ИСТИНА

The consequences of global climate change impact require the development of modeling methods for diagnosis and forecasting of negative phenomena associated with the reduction of glaciers. Such tasks require the availability of high-quality in-situ data obtained on the surfaces of mountain glaciers for the longest possible period. In most mountain-glacier regions, including the Great Caucasus, meteorological observations are located in mountain valleys and don’t reflect the climatic features of mountain glaciers. In the Caucasus, the region of Elbrus volcano, is the most studied. Here, on the WGMS reference glaciers Djankuat and Garabashi, regular measurements of meteorological parameters and mass balance are carried out. However, they cover only the ablation zones in summer and the observation data series don’t exceed 3-4 months. In the accumulation zones of the Caucasus glaciers, there are practically no in-situ data on the meteorological regime. In September 2021, a modern meteorological complex was installed on the southern slope of the Elbrus Mountain, in the accumulation zone of the Garabashi glacier (4750 m a.s.l.), and unique automated observations were carried out covering 9 months. Data were obtained on temperature and humidity characteristics, wind speed and direction, snowdrift transport and radiation balance components with a 1-minute time resolution, as well as on the data from acoustic anemometer pulsation measurements. Also in August 2024, similar autonomous meteorological complexes were installed in the ablation zone (3900 m a.s.l.) of the Garabashi and Mikelchiran glaciers on the southern and northern slopes of Elbrus, respectively, for continuous monitoring. Synchronous meteorological observations on glaciers located on different exposures slopes allow to quantitatively assess the differences in crutial factors that determine the mass balance and dynamics of glaciers: all the heat balance components, the rate of snowdrift transport and sublimation of ice crystals during blizzards. Continuous observations of the surface height and temperature inside the snow-ice layer are also carried out, which could be used as a testing site for snow cover models verification. The data series analysis showed that the representative temperature in winter at an altitude of 4700 m a.s.l. on the southern slope of Elbrus is -10℃, the minimum is -36.4℃, and the partial pressure of water vapor doesn’t exceed 3.5 hPa. Blizzards with a transfer intensity of more than 0.1 kg/m2 s are quite common in winter, and the maximum average value of the snowdrift transfer intensity was 0.87 kg/m2·s. The integral snowdrift transport for 9 months of the accumulation season was 105 kg/m2. Such estimates are close to the conditions of East Antarctica, where snowdrift transport intensity values of up to 1.15 kg/m2·s were obtained. In addition, the quality of reanalysis data for high-mountain regions was assessed using the ERA5 reanalysis as an example. It was shown that the ERA5 reanalysis reproduces the values of temperature, wind speed and air humidity in high-mountain conditions quite successfully, but extreme values are underestimated for all quantities.