Review: The paper presents brief results of studying the cryosphere of the Zeravshan and Hissar ranges. At the same time, the rate of change in the area of glaciers over the past almost a hundred years and the presence and degradation of permafrost during this time were considered. The actual description of the numerical method for estimating the depth of soil freezing based on data on the thickness of the snow cover and air temperature was also given. An example of the use of this numerical method for estimating the depth of soil freezing on slopes was given in order to map the cryolithozone of the Zeravshan and Hissar ranges. According to the calculations, the ground under the snow cover remains frozen on the Anzob pass from December to April. The power of the accumulated snow cover can reach one and a half meters or more. At the same time, the soil under the snow-covered surface freezes according to calculations by an average of 1.5 m. Thus, the proposed method for calculating the dynamics of the depth of soil freezing based on data on air temperature and the thickness of snow cover made it possible to assess the freezing of soil as a factor of soil stability during the construction of village and avalanche protection structures. Thus, the Anzob pass belongs to the area of seasonal freezing of rocks, taking into account the gradient of the average annual temperature of rocks, we can conclude that the appearance of permafrost rocks on the Hissar ridge can be expected at altitudes of more than 4,000 meters.

Keywords: geophysical research, cryolithozone, Tien Shan, thermometry, high-altitude permafrost, snow cover thickness, air temperature, mapping, freezing depth, numerical method

Review: When designing cryolithozone engineering structures, proper consideration of the thermal factor largely determines their subsequent reliable and safe operation. One of the important indicators when choosing design solutions is the coefficient of thermal conductivity of materials used in the construction of objects. The accuracy of determining the thermal conductivity coefficient also depends on the accuracy of determining the thermal resistance of heat-protective structures. The coefficient of thermal conductivity of materials is usually selected from the reference tables. When using mixtures of materials, the coefficient of thermal conductivity is determined by calculation. The purpose of this work was to compare the calculated values of the thermal conductivity coefficient of binary mixtures (a mixture of binder and filler) determined by the formulas of K. Lichtenecker and P. Schwerdtfeger. The comparison was carried out in the range of changes in the properties of materials characteristic of heat-accumulating and heat-insulating mixtures. It is established that for heat-accumulating mixtures, both calculation formulas give similar results. For thermal insulation mixtures, the results differ significantly. Moreover, the discrepancy for some ranges of changes in filler concentrations is hundreds and thousands of percent, which indicates a complete disagreement of the results obtained. The validity of applying one or another formula in different ranges of changes in the initial parameters for thermal insulation binary mixtures needs separate special studies. Note that the results obtained and the conclusions drawn can be extended to compare the formulas of K.Lichteneker and V.I.Odelevsky. At the same time, at this stage of research, it is not possible to reliably determine which of the two formulas should be used when calculating the thermal conductivity coefficient of thermal insulation mixtures.

Keywords: forecast, comparison, construction, ratio, binary mixture, thermal conductivity, cryolithozone, automobile road, formula, calculation

Review: The purpose of this study is to identify optimal strategies for the survival and development of small settlements in the Arctic region facing threats of a sharp change in the water balance of adjacent territories caused by Climatic changes. The territory of Yakutia occupies majority areas not only in the Arctic zone of Russia, but also in the world. The impact of Climate change in Yakutia will accordingly affect the local, regional, Russian and global levels. As an illustrative example, the small Yakut village of Khotochu, located on the banks of the Lena river and regularly exposed to the threat of flooding, is taken. To this end, the authors of this study collected materials from the archive of the municipality "Zhemkonsky 1st nasleg", which includes the village of Khotochu, official documents of departmental organizations, annual reports of heads of municipalities and already published scientific articles. Also in September 2021, field materials (interviews and questionnaire survey data) were collected directly in the village and in the surrounding areas. As a result, the authors identified the current socio-economic situation of this settlement, its history, the main problems faced by the villagers, the measures taken by administrative authorities at various levels, as well as the opinion of local residents. The vulnerability of the village of Khotochu to the negative consequences of water resources is characterized. Based on the study of the experience of adaptation of the residents of the village of Khotochu to the floods of the twentieth century, the decisions taken by the authorities to ensure the safety of population in Yakutia, based on the results of the study, recommendations were made to administrative and governing bodies of various levels to minimize hydrological risks and adopt more effective adaptive strategies.

Keywords: agriculture practices, adaptation strategies, hydrological risks, permafrost, floods, Climate change, the Lena river, Khotochu, Yakutia, The Arctic

Review: The paper considers the problem of monitoring seasonal changes in soil temperature in northern and mountainous areas in the light of ongoing climate changes. To study seasonal changes in soil temperature, a model site of the Moscow State University Meteorological Observatory was used with the ability to monitor air temperature, snow cover thickness, and ground freezing temperature and depth, which was a prototype of a system for monitoring the state of permafrost soils used in the Arctic and mountain territories. The paper presents the results of monitoring seasonal changes in soil temperature based on the results of numerical modeling of the penetration of seasonal fluctuations in soil temperature in 2014-2017 in MATLAB environment at the model site of the MSU Meteorological Observatory. The results of numerical simulation of the penetration of seasonal temperature fluctuations in the ground at the MSU meteorological site in 2014-2017 in the MATLAB environment are in good agreement with the thermometry data and, therefore, the developed calculation scheme shows fairly good simulation results. This makes it possible to use the calculation scheme to assess the thermal state of frozen soils and assess the stability of foundations and buildings and linear structures located on them in the conditions of the North and mountainous territories. Therefore, the presented methodology can serve as a good help for monitoring and preventing the destruction of the studied structures in the conditions of climate warming.

Keywords: geophysical research, numerical modeling, cryolithozone, freezing depth, North regions, Mountain regions, air temperature, permafrost, ground temperature, monitoring

Review: The subject of the study is the yedoma i.e. perennially frozen organic-bearing (>1–2% of Corg) and ice-rich (containing 50–90 vol. % of excess ice) silty, sandy loam and fine sand deposit of Late Pleistocene age. Yedoma with multi-stages syngenetic ice wedges (up to 15–20 meters high and up to 3.5 m wide) aged from 11.7 to 50 cal. ca BP often saturated with rock debris and gravel inclusions in intermountain basins and river deltas. The most famous regions of the Siberia, where yedoma is widespread, are the Kolyma and Yana-Indigirka lowlands, the New Siberian Islands, Lena and Vilyui River valley, Lena-Anabar, Anabar-Khatanga and Magadan regions, Yamal, Gydan and Taimyr Peninsula, Olekma, Biryusa valleys. In Alaska, these are slump on the Itkillik River and the Fox Permafrost Tunnel. Yedoma of the Klondike are known in the Yukon. Sections with large ground ice in yedoma were first described in the early 19th century on the Alaska and the New Siberian Islands, the idea of syngenetic accumulation of permafrost arose in the late 19th - early 20th centuries, the mechanism of syngenetic formation of yedoma was described in the middle of the 20th century. In the end of 20th century, studies of yedoma reached a new level. The oxygen and deuterium stable isotopes study of ice wedges together with radiocarbon ages of ice wedges gave the possibility to reconstruct the winter paleotemperature during yedoma formation. It was established the different genesis of yedoma also.

Keywords: ice wedge, Late Pleistocene, microcyclity, types of cyclicity, multistage, syngenetic, permafrost, yedoma, mesocyclity, macrocyclity