Том 64, № 3 (2024)

This study fills a gap in the long-term prediction of changes in parameters of the Elbrus glaciers, using the GloGEMflow-debris model to simulate the glacier evolution. The part 1 provides a detailed description of the model architecture. The model consists of three blocks in which the calculation of the surface mass balance, glacier flow and moraine transformation is carried out. The area and thickness of the moraine cover increase as glaciers degrade. This is important to consider, as a thicker layer of moraine reduces the ice melting. For predictive calculations, the data on temperature and precipitation for five SSP climate scenarios are taken from the CMIP6 project. A temperature index method is used to calculate the surface mass balance, taking into account the influence of the moraine cover: the ablation of pure ice is adjusted in accordance with the area and thickness of the moraine cover. The ice flow block is used to update the geometry of glaciers and moraine cover. The adaptation of the model to the glaciers of Elbrus includes the adjustment of the block of the moraine cover evolution, which corresponds to the geological features of the region. Thus, the accumulation of moraine on the glaciers of the volcanic peak through erosion of slopes and landslides can be neglected, it is considered to be the bottom moraine, thrown up along the shear planes, the main source of surface moraine on the glaciers of Elbrus. Hence, the debris-cover source in the model is specified to be the result of bedrock erosion rather than slope erosion. The paper discusses calibration processes that allow using simple modeling methods, such as the temperature index method for calculating the surface mass balance, and to simulate the real behavior of glaciers. Despite the fact that the validation of the model revealed a slight underestimation of mass loss at the beginning of the XXI century, the general patterns of mass loss are reproduced correctly, although the energy balance has not been explicitly described. Thus, the adjustment of the model ensures its adaptation to the glaciation conditions on Elbrus.

New estimates of the glaciation in the Taimyr Peninsula were obtained on the basis of the satellite data. The glaciation of the Byrranga Mountains was analyzed. These are the northernmost continental mountain glaciers, represented mainly by small forms of glaciation. They were in a relatively stable state until the end of the 20th century, but by 2003 the total area of them had decreased by 17% (Landsat images) compared to the USSR Catalog of Glaciers (1967). And even more (by 35–46%), of their area had decreased by 2022 (Sentinel-2) (CORONA images, 1966) in different basins that have been determined for all groups of glaciers. The use of the ArcticDEM database made it possible to correct the boundaries of the ice divides between the glaciers in the center of the glaciation. If we compare the results of 2022 with the 1967 Catalog, the contraction becomes more intensive – from 48.8 to 56%. Accordingly, the comparison with the Corona images of 1966 demonstrated a certain discrepancy with data of the 1967 Catalog – from 3 to 20% for different basins. Estimates of climatic changes in this region have been made, against the background of which the Byrranga glaciers are shrinking. The most intensive warming in Russia occurred here, on the Taimyr, during the period 1966–2021. The average annual air temperature had risen by 4–5 °C, but in summer the rate of warming was 2 times lower than the annual means. This means that in addition to the air temperature rise, other factors contribute to the accelerated melting of the glaciers. Thus, according to the ERA5-Land reanalysis, a significant increase in the radiation balance was identified (up to 3 W/m²/10 years, which for the period 1966–2021 amounted to 5% of the regional mean), which probably occurred due to a decrease in the surface albedo.

The isotopic composition (δ¹⁸О, δ²Н) of ice sampled during core drilling of a glacier in the crater of the Ushkovsky volcano in the summer of 2022 (new core) was studied. The ice core 14 m long dates from 2006 to 2022 and covers 16 years of accumulation. The values of δ¹⁸О and δ²Н of the ice vary from −16 to −24‰ and from −110.5 to −177.7‰ at average values of −20.5 and −150.2‰, respectively. The deuterium excess varies in depth from 8.7 to 21.3‰ at an average value of 13.7‰. In the isotope diagram, the values of δ¹⁸О and δ²Н form a linear trend described by the equation δ²Н = 7.47 × δ¹⁸О + 2.9 (R² = 0.98), the slope of the line, different from the global meteoric water line, reflects the mixing of summer and winter precipitation. Ice formed by summer precipitation has high values of δ¹⁸О (δ²Н) against a background of low d-excess, while ice of the winter season, on the contrary, has low values of δ¹⁸О (δ²Н) and high d-excess. Changes in the values of δ¹⁸O and δ²H of ice in depth proceed in antiphase with changes in d-excess, which reflects the dominant role of seasonal accumulation in the formation of the isotope record. The differences in the average values of δ¹⁸O and δ²H of the ice from the new core and similar values of ice from the core previously taken in the same crater of the Ushkovsky volcano are due to a change in the structure of the glacier’s alimentation – an increase in the amount of precipitation in the summer-spring season and a decrease in precipitation in the winter period. In addition to changes in the proportion of accumulation of the seasonal precipitation, the isotopic composition of ice is influenced by changes in the source of water vapor, from where air masses bring precipitation to Kamchatka. The use of the d-excess value allowed us to establish that the isotopic parameters of the ice of 2011−2012 and 2021−2022 annual layers were influenced by a pronounced positive anomaly in ocean surface temperatures, which is confirmed by HadSST observations. Thus, the isotopic parameters of glacial ice may serve as an indicator of climate change in the Pacific region.

The physical factors having influence on albedo of snow cover, as well as the main methods for its parameterization in models of natural systems, are considered. Numerous studies by various authors have shown that the most important characteristics determining the snow albedo in the near infrared range (hereinafter referred to as NIR) is the size of snow grains and crystals, and in the visible and UV ranges – the presence of impurities, primarily dust and soot. We have proposed the new scheme for parameterizing the albedo of snow cover, taking into account most of the processes and factors important for the metamorphism of snow and changes in its stratification and microstructure, namely: the influence of weather conditions during snowfall, its age, density and rate of background pollution, air temperature and solar radiation intensity, as well as the height of the Sun (angle of the Sun above the horizon). The proposed parameterization scheme is introduced into the LSM SPONSOR model. A new scheme for parameterizing snow albedo as part of the LSM SPONSOR model was tested using long-term observational data. Observational data were obtained for four ESM-SnowMIP project sites located in the mountainous regions of Europe and North America: Col-de-Porte (France), Weissfluhjoch (Switzerland), Senator Beck and Swamp Angel (USA, Colorado). The series of observational data on the surface noon albedo are 20 years long for the first two sites, and 10 years long for the rest. When compared with the old scheme for parameterizing the albedo of snow cover in the LSM SPONSOR model, based on the dependence of the albedo only on the age of the snow, the new scheme showed a significant increase in the quality of albedo calculations: the correlation coefficients between the observed data and the calculation results are 0.78–0.83, which gives determination coefficients of 0.61–0.69. The new scheme makes it possible to obtain unbiased albedo estimates with statistical distribution characteristics that practically coincide with those obtained for observational data. The set of test sites covers the specific conditions of snow formation in the mountains, both in forested and treeless zones, so the scheme can be recommended for calculating albedo in a wide range of mountain landscapes. The quality of the scheme is also confirmed by the fact that the calculations were carried out with the same values of all model parameters and coefficients for all four test sites located in different climatic conditions.

The results of analysis of major, minor and trace elements in snow and lake waters collected in January – May 2023 within the areas of location of Russian and Belarusian research stations are presented. The samples of snow and surface waters on King George Island (Waterloo), Schirmacher, Molodezhny and Vecherny oases, Larsemann Hills, as well as the Banks of Pravda and Ingrid Christensen were collected. The concentrations of 25 macro- and microelements were determined using the ICP-MS method, and the main ions were determined by titro- and turbidimetric methods. The maximum concentration of sodium (14.95 mg/l) was detected in the snow cover near the Mirny station; here, its average concentration is the highest as compared to other stations (4.65 mg/l). The lowest sodium concentrations (0.30–0.41 mg/l) are characteristic of the snow cover in the Molodezhny Oasis. Among the minor and trace elements iron is dominated at the majority of stations. It is shown that the investigated lakes of the Larsemann Hills (Low, Reid and Stepped) are sodium chloride in composition, the Lake Kitezh on King George Island (Waterloo) is sulfate-chloride calcium-magnesium, the lakes in the Vecherny Oasis are hydrocarbonate-chloride sodium, and Lagernoye Lake in the Molodezhny Oasis – chloride-hydrocarbonate magnesium-calcium. The revealed differences in the hydrochemical composition of snow and surface waters are conditioned by the distance from the coastline and protection from sea aerosols, as well as due to anthropogenic impact. The studies have shown that the snow and lakes of the coastal zones of the Larsemann Hills and the Pravda Coast in the vicinity of Mirny station are subject to the greatest impact of marine aerosols, and the least impact is the zone of the Schirmacher Oasis, most distant from the coast, near the Novolazarevskaya station. The importance of developing the research within the limits of one hydrological year aimed at estimating the inter-annual variability of hydrochemical parameters and revealing trends of changes with regard for various impact factors is shown.

The study of massive ices is of interest both for the purposes of paleogeographic reconstructions, and for solving engineering and geocryological problems. Despite the widespread distribution of massive ice beds in the cryolithozone, the problem of spatial identification of them and mapping has not yet been resolved, which is mainly due to the difficulty of determining and understanding the processes of their formation. The paper presents the results of studying the methane content as a genetic trait in massive ice beds along the coast of Eastern Chukotka. In 2016–2022, our team studied variations in the methane content in 4 massive ice beds and host deposits using the “headspace” method. The CH₄ concentration in ice and air bubbles ranged from 1 to 1582 ppmv, which made it possible to suggest the genesis of each bed and compare it with previously proposed hypotheses of their formation based on the earlier made cryolithological and oxygen isotope analyses. The study has confirmed the intra-ground (median methane concentration of 432 ppmv) and buried (2 ppmv) genesis for two beds. For the third one, the issue of its genesis remained debatable, and in the fourth bed, the obtained results have thrown doubt on the previous hypothesis about the intra-ground genesis of ice, since the recorded methane concentration was found to be close to the atmospheric one. Despite the limitations of the “headspace” method shown in the paper, it was manifested as the adequate way for the field studies when transportation of frozen samples to the laboratory is impossible.

The paper demonstrates realization of an experimental method of shock destruction of ice in order to study its specific energy of destruction and strength under various annealing conditions. Ice was prepared by layer-by-layer freezing of distilled water. The ice had a polycrystalline structure with a grain size of several fractions of a millimeter, judging by its ability to be broken into submillimeter fragments under the influence of shock load. It was shown that ice samples can be stored for a long time (several days) at a temperature of –18 °C without changing their physical characteristics. Annealing of ice for more than 5 hours at a temperature of –1.5 °C resulted in a decrease in the diameter of the holes formed on the ice surface by impacts of the ball by 20% and in an increase in the strength of the ice by 80%. Many hours of annealing at a temperature of about 0 °C caused the opposite results: the diameter of the holes increased by 10–20%, and the strength decreased. The increase in ice strength at the annealing temperature of –1.5 °C was explained by a decrease in the specific surface energy of formation of cracks and a decrease in the size of the fragments into which the ice breaks. The decrease in strength at the annealing temperature of 0 °C is explained by ice recrystallization processes, which results in a decrease of the density of microcracks in the ice lattice, and in an increase of the size of fragments. Thus, annealing can significantly affect the strength. To strengthen ice, the annealing temperature must be high, but not too close to the melting point, so that noticeable recrystallization does not occur, leading to a loss of strength of the material.