The analysis of the dependence of characteristics elements of snow on orography on the northeastern slope of the Greater Caucasus

Problem definition. Currently observed global warming is manifesting its effects, as in all regions, on the northeastern slope of the Greater Caucasus. Specifically, the increase in air temperature has caused changes in the elements of the snow cover in the area. The spatial-temporal distribution of snow cover elements, snow cover formation and melting dates, and changes in snow-covered days have been analyzed in the study area. Formulation of the purpose. The research was conducted to determine the variation of snow cover elements depending on orography on the northeastern slope of the Greater Caucasus. Research methods. During the analysis, stationary data on snow cover depth collected from 1964 to 2018 at the Khachmaz, Quba, Khaltan, Altiaghach, Giriz, and Khinalig hydrometeorological stations, as well as snow survey route data for the Gusarchay basin from 1986 to 2019, were used. The research was conducted using comparative and mathematical-statistical methods, along with the StokStat software. Here, the relationship between absolute elevation and snow cover duration was assessed, and it was determined that the number of snow-covered days exhibits greater persistence with increasing altitude. The main material. The analysis determined that on the northeastern slope of the Greater Caucasus, in the period after 1990, while the height of the snow cover increased with rising air temperature, its density decreased. Furthermore, the formation and melting dates of the snow cover underwent variability compared to earlier years (before 1990). This process, as in all areas in recent years, is related to the increase in air temperature and changes in the zero isotherm in the study area. Conclusions. The analysis established that in the upper zones, the passage of the zero isotherm is observed 15-20 days after the average snow cover formation date. In spring, it was determined that snow begins to melt 25-30 days after the temperature crosses zero degrees. On the northeastern slope above 1500 m, the average ten-day snow height varies between 10-25 cm, the maximum height between 15-30 cm, and the extreme height between 30-100 cm. The change in snow line elevation occurs intensively during winter, which is related to periodic temperature rises, with maximum snow height occurring in late February and early March. The research results can be used for water resource assessment, water management planning, and developing specific measures considering the impact of climate change on water resources.