Lëd i sneg

Received July 28, 2023; revised September 2, 2023; accepted October 2, 2023

A study of the isotope signature of glacial ice in the Western Elbrus Plateau (the Caucasus) was made on the basis of five ice cores obtained in different years with high resolution. It was shown that the isotopic characteristics of ice are associated with the processes of accumulation and wind scouring of snow. Three ice cores were obtained in 2013 (C–1, C–2 and C–3), one in 2017 (C–4) and one more in 2018 (C–5). Core sampling was performed with a resolution of 5 cm. Isotopic analysis was done at the CERL laboratory (AARI) using a Picarro L2130-i isotope analyzer, the accuracy was 0.06‰ for δ¹⁸О and 0.30‰ for δ²Н. The values of δ¹⁸О and δ²Н of the ice of the Western Plateau generally vary from –5 to –30‰ and from –18.7 to –225.8‰, respectively, with well-defined seasonality. Comparison of the isotope record for all cores showed that the differences in accumulation for individual seasons reach 0.3 m w. eq., differences in accumulation for individual seasons averaged over 5 years is approximately 0.2 m w.eq. The absolute differences in the average seasonal values of δ¹⁸O associated with wind scouring and spatial redistribution of snow (deposition noise), averaged over 5 years, reached 1.38‰. The irregularity of precipitation amount within the season and errors in core dating are an additional contribution to non-climate variance (noise of definition). The absolute difference in the average seasonal values of δ¹⁸О associated with this type of noise averaged over 5 years is 1.7‰. Thus, the total uncertainty for two different types of noise can be estimated at 2.2‰, which is about 20% of the annual seasonal amplitude of δ¹⁸O values of the glacier ice in the Western Plateau (the average difference between the δ¹⁸O values of warm and cold seasons is ~10–11‰). One of the problems of linking the isotope record to the annual temperature record at the weather station was solved by using ammonium concentrations for dating the C-1 ice core and calculating the “ideal” annual variation of δ¹⁸O values by a cosine function of the annual amplitude. Using ammonium ion (\({\text{NH}}_{4}^{ + }\)) concentration each annual layer in C-1 ice core was divided into two parts associated to snow deposition in winter and in summer. It also showed δ¹⁸O values associated to change of seasons. The calculation of the cosine function showed the simplified δ¹⁸O values for each month of a particular year, due to which the δ¹⁸O values of the season boundaries in the ice core were linked to calendar months. This assimilation allowed us to compare the obtained average seasonal values of δ¹⁸О from the core with instrumental observations at the Klukhorskiy Pass meteorological station. The δ¹⁸O values of winter seasons have a weak relationship with surface temperatures, not only due to wind erosion, but also due to the high interannual variability of snow accumulation. At the same time, the average δ¹⁸O values of the warm seasons are significantly positive correlated with surface temperature (r = 0.7, p = 0.1), so ice core δ¹⁸O records can be used as a temperature proxy of the warm period.

Received June 29, 2023; revised August 28, 2023; accepted October 2, 2023

Stable isotopes investigation was carried out in the territory of the Yuzhno-Chuya Ridge (Central Altai) during the ablation season of 2022. Samples were taken to determine the contribution of meltwater and precipitation to feeding of water bodies. The main research objects are Nekrasov glacier – Tamozennoye Lake system and Taldura River. In the basin of Lake Tamozennoye, the average ice δ¹⁸O of the Nekrasov glacier (‒17.3%) was obtained. Based on the isotopic composition of ice and precipitation, it was estimated that in the stream flowing into Lake Customs, the contribution of glacier meltwater varies from 28 to 67%, on average 54%. For a stream flowing out of a lake, the proportion of meltwater is higher: 48–72, 61% on average. First of all, meltwater enters the lake by filtration through the moraine, and not by surface runoff. Along the Taldura River, δ¹⁸O does not change significantly (δ¹⁸O –16.58 … –16.84%) for 38 km before the Taldura River confluence into the Chagan River. This indicates the complete predominance of glacier meltwater in the river feeding in the middle of the ablation season. Repeated sampling of water from the Taldura River 5 km from the edge of the glacier showed, that the effect of precipitation can be traced in the isotopic composition of river water, but it does not exceed 20%.

Received June 9, 2023; revised September15, 2023; accepted October 2, 2023

We present an analysis of the equilibrium line altitude (ELA) on the Bellingshausen Ice Dome on King George Island (Waterloo), Antarctica, derived only from ground-based glaciological surveys for the period 2007–2012 and 2014–2023. A good relationship was found between ELA and mean summer air temperature (XII-II months) with a coefficient of determination of about 0.8. Assuming the stability of this relation in the past, the changes in the ELA during the entire period of observations at Bellingshausen weather station (from 1968) were reconstructed. Since negative ELA values were obtained for some years, which is physically impossible, they were artificially adjusted to sea level. A good correlation of air temperature between the Bellingshausen and Deception Island weather stations allowed extending the reconstruction of ELA for a longer period (from 1947).

By cleaning up the strong interannual fluctuations in ELA using five-year moving averages, two complete periods of ELA change (from minimum to minimum) were identified for approximately 20 years (1947–1968) and 45 years (1968–2013). From 2014 to present time, the third period has been continuing. At the apogee of each period, the ELA was higher than the Bellingshausen Ice Dome height, which indicates that in these years the ice dome completely lost accumulation area. For the Bellingshausen and Warsaw ice domes, a pattern of higher ELA position on the western and southern slopes compared to the eastern slopes was revealed, which is probably applicable to the entire King George Island.

Since the ELA variations on King George Island are generally synchronous with its variations on Livingston Island, the reconstructed ELA on the Bellingshausen Ice Dome can probably be useful for reconstructing the glaciation history of the South Shetland Islands.

Received August 11, 2023; revised August 27, 2023; accepted October 2, 2023

Average 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.

Received December 27,, 2022; revised August 10, 2023; accepted October 2, 2023

Geophysical observations of the structure of glacial-permafrost rock formations (hereinafter referred to as GPRF), common in the Central Altai in the valleys of the Chuya, Dzhelo, Elangash and Akkol rivers, were carried out by way of electrical resistivity tomography using the multi-electrode electro-prospecting station “Skala-48”. The main objective of the research was to identify the features of the internal structure of GPRF basing on the data of electrical sounding and aerial photography. The application of the geophysical method made it possible to localize rock-ice cores within the GPRF. Analysis of the geoelectrical cross-sections allowed finding that the rock-ice cores were characterized by high values of specific electrical resistance (SER) – from 10 to 100 kOhm ⋅ m and more. The depths of occurrence of rock-ice material on the geoelectrical sections varied from 2 to 10 m, on the average. Using the data of the aerial photography carried out above the studied areas, three-dimensional geoelectric models and maps of the distribution of SER were built for different depths. When analyzing the three-dimensional model of the GPRF, it is clearly noticeable that the features of the nature of the SER distribution reflects the inhomogeneous distribution of ice within the rock-ice core of the GPRF. As a result of our studies performed by the method of electrical tomography and interpretation of a three-dimensional geoelectric model, it was estimated that thicknesses of the rock-ice material varied from 7 to 32 m, thawing niches were revealed and localized, and the potential volume of the rock-ice core was determined. Thus, the above mentioned geophysical and geomorphological studies in that the features of the internal structure of GPRF in key areas have been established. For each GPRF, the thicknesses, resistivity, and depth of occurrence of rock-ice cores were determined, and the dependence of the morphological structure of the GPRF surface on internal structure of them was analyzed. A preliminary assessment of water reserves in individual GPRF had also been made.

Received January 25, 2023; revised July 6, 2023; accepted October 2, 2023

The Kungur Ice Cave is visited by thousands of tourists every year, so the question of anthropogenic influence on changing its state is acute. Snow and ice formations are the main attraction of the cave. From the moment of discovery and improvement of the cave, the thickness of glaciation began to depend not only on natural, but also on technical and anthropogenic conditions. First, this is a change in the temperature of the outside air, the annual rise of underground and surface waters (the Sylva River), the construction of inlet and outlet tunnels, artificial ventilation, and the number of tourists. To assess the impact of the flow of tourists on the microclimatic characteristics of the Cave, the staff of the Kungur Stationary Laboratory conducted research during the period of maximum anthropogenic load in the summer of 2022. The data analyzed in this article made it possible to clarify that the existing tourist load has an insignificant impact on the microclimate of the Cave. After the passage of each group of tourists, the air temperature in the grottoes slightly increases (by a maximum of 0.1–0.2°C) but is restored during the daytime within 4–12 minutes, and at night the temperature regime is completely restored. The maximum tourist load per day is 825–925 people or more, depending on the operating mode of the Cave. Thus, the visiting regulations and the allowed throughput of the cave are currently chosen correctly. The number of tourists is not so large as to limit the visit to the Cave to protect the ice formations, especially since the first-year ice is renewed every winter.

Received June 28, 2023; revised September 6, 2023; accepted October 2, 2023

Variability of the Pechora Sea ice cover and the Barents Sea surface temperature during the season from October to June in 2002–2022 (except the season of 2011/2012) was studied on the basis of satellite observations and reanalysis ERA5. Influence of the sea surface temperature on the ice cover was also analyzed but without considering the other hydrometeorological parameters. Areas of the sea ice cover characteristics were calculated using data on the sea ice closeness obtained from the Advanced Microwave Scanning Radiometer 2 measurements. To analyze the variability of sea surface temperature, we used the average daily data of the European Centre for Medium-Range Weather Forecasts ERA5 reanalysis obtained by averaging hourly data. To study the spatial and temporal variability of sea ice cover and sea surface temperature, fields of daily averaged parameters were mapped. These maps and values of areas of the sea ice cover were analyzed. This made possible to reveal regularities of development of the sea ice processes in the Pechora Sea, to calculate the general trend of the sea ice area change over the considered period of time, and to divide the Barents Sea into four sectors with significantly different average values of the sea surface temperature: southwestern, northwestern, southeastern, northeastern ones. The seasonal and interannual variabilities of the Pechora Sea ice cover and the Barents Sea surface temperature were analyzed. To study the effect of sea surface temperature in different sectors of the Barents Sea on the sea ice area, the method of statistical analysis (Pearson’s linear correlation) was used for the monthly average data and the data, averaged over the sea ice season (from October to June) with different time lags. Significant correlation coefficients were obtained only for a two-month lag. With such a lag, high values of the inverse correlation coefficients were revealed between the sea surface temperature in the southwestern (up to –0.8) and northwestern (up to –0.6) sectors of the Barents Sea and sea ice area of the Pechora Sea, while in other sectors the correlation was significantly smaller or even below the significance level.

Received June 8, 2023; revised September 4, 2023; accepted October 2, 2023

The palaeogeographic scheme of the distribution of glaciers and ice-dammed lakes in the Altai during the last global glaciation (MIS-2) was compiled based on a detailed large-scale geomorphological survey. Analysis of geomorphological traces of glaciers of this time indicates that they occupied smaller areas than those of the first Late Pleistocene glaciation. By this means, the ice dams created by them were smaller that resulted in small sizes of ice-dammed lakes. The preserved levels of terraces indicate that during the first Late Pleistocene glaciation in the Kurai-Chuya depression system the ancient lake was the only one with a level of 2250 m and a total volume of 1.70 km³. During the second Late Pleistocene glaciation in the south-east Gorny Altai, another separate lake existed which was the Bartal-Kurai Lake with a level of 1700 m and a volume of 45 km³. This lake was dammed by the Mashey Glacier, which descended from the northern slopes of the North Chuaya Range. In the Chuya Depression, the existence of a landslide-dammed lake with a volume of 0.7 km³ and a level 1.750 m has been found. Its formation was not associated with glaciers of the MIS-2 stage. Direct dating of the last ice-dammed lake in the Chuya Depression with a level of 1950 m and a volume of 140 km³ has not yet been determined. This lake was dammed by the Kuehtanar Glacier, which descended from the southern slope of the Kurai ridge. The volume of ice-dammed waters of the MIS-2 time was an order of magnitude smaller than it was in the first Late Quaternary glaciation. This explains the much lower intensity of erosive and accumulative processes associated with the mega-flood occurred due to the breakthrough of the lakes during MIS-2.