Vol. XXIX, No. 2 (March – April 2025)
Full issue:   EC_2_2025_engl_opt.pdf

CONTENTS

CRYOGENIC PHENOMENA IN SEAS AND OCEANS

  • Kharitonov V.V. Specific features of porosity distribution in various types of pressure ice ridges
    Abstract
    The study focuses on the porosity distribution of the unconsolidated part of various types of pressure ice ridges as a granulated medium. The porosity estimate was obtained by processing records of the rate of thermal drilling of ice ridges. The variability of the porosity of ice ridges caused by the action of gravity and the Archimedes force during ice ridge formation is analyzed. It is shown that the porosity distribution in the sails of first-year drifting ice ridges and ice ridges in the fast ice is approximately the same, but the keel porosity in the ice ridges of the fast ice is slightly shifted towards lower values. The porosity of the sail, the blocks of which are more elongated and thinner, is higher than the porosity of the sail composed of thicker ice blocks. The tendency to a decrease in the average porosity of the sail and keel of pressure ice ridges with the distance from the ice surface deep into the ice ridge is preserved with an increase in the age of the ice ridge, but becomes less pronounced.
    Keywords
    fast ice, first-year pressure ice ridge, second-year ice ridge, multiyear ice ridge, keel, porosity distribution, sail

GASES AND GAS HYDRATES IN THE EARTH’S CRYOSPHERE

  • Bukhanov B.A., Chuvilin E.M., Mukhametdinova A.Z., Krivokhat E.O. Nuclear magnetic resonance investigations of phase transformations in frozen hydrate-containing soils during interaction with salt solutions
    Abstract
    Experimental studies of phase transformations in frozen hydrate-containing fine sand samples during their interaction with frozen salt solutions have been conducted using low-field NMR relaxometry. The obtained results confirm that the amount of liquid water in the investigated samples increases with time as a result of salt transfer and pore hydrate dissociation. In addition to the pore hydrate dissociation and the supercooled water increase, a reverse process occurs, which is associated with the freezing of the pore solution as a result of a decrease of a salt concentration. The performed studies enable identifying the boundary of the area with the high liquid water content in soil systems in the direction of salt migration flow. In this case, the velocity of this front in the target samples was determined not only by the concentration of the contacting solution, but also by the initial content of the liquid water and the conditions of pore hydrate existence. Thus, the movement of the liquid water front in frozen sands containing metastable hydrates is about 30–40% faster than in similar soils containing stable hydrates, which is in good agreement with the results of previous studies. As a result, the developed NMR technique opens up great potential for permafrost and gas hydrate studies in general and, in particular, for understanding the contribution of non-equilibrium and equilibrium liquid water to the salt ion migration mechanism in frozen and hydrate-containing soils.
    Keywords
    permafrost, gas hydrates, NMR relaxometry, salt migration, hydrate dissociation, self-preservation, supercooled water, pore ice

PERMAFROST MICROBIOLOGY

  • Vlasov D.Yu., Ganyushkin D.A., Kopitsa G.P., Gorshkova Yu.E., Platonova N.V., Tikhomirova I.Yu., Pankratova L.A., Lessovaia S.N. Features of microbiota formation in the deglaciation zone (Eastern Mugur Glacier, Southeastern Altai)
    Abstract
    An analysis of samples of cryoconite and moraine material collected on the surface of the Eastern Mugur Glacier (Mongun-Taiga Ridge, Southeastern Altai) was carried out. The results of metagenomic analysis indicate significant differences in the microbiota of cryoconites at different altitudes of the glacier: at the maximum altitude, the absolute dominance of actinobacteria from the Kineosporiaceae family was noted; closer to the edge, actinobacteria from the Microbacteriaceae family predominated. Representatives with a wide ecological amplitude, as well as psychrophilic and extremophilic bacteria (representatives of the Kineosporiaceae and Geodermatophilaceae families) were found in the cryoconites, which probably indicates different pathways for the microorganisms to enter the cryoconites and possible differences in the time of their presence in these habitats. Actinobacteria are most adapted to the extreme conditions that develop in the cryoconites of the Eastern Mugur Glacier, which contributes to the accumulation of primary biomass and the formation of organomineral substances in cryoconite holes. As one approaches the edge of the glacier, the taxonomic diversity and proportion of microorganisms with a wide ecological amplitude increase, which is probably explained by the airborne transport of particles of moraine material settling in the cryoconites. In the surface moraine material at the edge of the glacier, proteobacteria (representatives of the Sphingomonadaceae family) turned out to be superdominants, which may be associated with the processes of initial soil formation.
    Keywords
    cryoconites, the Altai Mountains, mountain glaciers, microbiota

PERMAFROST ENGINEERING

  • Gorelik J.B., Zemerov I.V. Calculations of frozen soil thawing and refreezing processes near development wells
    Abstract
    Calculations of examples of frozen soils at temperatures of –3 and –6°С with both numerical and analytical methods demonstrated that for an analytical description of the frozen soils thawing during the well operation period, the problem statement in the Leibenson form can be used with the assignment of an exact solution in an unlimited part of space. The solution for the thawing radius of such a problem is written in a form close to self-similar. An exact analytical solution is obtained for the equation describing the change in the talik size upon its refreezing. It is shown that the time of refreezing of the talik depends not only on its size, but also on the history of its formation. It is established that there is boundary soil temperature value, below which the talik refreezing time is less than the time of its formation. At a soil temperature above the temperature value, the relationship between these times is inverse. At the final stages of well support design, it is recommended to rely on the results of numerical calculations of the parameters of thawing and reverse freezing processes using high-quality software products. The accuracy of the analytical method does not fully meet requirements for the accuracy of the forecast during design, but it allows for fairly reliably tracking of trends in the evolution of process parameters, preserves the order of calculated values, and ensures a high speed of their assessment. This allows us to recommend the use of the analytical method for operational assessments of thawing and refreezing processes at the preparatory stages of surveys for construction and in the design of well support structures, in monitoring studies, as well as at the stages of debugging standard computing programs for a specific task.
    Keywords
    permafrost, well support structure, thawing, refreezing, calculation methods

SNOW COVER AND GLACIERS

  • Kitaev L.M., Titkova T.B., Aleshina M.A. Modern trends in variability of average and extreme snow depths on the East European Plain
    Abstract
    The variability of average and extreme seasonal snow depth values across the East European Plains has been assessed taking into account regional characteristics of meteorological regime. The regional distribution of average and extreme (5th and 95th percentiles, minimum and maximum extremes) snow depth values has been clarified. A tendency for a long-term decrease in average and extreme snow depths along with an increase in air temperature and precipitation has been revealed. According to the results of regression analysis, the dependence of long-term dynamics of snow depth on meteorological characteristics is more pronounced for maximum extremes. The most significant contribution to changes in snow cover depths belongs to variability in precipitation. Difference integral curves indicate the presence of two negative phases of snow depth characteristics in 1985–1995 and 2005–2015, which corresponds to long-term features of atmospheric circulation. Based on data from reference meteorological stations, the accuracy of snow depth calculations using ERA 5-Land reanalysis has been estimated: the relative error reaches 45–50%, and linear trend coefficients differ by 1.5–3 times, which should be taken into account when using the calculated values.
    Keywords
    snow depth, air temperature, precipitation, percentiles, minimum and maximum extremes, regression analysis, seasonal and long-term variability

  • Fakaeva N.R., Demezhko D.Yu., Gornostaeva A.A., Khatskevich B.D. Thermal properties of the snow cover in Yekaterinburg
    Abstract
    The thickness and thermal properties of snow cover play a significant role in the formation of the thermal regime of the ground surface and an urban heat island in regions with cold or temperate climate. This article describes the results of laboratory and field studies of the snow thermal properties in Yekaterinburg carried out in 2023/24. The thermal conductivity vs density dependence for different types of snow, including snow contaminated with pollutants typical of Yekaterinburg, was investigated in laboratory using the needle probe method. A regional dependence of thermal conductivity of the snow on its density was plotted. The snow cover depth and the vertical distribution of snow density were measured in situ at the geothermal test site of the Institute of Geophysics, Ural Branch of the Russian Academy of Sciences. Based on these data and taking into account the obtained density vs thermal conductivity dependence, time sections of changes in the density, thermal conductivity, thermal diffusivity, and thermal effusivity of the snow cover in the 2023/24 season were constructed.
    Keywords
    snow cover, snow density, thermal conductivity, thermal diffusivity, thermal effusivity, needle probe, Yekaterinburg

CHRONICLE

  • Lupachev A.V., Zanina O.G., Fedorov-Davydov D.G. In memoriam Stanislav Victorovich Gubin (July 13, 1945–March 7, 2025)
    Abstract
    On March 7, 2025, at the age of nearly 80, just a few months before his jubilee, Stanislav Victorovich Gubin, Doctor of Biological Sciences, leading researcher of the Department of Soil Cryology of the Institute of Physicochemical and Biological Problems of Soil Science of the Russian Academy of Sciences (Moscow region, Pushchino), suddenly passed away. Stanislav Victorovich will be remembered as a remarkable permafrost soil scientist and experienced field worker.
    Keywords
    soil science, cryopedolith, micromorphology, permafrost-affected pedogenesis, cryoconservation