the west of the ETR by 15–25% compared to 1966–1990. At the same time in fields, the MaxSD increased by 15–30% in the east of the ETR and the south of Siberia and decreased in the center and south-west of the ETR by 10–15%. The average value of the MaxSD in the field for the period 2011–2020 increased by 6% compared to 1966–1990 and decreased in the forest by 10%. Relative to other periods, the greatest increase in MaxSD was observed in 2001–2010. In the period 2011–2020, the MaxSD both in the forest and in the field mainly decreased relative to the period 2001–2010. In the current climatic period (1991–2020), the tendency for equalization of the MaxSD in forests and fields has been confirmed.