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Vol 65, No 3 (2025)
Articles
Studies of the Institute of Geography RAS on the Karaugom Plateau in the Caucasus, 2025
Ice and Snow. 2025;65(3):376–377
376–377
Glaciers and ice sheets
Structure Stability of External Mass Turnover Fields of the Djankuat Glacier
Abstract
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.
Ice and Snow. 2025;65(3):378–396
378–396
Features of the Dynamics of Bezengi and Bashkara Glaciers with a Debris Cover in the Central Caucasus
Abstract
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.
Ice and Snow. 2025;65(3):397–410
397–410
Snow Cover and Avalanches
Automated Interpretation of Multi-Zone Space Images for Snow Depth Recognition: the Case of Western Yakutia
Abstract
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.
Ice and Snow. 2025;65(3):411–421
411–421
Observational Results of Evaporation from the Snow Cover Surface at the Research Base “Ice Station “Cape Baranova” (Severnaya Zemlya)
Abstract
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°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.
Ice and Snow. 2025;65(3):422–431
422–431
Thermal Regime of Permafrost in the Borehole Depending on the Snow Cover Thickness in the Area of the Polar Station “Samoilovsky Island” (Lena River Delta)
Abstract
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°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)·10–6 m2/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°C, respectively; in 2018, these temperatures were equal to: –6.81, –7.42, –7.86°C.
Ice and Snow. 2025;65(3):432–446
432–446
Features of Microwave Measurements of Cryospheric Formations Using UAVs
Abstract
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°. 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.
Ice and Snow. 2025;65(3):447–460
447–460
Isotopic Composition (δ18O, δ2H) of Snow Cover on the Yamal Peninsula
Abstract
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 δ18O = -20.207±3.3‰ and δD = -152.677±23.8‰. The linear regression equation for snow cover of the study area is δ2H = 6.8δ18O - 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 δ18O and δ2H; 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 δ18O and δ2H values than the upper ones. The average difference between the horizons was 2.83‰ for δ18O and 20.17‰ for δD. The equation of the relationship between δ18O and δ2H 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.
Ice and Snow. 2025;65(3):461–475
461–475
Sea, river and lake ices
Changes in the Ice Cover of the Russian Arctic Seas in the 21st Century Based on the Results of Climate Models of the CMIP6 Project
Abstract
Ice cover is one of the main parameters describing the state of the ice cover of various water areas. The simplicity of calculation determines the frequency of using the indicator in research work both for reading the seasonal course and interannual changes in the state of the ice cover, and for verifying model data or reanalysis data. In this paper, ice cover is calculated based on five data sources. The comparison is based on satellite data from the NSIDC DAAC archives October 26, 1978 – March 31, 2023; spatial resolution is 25×25 km, temporal resolution is 1 day; the data were collected by the SMMR, SSM/I, SSMI/S sensors on the DMSP program satellites, as well as the Nimbus-7 satellite) and OSISAF (product code OSI-401-d; March 1, 2005 – present; spatial resolution is 10×10 km, temporal resolution is 1 day; the data were collected by the SSMI/S sensor on the DMSP program satellites). Model data from the international CMIP (Coupled Model Intercomparison Project) project are used for comparison and verification. Of the more than 40 models of the sixth phase of the project, two were selected that provided the necessary data and were suitable in terms of spatial and temporal resolution – MPI-ESMI-2-HR and AWI-CM-1-1-MR of the Max Planck Institute and the Alfred Wegener Institute, respectively. For all obtained ice coverage series, the mean, standard deviation, range, correlation intervals, trend coefficients and standard error were estimated relative to the NSIDC series for the data intersection period of 19.09.2016–31.06.2023 in each of the Russian Arctic seas, as well as for the water area as a whole. Using the calculated statistical characteristics, satellite data on ice cover were compared with the results of modeling in accordance with different socioeconomic trajectories (Shared Socioeconomic Pathways, SSP) for both models, the quality of ice cover modeling was assessed, and scenarios were selected that most closely matched the satellite data for both the entire Russian Arctic water area and for individual seas. Based on the assumed optimal scenarios, possible changes in ice content were predicted.
Ice and Snow. 2025;65(3):476–486
476–486
Variability of the Pechora Sea Ice Area and the Relationship between Its Area and Wind Speed According to Satellite Observations and Reanalysis Data
Abstract
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 ERA5 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).
Ice and Snow. 2025;65(3):487–501
487–501
Long-Term Variability of the Timing of Freezing and the Duration of Ice Phenomena in the White Sea Based on Satellite and in Situ Observations for 1980–2020
Abstract
The long-term variability of the ice regime of the White Sea for the period 1980–2020 was studied. The reliability of the satellite data used was also assessed by comparing them with in situ observation data. We use the regular hydrometeorological monitoring data from eight marine observation points, as well as satellite microwave passive sounding data (NSIDC) with a spatial resolution of 25 km and a time step of 1–2 days to form series of the main elements of the sea ice regime (the characteristic dates of ice regime and duration of ice phenomena). The average statistical dates of the start freezing and the ice breakup for the entire water area of the White Sea and its regions were obtained. Regression analysis of the data showed that the start freezing and the ice breakup dates have shifted towards the winter months over the past 40 years. The shifts occurred at average rates of 7.4 days/10 years and 4.7 days/10 years, respectively, according to in situ observations, and 11.9 days/10 years and 4.1 days/10 years, respectively, according to satellite observations. Overall, over the past 40 years, the average duration of ice phenomena in the White Sea has decreased by 47 days according to in situ observations and by 62 days according to satellite observations. Comparative analysis of satellite and in situ data showed significant differences in the average values of absolute deviations (up to 70 days) in determining the characteristic dates of the White Sea ice regime; however, the time series of characteristic dates are in good agreement with each other (pair correlation coefficients of 0.76/0.82 between the time series of dates of start freezing and dates of ice break up). This proves the possibility of using satellite data to calculate the regime indicators of ice phenomena over a long period in order to identify patterns in the development of ice processes, assess their climatic trends and develop methods for forecasting ice conditions.
Ice and Snow. 2025;65(3):502–517
502–517
Ground ices and icings
Isotopic Signature (δ18O, δ2H) of Ice Wedges at Southern Limit of their Distribution near the City of Labytnangi (Yamal Peninsula)
Abstract
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 thermocrossional gully cut into the polygonal peatland and opening into a thermokarst lake. The values of δ18O (from –14.4 to –19.35‰) and δ2H (from –103.7 to –143‰) 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 δ18O values ranging from –11.5 to –15.5‰. 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 δ18O = –17.6‰ and δ2H = –126.7‰, while the vein penetrating one of the studied wedges was composed of thermokarst-cavitary ice with values of δ18O = –12.7‰ and δ2H = –93.3‰. 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 δ2H–δ18O 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.
Ice and Snow. 2025;65(3):518–532
518–532