Long-term series of observations on the glacier of the southern slope of Elbrus manifest the change of two climatic periods in the highlands of the Caucasus. During the first one, relatively cold and snowy period of 1982–1997 with a small positive mass balance, the Garabashi Glacier accumulated a layer of 0.8 m.e. The second period (1998–2017) is characterized by rising summer air temperatures and increasing precipitation in the first decade, and catastrophic melting in 2010–2017. The mass balance of the glacier averaged −0.63 m w.e. yr−1, and in some years it reached −1.00 ÷ −1.50 m w.e. yr−1. In the last ten years, frequency of vast anticyclones covering the southern part of the European part of Russia and the North Caucasus increased. Summer temperatures in the Elbrus region rose to almost the level of the 1950s that was the hottest decade of the XX century. Duration of the summer season on the glaciers increased. Active melting resulted in elevation of the equilibrium line of the Garabashy Glacier by 200 m. In the main part of the glacier alimentation area, i.e. at heights of 3800–4000 m, the large parts of the firn area had disappeared, but open ice of the ablation zone had appeared. The former areas of the "warm" firn zone, where up to 35% of melt water retained within the 20‑meter firn thickness, were replaced by the firn-ice zone, and the ice discharge increased. The glacier alimentation is decreased, and its tongue retreats with increasing velocity. Rocks and entire lava ridges release from ice at different levels of the glacier. The inter-annual variations of the glacier mass balance are controlled by intensity of ablation. In the second period, the correlation coefficient of these values reached 0.97 compared to 0.82 in the first one. In total over 36 years of observations, reduction of the glacier mass during the second period resulted in loss of volume (0.05 km3 or 14%), area (0.51 km2 or 11.4%), and of ice layer (11.4 m).
The concentration of heavy metals (Cr, Ni, Mo, Mn, Pb, Zn, Ag, Cu, Cd, Co, Al, Fe, V) in one of the most powerful glaciation sites in the Caucasus (Mount Elbrus) since the mid-20th century is investigated. To compare the concentrations of heavy metals in the sources of the Baksan River with those in the Garabashi glacier, a stationary point at a level of 4000 m was chosen, where observations of the glacier mass balance are carried out. The number of pit samples depended on the snow accumulation and varied from 7-8 to 18-20 in accordance with the depth of the seasonal snow layer. The concentrations of heavy metals in the ice, snow, and river water samples were determined during the period from 1978 to 2010 at High-mountain Geophysical Institute by the emission spectral analysis. The analysis of samples from 2018-2021 was performed by the atomic absorption method on an MGA-915 spectrometer. Among all categories of the samples taken on the Elbrus slope, the least impurities were found in pure ice on the tongue of the glacier: it contains three times less impurities of Ag, Ni, Mo, Pb: 0.014, 1.15, 0.18, 0.83 µg/L, respectively. In some samples, the metal content is below the detection limit. The concentrations of heavy metals in the seasonal snow pack and river water in the Elbrus region are one-two orders of magnitude lower than maximum permissible concentrations for sanitary water bodies. For the Baksan River basin and the Elbrus glaciation region, there is a slight decrease in the concentrations of heavy metals from the end of the 20th century until the present, with intensive degradation of glaciers.
Atmospheric precipitation is an important factor in the self-purification of the atmosphere from trace impurities of both natural and anthropogenic origin. Microparticles in the atmosphere are effectively removed from it, both with precipitation and in the form of dry precipitation. Snow cover is a natural plate storage of pollutants falling out of the atmosphere in dry form and with precipitation. The study of the chemical composition of microimpurities in solid sediments in the zone of accumulation of glaciers opens up significant opportunities in the study of background monitoring of air pollution.The microstructural analysis and chemical composition of the microparticles of the snow-ice stratum of high-mountain glaciers allows determining the composition of aerosols, the rate of their receipt, genesis, as well as the exact dating of the layers according to the historical time interval.In the paper we present microparticle concentration falling on the glacier surface determined when obvious precipitation (dry fallout) has not been observed. Dry fallout monitoring has been conducted for different elevations of Elbrus Region including its bottom valley and upper level of 4000m a.s.l. The concentration of water-solid insoluble particles in snow samples has been determined using electron and optical microscopes. The results revealed a clear vertical volume and size distribution of microparticles (MP), as well as their modification during the summer and autumn months.The heavy metal (HM) concentrations in snow have been determined using emission spectral analysis.
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