The regularity and variability of accumulation, ablation, and mass balance distribution on the Djankuat Glacier were investigated to assess the spatio-temporal stability of its external mass turnover fields. A 2019/20-2023/24 time span, characterized by varying degrees of abnormality in the annual budget parameters, was selected as a case pentad for testing. Interannual differences in snow accumulation and melting patterns affect the spatial structure of the fields - obvious shifts of maxima and minima areas are noticed, inter alia. Nevertheless, persistent structural similarities across years indicate a certain degree of temporal and spatial stability. The present analysis employs the field similarity hypothesis originally developed by V.V. Popovnin (1989), which evaluates the variability of the functional relationship between gridded balance parameters and those averaged either over corresponding alti-morphological zones or over the entire glacier. For each grid node, variation coefficients of normalized values are calculated, followed by correlation analysis between the normalized node values and the corresponding zonal and glacier-wide averages. Concerned are both year-to-year correlations and the stability of annual fields relative to the long-term average pattern. Eventually the plots with the highest and lowest stability indices are identified within the glacier area. The alti-morphological zonation is found to align more consistently with the similarity hypothesis than glacier-wide averages. Among the three studied mass-balance parameters, the ablation field demonstrates the greatest stability, whereas the accumulation field exhibits the highest variability. Correlations between annual and multi-year fields exceed those between two arbitrary years. Obtained results can be applied for indirect mass-balance plotting and calculations as well as for predicting accumulation, ablation and overall mass balance patterns.
The article presents results of comparison of the ERA5-Land reanalysis data with results of direct (in situ) measurements of snow depth and the solid precipitation in the permafrost zone in the Magadan Region (Northeast Russia). The analysis was based on daily observations of 21 weather stations (9-850 m a.s.l., 2010-2024) and the authors' data from 12 stationary snow measuring stakes installed at thermometric boreholes of the regional permafrost monitoring network (175-1182 m a.s.l., 2022-2024). The snow depth on the stakes was recorded at a given time interval using camera traps. The ERA5-Land grid nodes closest to the observation sites with a spatial resolution of 0.1 degrees x 0.1 degrees (similar to 9 km) were used for the comparison with regard for differences in elevation between grid cells and observation sites. The results indicate that the ERA5-Land reanalysis systematically overestimates snow depth (on the average by 27 cm or 168%) and solid precipitation (on average by 6 mm or 113% for the period October-April) compared to in situ measurements. The average correlation coefficient between reanalysis data and observations is 0.73 for snow depth and 0.84 for solid precipitation. Divergence increases in mountainous areas and for stations located on the coast of the Sea of Okhotsk. The dependence of the overestimation of snow depth on the elevation of the observation point was revealed. Thus, the overestimation of snow depth reproduced from the reanalysis data increases up to an absolute elevation of about 500 m, but on levels higher 500 m, this dependence changes to the opposite. ERA5-Land shows earlier snow cover formation and later melting in comparison with observations. In addition to the overestimation of solid precipitation, further sources of uncertainties are the low spatial resolution of the ERA5-Land data and the lack of consideration of sublimation and wind-driven snow transport in the model. The findings contribute to a better understanding of the capabilities and limitations of using the ERA5-Land data in the mountainous permafrost regions.
The results of a study of the long-term climatic changes in the "surface air-soil" system to a depth of 3.2 m in the western section of the Baikal-Amur Mainline (BAM) railway are discussed. The monthly average minimum and maximum ground temperatures and characteristics of seasonal freezing and thawing are considered. There are clear regional differences in climatic conditions for the two groups of weather stations. The first group (Lena-Angara plateau and Pre- Baikal depression) is characterized by moderate winter cooling and summer warming in soils with positive mean annual temperature. The type of permafrost thermal regime is long-term seasonal freezing. The second group (Stanovoy Upland basins) is characterized by both moderate (isolated cases) and strong winter cooling in soils. Deep (more than 3.2 & mcy;) seasonal freezing prevails, which in some landscapes merges with permafrost. In summer, the ground warming is moderate and weak. Very weak warming is characterized by thawing only to a certain depth. In most basins, the mean annual temperature is negative throughout the soil profile. The types of permafrost thermal regime in the basins are long-term and deeply seasonally frozen type. Current changes in the climate indicators of the surface air and soil have been identified. Their good consistency has been noted. Positive linear trends in precipitation, air and soil temperatures have been recorded. The BAM region shows significant warming, especially in winter.
During the summer expedition 2025, glacio-climatic observations were carried out on the Levyi Aktru glacier, which marked the beginning of permanent monitoring. Assessments of the glaciological parameters of the Levyi Aktru and Vodopadny glaciers were also carried out using geodetic methods. Interesting features of the altitude distribution of snow accumulation were revealed, and the contribution of summer snowfalls to the variation of the glacier radiation regime during ablation period was noted. Spectral analysis of data series revealed a significant role of mountain-valley circulation in the formation of the thermal regime over the glacier surface, as well as the influence of synoptic variability on the cloudiness regime and the course of relative humidity over the glacier. The obtained data are necessary to identify the mechanisms of Altai deglaciation, assess the glacial component of runoff, and verify models of glacial systems. In particular, calculations of the variability of the main glaciological parameters using the Oerlemans minimal model using measured mass balance characteristics (1977-2012) showed that the Levyi Aktru glacier can be used as a model object.
The paper presents the results of remote studies of cryospheric formations in the microwave range using unmanned aerial vehicles (UAVs). For these purposes, a radiometric receiver with a frequency of 34 GHz with a bandwidth of 2.3 GHz with a fluctuation sensitivity of 0.05 K at a time constant of 1 s was installed on board the UAV. The directional pattern of the corrugated antenna was about 10 degrees. It is shown that this method of monitoring in the millimeter range of media containing ice inclusions is an urgent task, especially in hard-to-reach places. There are a number of difficulties in interpreting the obtained brightness temperature of the radiating medium, which characterizes the power of thermal radiation. The first difficulty lies in the fact that the obtained value of this temperature depends on the angle of observation, therefore, at the time of radiometric studies of cryospheric formations, it is necessary to measure the position of the UAV in space (pitch and roll angles). In addition, it is necessary to take into account the terrain, namely the angles of its inclination relative to the horizon. The second difficulty in interpreting the data obtained from microwave measurements of thermal radiation power is the peculiarity of the medium under study. For example, for a plane-layered three-layer medium with a relatively thin intermediate layer, interference of the brightness temperature is observed, both on vertical and horizontal polarization. Inclusions in cryospheric formations with sharply different dielectric characteristics from the medium itself, for example, gas bubbles in ice, should also be taken into account. The work will be of interest to researchers involved in monitoring various cryospheric environments, both for practical (ice crossings) and scientific (glaciers) purposes.
The paper analyzes long-term temperature monitoring data in a borehole at the station "Samoylov Island" in the Lena River delta. Temperature measurements over 12 years (from late 2006 to early 2019) show a warming of permafrost at a depth of 26.5 m by 1.3 degrees C. At the same time, air temperature does not show a noticeable rise during this period. To identify the factors influencing the temperature in the borehole, a numerical simulation of the soil temperature changes was carried out. The simulation was performed taking into account the warming effect of snow cover on the the freezing/thawing processes of the upper active layer. Based on the modeling results, it was concluded that the warming of the borehole is associated with increasing in the thickness of the snow cover due to the construction of buildings that accumulate snow around the borehole area. The thermal diffusivity of soils near the borehole at different depths (from 10 down to 21 meters) is amounted within a range of (0.88-1.18)& sdot;10(-6) m & sup2;/s that was determined using the 12-year temperature records (from 2006 to 2019) of seasonal temperature fluctuations at different depths. The time necessary for the borehole to reach a new thermal regime under conditions of an increasing snow thickness accumulating near the borehole was estimated. A new steady-state regime of the borehole was determined, in which the average temperature values at depths of 15.75, 20.75 and 26.75 meters may reach by 2062 are as -4.8, -5.1, -5.5 degrees C, respectively; in 2018, these temperatures were equal to: -6.81, -7.42, -7.86 degrees C
The article presents a methodology for mapping the depth of snow cover in 5 areas of Western Yakutia using field data and automated interpretation of the depth of snow cover using the unsupervised classification method (classification without training) of a multi-spectral space image obtained in the spring in the area under consideration. Field snow surveys in the study area were carried out in March-April 2024 at 52 points. The depth of snow cover in March ranged from 28 to 70 cm, and its density from 0.12 to 0.21 g/cm3. Landsat-8 / OLI images closest to the dates of field snow surveys were used as initial images to identify differences in the distribution of snow depth in the areas under consideration. We created a map of the depth of snow cover for the areas under consideration Muna, Udachny, Aikhal, Nakyn and Mirny in two stages. The first stage included an analysis of the spatial differentiation of snow cover using a combination of 5-4-3 Landsat-8/OLI bands. Then, to interpret the depth of snow cover, this multispectral image was divided into classes using the unsupervised classification method in the ArcGIS 10.1 program, and the resulting classes were compared with field research materials. According to the results of the conducted study of snow depth mapping, it was revealed that the lowest snow depths are typical for the lower parts of the slopes, as well as for the slopes of windward western and northwestern exposures. The average thickness of the snow cover occurs in the middle and lower parts of the slopes of leeward and, less often, windward exposures. The greatest snow depths are formed on the watershed and upper parts of the slopes of leeward exposures, which is explained by the large amount of snow and increased turbulence of air masses in the upper parts of the watersheds. In addition, the greatest snow thickness is typical and for river valleys, in depressions, as well as on man-made landscapes and residential areas. Comparison of the results of automated decoding (uncontrolled classification) with field snow measurements confirmed the applicability of this method in differentiating the depth of snow cover.
In small and medium-sized rivers of the permafrost zone, ice formation lasts for most of the year, and the ice cover often grows to the bottom along the entire length or in some of its sections. However, its impact on the morphology and dynamics of the riverbed, runoff, sediment, dissolved substances, and surrounding deposits is still unexplored. Observations on the formation and destruction of ice cover, freezing and thawing of riverbed sediments, and water turbidity on three small and medium-sized rivers were made in Central Yakutia. The data obtained from hydrographic stations of the Yakutsk Hydromet Office in 2008-2022 were used for our analysis. The character of the river's freezing, whether the ice cover grows to the bottom along the entire length of the river or only in certain areas, depends on its morphology. Even in the absence of water sources in winter, lenses of unfrozen water still remain in the deepest (more than 1.5 m) sections of rivers, such as pools of beaded channels or meandering rivers. Local taliks up to 4 m thick are preserved under sections of the river with floating ice, while under sections of the rivers with bedfast ice, the sediments completely freeze in winter. On rivers with bedfast ice a significant part of the snowmelt runoff passes over the ice cover. The presence of ice in the riverbed promotes rising of water levels and increased water flow rates, but at the same time, it protects the sediments on the bottom and banks of the river from thawing and subsequent erosion. The peak of water discharges during the spring flood on the smallest rivers passes over the ice; but as the size of the river increases, the peak of water discharge shifts to later dates, so it occurs on the ice-free riverbed. Thus, the effect of spring floods on the erosion of the bed and banks of rivers with bedfast ice is reduced due to the energy expenditure of the water stream in the first phase of the flood on the destruction of ice filling the channel and the thawing of the bed and banks material. This phenomenon is more pronounced on the smallest rivers, which have lower thermal energy, than on larger ones.
The microelement composition of the dust fraction of the snow cover of the Chita city (Zabaykalsky Krai, Russia) in winters of 2023-2024 was examined. For several years, Chita is known as one of the Russian cities with the most polluted air, and therefore it has been included into the Federal project "Clean Air" to reduce the level of emissions into the atmosphere by 2026 from 67.1 thousand tons (2017) to 23 thousand tons. In this aspect, this study of the content of trace elements in the snow cover was performed. The X-ray fluorescence analysis method was used to examine 75 samples of dust from snow, taken in various functional zones. The results revealed the distribution of chemical elements in the snow cover, depending on the level of technogenic load. The industrial zone and sites along transport routes are the most polluted, while the lowest levels of trace element accumulation are typical in the parking and recreational zones. Increased concentrations of Fe, Br, Sr, Sn, Sb, W and Th were recorded in the industrial zone, while Ti, V and Cu prevailed near the transport routes. Analysis of samples by the enrichment factor did show a significant anthropogenic contribution for Sn, Se and Sb (EF > 10), with maximum values of the concentration factor for W (K-c up to 62.26 in industrial zones) and As (K-c up to 19.54 in residential districts). The total pollution index (Z(c)) ranged from 2.18 (recreational zone) to 8.52 (industrial zone), indicating a moderate level of common pollution. Comparison with background values for Eurasia revealed that increased concentrations of Sr, Cs and Ti in the Chita samples, while the content of heavy metals (Pb, Cu, Ni) was smaller than the median values in other regions. The study emphasizes the integrated influence of local industrial emissions, transport and regional geochemical background on the composition of snow dust in a sharp continental climate.
The purpose of the work is to determine the degree of change in the thermophysical characteristics of the snow cover during compaction. A new indicator, the "snow cover compaction coefficient", has been introduced. The dependences of the change in the main characteristics of the snow cover on the compaction coefficient have been obtained. The change in the following characteristics has been considered: thermal conductivity, thermal diffusivity, thermal resistance, thermal inertia, thermal stability, and the Fourier and Stefan criteria. A summary table has been constructed, which makes it possible to determine the form of relationship between the above main characteristics and the compaction factor. It has been established that the form of functional relationship between the thermal conductivity coefficient and the snow density plays a crucial role in the quantitative relationship between the characteristics and the compaction factor. For example, if we assume a linear relationship between the thermal conductivity coefficient and the density, the degree of reduction in thermal resistance during snow reclamation is proportional to the square of the compaction factor, while if we assume a parabolic relationship between the thermal conductivity coefficient and the density, the degree of reduction in thermal resistance is proportional to the third power of the compaction factor. The values of the considered thermophysical parameters are obtained from the compaction factor for the case of the dependence of the thermal conductivity coefficient lambda on the snow density rho in the form of a truncated polynomial of an arbitrary degree n. Graphical dependencies of individual indicators on the form of initial functional relationships of the initial values obtained theoretically and from experimental studies and field observations are presented. It is also shown that the percentage discrepancy in the calculation results caused by the choice of exponential function of the thermal conductivity coefficient on density increases for almost all of the thermal properties with an increase in the value of the compaction coefficient and considerably exceeds the value allowed in engineering calculations. For example, the discrepancy of thermal resistance of snow cover when the compaction coefficient is 2.0 is 50 %, and with compaction coefficient equal to 4.0 it is 75 %. The main quantitative relationships of change in thermal conductivity coefficients of snow and thermal resistance of snow cover depending on the compaction degree has been formulated
Two field campaigns to study snow cover on the territory of the Yamal Peninsula were undertaken in the spring of 2017-2019 by the scientists of the Earth Cryosphere Institute. One of the study topics was isotopic composition of snow cover and its changes under the influence of external factors. The average values of the snow water isotopes are delta O-18 = -20.20 +/- 3.3 parts per thousand and delta D = -152.67 +/- 23.8 parts per thousand. The linear regression equation for snow cover of the study area is delta H-2 = 6.8 delta O-18 - 15.5 Deuterium excess has an average value of 9.6%% with a range of 27.5%%. The isotopic composition of fresh and old snow in high-latitude areas has clear differences. Old snow has higher values of delta O-18 and delta H-2; lower values of slope of the regression line and intercept. The isotopic composition of the snow cover does not depend on the location of the sampling points on the peninsula and depends rather on the height and density of the snow cover. The dependencies of the isotopic composition of fresh snow on weather characteristics were confirmed according to weather station data in Salekhard in 1996-2000. The deeper parts of the snow profiles have higher delta O-18 and delta H-2 values than the upper ones. The average difference between the horizons was 2.83% for delta O-18 and 20.17% for OD. The equation of the relationship between delta O-18 and delta H-2 in the deeper horizons has a lower slope and intercept values, as a result of deep hoar horizon metamorphism. The isotopic composition of snow lying on the lake ice surface is heavier than on the soil surface due to its lower height and the influence of lake water during uneven freezing of the water.
This review provides the present-day assessment of natural environment state of the Svalbard Archipelago in the first quarter of the 21st century. In recent decades, the region was subjected to significant environmental changes due to fast climate warming associated with the Arctic amplification, when rates of the surface temperature growth exceeded the global means by several times. This resulted in marked transformation of the local ecosystems. The key environmental factors, including (1) climate, (2) oceanography, (3) sea ice, are considered in the first part of the article. The paper presents current trends in surface air temperature and sea ice, as well as the dynamics of Atlantic Water inflow into the archipelago's fjords. Although Svalbard is among the most accessible and thoroughly studied regions of the Arctic, there are significant gaps in knowledge due to technical and methodological difficulties. The problems involve fragmented and incorrect data on the atmospheric precipitation, a lack of year-round oceanographic observations, and insufficient understanding of the impacts of Atlantic water on the fjords. These aspects open ways for future research, with a particular emphasis on interdisciplinary approaches that may enhance understanding of ecosystem changes in the context of climate change.
The results of instrumental observations of sublimation from the snow cover surface on the Severnaya Zemlya archipelago in the vicinity of the Ice Base "Cape Baranov" are presented. The study used an instrumental method with two GG-500-6 weighing evaporimeters. Observations began on April 16, 2024, and continued until the snow cover disappeared. The coefficient of mutual correlation between the measurements of the two evaporimeters during the pre-spring period is 0.943. At temperatures ranging from -30 to -10 degrees C, sublimation does not exceed 0.01 mm/day, and its intensity varies between -0.0007 and 0.0005 mm/hour. It has been shown that during the pre-spring period, the average daily amount of sublimation is 0.01 mm/day. In May, the average rate of sublimation is 0.0088 mm/hour, and during snowmelt the daily amount of sublimation rises to 0.51 mm/day. During the snowmelt period, 4.14 mm of moisture was lost through sublimation. Over the pre-spring and spring periods, the amount of sublimation determined by instrumental means is 7.76 mm. Adverse natural factors lead to underestimation of the sublimated moisture. To restore missing observations, the authors applied linear interpolation between adjacent measured values and recovery of gaps using P.P. Kuzmin's method. Recovery of missing instrumental observations using P.P. Kuzmin's method determines the amount of sublimation at Cape Baranov as 19.2 mm of moisture, while linear interpolation yields a value of 12.4 mm.
Based on the analysis of satellite images and aerial photography, the study revealed the formation of a debris cover of mudflow and landslide deposits on the surface of the Bezengi Glacier in 2016-2018 and the Bashkara glacier in 2019 in the Central Caucasus. It was found that while the main part the Bezengi glacier tongue was retreating, its right part under the debris cover continued to move forward and, in addition, began to shift to the left to the centerline. The right part of the glacier, which accelerated the movement, began to deform the proluvial/colluvial fan on the slope of the lateral moraine on a distance longer 600 m, with the formation of cracks and falls of the debris mass to the foot of the slope. The source of the Cherek-Bezengiysky River has shifted from the left side of the glacier to the right side and down the valley for a distance of 280 m in the period 2022-2024. As a result of the involvement of dead ice mass in the movement, in 2024 the Bezengi glacier terminus was at the same place that it was in 2014. After the snow-ice-rock avalanche on the surface of the Bashkara Glacier, the dynamics of its right flow changed. Below it there is a significant frontal mass of dead ice, which is not capable of engaging in motion. Therefore, the ice flow began to shift to the left, affecting the main left ice flow. As a result, in 2024, there was a change in the direction of the subglacial channel of meltwater runoff, the main part of which flowed towards Lake Bashkara, increasing its water inflow. This in the debris flow release into the lake and then to a change in the channel on the dam-break section below the Bashkara Lake with partial undercutting of its slopes. Due to that a threat of erosion of the bottom of the dam-break and a new outburst of the Bashkara Lake became quite probable. The events of 2024 in the areas of the terminus parts of the Bezengi and Bashkara glaciers showed that against the background of the ongoing degradation of glaciers, extraordinary events are still possible being caused by the restructuring of the subglacial drainage system in several years after the formation of a debris cover on the glaciers due to rock avalanches or debris flows.
In 2024, a polygonal peatland with ice wedges was studied near the city of Labytnangi (Yamalo-Nenets Autonomous Okrug, Russia). Ice wedges were uncovered in the wall of a thermoerosional gully cut into the polygonal peatland and opening into a thermokarst lake. The values of delta O-18 (from -14.4 to -19.35 parts per thousand) and delta H-2 (from -103.7 to -143 parts per thousand) of the ice were partially altered by secondary processes associated with flooding and subsequent freezing of free water. This led to the formation of thermokarst-cavity ice overlying the ice wedges, with delta O-18 values ranging from -11.5 to -15.5 parts per thousand. The central parts of the ice wedges were not affected by secondary processes, and their isotopic characteristics indicated the Holocene or modern age of the ice wedges. In the studied polygonal peat bog, the elementary vein had the values of delta O-18 = -17.6 parts per thousand and delta(2) H = -126.7 parts per thousand, while the vein penetrating one of the studied wedges was composed of thermokarst-cavitary ice with values of delta O-18 = -12.7 parts per thousand and delta H-2 = -93.3 parts per thousand. Thus, the wedge-shaped sprouts above the wedge can be both elementary veins (within the given polygonal peat bog) or secondary thermokarst-cavitary ice (directly penetrating the described ice wedge), which is important for the use of ice wedges in paleo-climatic reconstructions. The relationship of delta(2) H-delta O-18 values of thermokarst-cavitary ice indicates open system conditions, when secondary ice was formed by gradual freezing of sediments connected to a large water reservoir, which may be a nearby thermokarst lake. Probably, the episode of significant thawing of ice wedges was associated with flooding of this part of the peat bog by a nearby lake. Isotope studies of underground ice are a reliable tool for establishing the paragenesis of different types of ice exposed in one outcrop.
The aim of the study was to estimate the agreement between the isotope composition of snow cover and precipitation in Moscow during the winter season of 2023/24 characterized by a particularly deep snow cover. We sampled selected layers in snow cover on the campus of the Lomonosov Moscow State University (MSU). All precipitation falling from late November 2023 to late February 2024 at the Moscow State University weather station was sampled. Stable oxygen and hydrogen isotope (delta(18)& Ocy; and delta(2)& Ncy;) composition was analyzed in snow and precipitation samples, and the deuterium excess (dexc) has been calculated. It has been found that equations of delta H-2-delta O-18 ratio in precipitation and snow cover are similar. In February, the snow column showed an expansion of the range of delta 18O and delta H-2 values, as well as a general trend of increasing of delta O-18 values by 1.2-0.6 parts per thousand and a decrease in dexc values compared with December-January precipitation. This is most likely due to the aging processes of the snow cover, such as the formation of ice crusts and horizons of loose snow in the lower layers of the snow thickness. In March, the isotopic contrast of the snow column was less pronounced, and during the period of active snowmelt in late March, the range of variations in delta O-18 and delta H-2 values was minimal. It has been shown that, in general, during the winter period of 2023/24 in Moscow, the isotopic characteristics of the snow cover were in good agreement with the weighted average isotopic data for all precipitation fallen during the observational period. That happened mostly due to the conditions of the winter period (predominance of snow precipitation, rare short thaws). Under these conditions partial melting resulted in the formation of ice crusts in the snow cover, but prevented the loss of meltwater
Variability of the Pechora Sea ice area, wind speed at a height of 10 m and ice thickness were studied for the period from 2002 to 2023 (excluding the 2011/12 season) using satellite and reanalysis data. The influence of wind on the sea ice area was analyzed. The sea ice area values were calculated based on the product of sea ice concentration according to the AMSR2 satellite measurements. To analyze the wind variability, the daily average ER A5 reanalysis data was obtained by averaging hourly data. To analyze the sea ice thickness, irregular ICESat track measurement data over the Pechora Sea region were used. To study the spatial and temporal variability of the sea ice area and wind, maps of daily average parameter fields were constructed. Visual analysis of the maps and quantitative analysis of the sea ice area and wind values allowed to identify patterns in ice cover changes in the Pechora Sea, wind speed variability, and to highlight the days when intense cyclones were observed over the sea. To study the effect of wind on the sea ice area, the Pearson linear correlation was used for the days when the wind speed exceeded 7 m/s and had predominantly one direction over most of the water area (more than 75%). High values of inverse correlation were found only considering a time lag of two days. With such a lag, higher values of the inverse correlation coefficients between wind speed and sea ice area were found for the autumn-winter period (up to -0.39). During the passage of cyclones through the Pechora Sea area, a correlation was observed between the wind speed and the sea ice area (-0.32).
This paper presents the results of a quantitative assessment of changes of the Hoffman Glacier, the largest glacier in the Subpolar Urals, occurring over the period 1951-2024. Aerial photographs from 1951, current Sentinel-2 satellite images, laser rangefinder data from the ICEsat-2 satellite, as well as historical and modern ground-based photographs were used. The results show that in 1951 glacier area was 0.36 +/- 3 % km2. This value was almost identical to the results of a ground-based phototheodolite survey of the glacier area carried out in 1929. By 2024, the glacier area had decreased by 33 % and amounted to 0.24 +/- 8 % km2. The reduction in the glacier area was accompanied by a decrease in its surface height. Over 73 years (1951-2024), the glacier surface elevation on the ICESat-2 profile decreased by 45 +/- 11 m and reached the altitude of 647 +/- 11 m. The average rate of the surface lowering amounted to 0.6 m/year. A comparative analysis of the dynamics of changes in the Hoffman Glacier size and climate data in this region suggests that the conditions for the existence of glaciers in this region have significantly worsened at the turn of the centuries. With a relative stability of winter precipitation, the number of years with positive temperature anomalies in summertime has sharply increased (with a continuous series of such anomalies since 2003). In addition, a certain increase in the short-wave radiation caused by reduction in the cloudiness has been observed over the past 20 years. The rise in summer air temperatures and the increase in the shortwave radiation cause the glacier mass balance to become even more negative and the rate of its shrinkage to increase. How long the Hoffman Glacier will remain in its cirque part will dependon the further development of the climate scenario.
The ongoing degradation of the Djankuat Glacier is also reflected in the expansion of the debris cover on the ice surface. During the 56 years since the start of direct measurements in 1968, the debris-covered glacier area has grown from 2% to 20%. The layer of superficial moraine changes the structure of the heat balance of the glacier surface, significantly affecting ice ablation. A thin (<7 cm) cover can lead to increased melting of sub-debris ice, whereas as the debris layer thickens further, melting progressively weakens until complete vanishing after the debris cover thickness exceeds 1.5 m. Based on the results of a field survey of the debris cover in 2022, another, fourth map of the debris thickness was compiled, continuing a series of similar maps as of 1983, 1994 and 2010. The mean debris thickness varies greatly by altitudinal belts, and currently it reaches on average 60 cm throughout the glacier, which is more than twice the average all-glacier value for 1983. Thus, all the 4 debris surveys conducted over the years indicate that the hydrological role of the debris cover has always come down to an unambiguous effect of a general melt-rate weakening for the glacier as a whole. The total volume of moraine material increased 4-fold over the 39-year-long period 1983-2022, up to 275 thousand m & sup3;, despite the fact that the glacier area has significantly decreased over the same period by more than 1,5 times for both the physical surface and its orthogonal projection. The acceleration of debris mass growth over the last decade is demonstrated. Activation of denudation processes due to progressive deglaciation of the rock revetment above the firn basin causes a more intensive influx of colluvial material to the glacier. Together with the rise of the kinematic equilibrium line, this leads to an increase in the upper boundary of the debris-covered surface on the glacier.
A study of the chemical composition of snow at the oil fields of Khanty-Mansi Autonomous Okrug - Yugra (KhMFO - Yugra) was carried out from 2015 to 2023. The snow pH and total contents of heavy metals (Cr, Fe, Mn, Ni, Pb, Zn), ammonium and nitrate nitrogen, petroleum hydrocarbons, chlorides, and sulfates were analyzed using data of the environmental monitoring. The content of ammonium nitrogen in the snow corresponded to the background concentration, while the same of nitrate nitrogen exceeded the background magnitudes. A certain acidification of precipitation was revealed. In some sites, pollution of the snowmelt waters with petroleum hydrocarbons was found. Zn and Cr are the most commonly found heavy metals. To identify sources of pollution, a correlation analysis was conducted, establishing a relationship between snow composition and specific indices of technogenesis. The pH value of snowmelt water is in negative correlation with a number of flares used for burning associated petroleum gas. A weak positive correlation was identified between the content of petroleum hydrocarbons and pipeline accident rates. The content of Zn depends on the amount of drilling waste and is determined by the intensity of drilling operations. It was concluded that the composition of snow has a pronounced effect upon the ecological state of surface waters since melting of snow increases the content of nitrate nitrogen as well as the concentration of petroleum hydrocarbons. To determine the trends of atmospheric pollution, the monitoring results of 2015-2023 were compared with the data of 2005-2010. A decline in the concentrations of chlorides, sulfates, nitrates, petroleum products, and iron in the snow was found, which can be attributed to reduction of the volume of associated petroleum gas burned in flares and a lowering of the pipeline accident
