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Thermometric observations in the area of the Yamburg oil and gas condensate field in summer have been used to calculate the thermal diffusivity (K) coefficients of moss (Sphagnum fuscum), bushy lichen (Cladonia arbuscula), and two-layer samples of soil-vegetation cover, consisting of mixed vegetation (Empetrum nigrum, Vaccinium vitis-idaea, Carex arctisibirica) of different thickness and sandy soil. The thermal diffusivity for sphagnum moss and lichen have been calculated for the periods with different meteorological conditions. The K values, obtained during the experiment, are quite close to the previously published values of the thermal diffusivity for similar types of the land cover. An amplitude of daily temperature fluctuations at a depth of 12 cm under the cover samples decreases by 84-94 %. The amplitude of fluctuations decreases by 37 % in the upper layer of the cover with a thickness of 4.2-6.4 cm, depending on a type of the cover. An abnormally high increase in the thermal diffusivity of sphagnum moss was noted with an increase in air humidity and precipitation by the end of summer. This fact confirms the unique thermal insulation properties of sphagnum moss, which ensure the conservation of ice wedges in drained areas. It was found that at average daily air temperatures below 27 °C and relative air humidity above 49 %, the K values of the studied samples of the land cover can serve as indicators of their thermal insulation properties.

Reconstruction of paleoenvironmental conditions, origin of sediments and permafrost evolution as well as identification of cryogenic and paleocryogenic formations based on sediment cores (small fragments of geological record) are among key scientific problems of cryolithology. We have analyzed grain-size distribution, geochemistry, and water content of sediments from the permafrost section in the North of Pur-Taz interfluve (West Siberia). Moreover, we have described the floristic composition of plant remnants, their age and the cryostructures found within these sediments. Optical and electron microscopy revealed the micromorphological features of thin sections and specimens of rocks. Based on the sediment core data from the borehole, we have established the alluvial, lacustrine and proluvial origin of sediments. Furthermore, we have reconstructed the conditions of sedimentation in this area and have established the Karginsky age of these sediments. This age corresponds to formation of 3rd lacustrine-alluvial plain in the lower course of Taz river. The conditions of early diagenetic transformations of sediments as well as epigenetic and syngenetic permafrost were reconstructed based on cryogenic and post-cryogenic formations, cryostructures, microstructure and authigenic minerals. We were also able to reconstruct the Late Pleistocene sequences of freeze-thaw cycles in the upper part of the permafrost section of the Pur-Taz interfluve.

The current state and the quantitative estimates of glacial lakes on Svalbard are presented. These lakes were formed in depressions under modern recession of glaciation of the archipelago. Based on Norwegian aerial photography 2008-2012 and mosaics of Maxar Vivid 2013-2019 images of Svalbard area, 629 new glacial lakes have been identified. These lakes are located on deglaciated areas. A map of new lakes and their distribution by territory and altitudes are presented. Most of glacial lakes are located in western and southern parts of Svalbard, where large-scale glacier retreat has been noted. At the same time, new glacial lakes are formed mostly in the northern and eastern parts of the archipelago where most of the lakes have ice coasts. The total length of ice coasts of 306 lakes was (233.8 ± 0.6) km in 2008-2019, which is comparable to the length of the fronts of the outlet glaciers of Svalbard. The total area of glacial lakes is (173.1 ± 0.7) km², and their total water volume ranges from 2.1 to (2.3 ± 0.1) km³.

Autocorrelation characteristics of long-term time series of cells with the size of 1° x 1° of the sea ice area data array for the Northern Hemisphere are obtained. The temporal heterogeneity and spatial anisotropy in long-term variability of the sea ice area in the Northern Hemisphere are determined. The closest relationships between long-term monthly values of the sea ice area are typical for summer months. More than 49 % of maximum values of pair correlation coefficient are due to the connection of June and July, as well as July and August multi-year series in the array cells. This effect is a consequence of intense and massive summer melting of sea ice in the Northern Hemisphere and similarity of their long-term variability. The closest relationships in the neighboring cells of the array between the long-term monthly values of the sea ice area in all months of the year are noted for the east - west latitudinal direction. It accounts for more than 87 % of all maximum values of correlation coefficient. Spatial anisotropy is revealed throughout the entire area to the north of the Arctic Circle. The reason for this effect is determined by the features of sea ice seasonal formation (mainly from high latitudes to low latitudes) and melting (from low latitudes to high latitudes). These features are associated with seasonal changes in insolation. Long-term changes in sea ice area have similar direction and are determined by changes in meridional gradient of insolation. Another reason may be mainly meridional direction of sea ice drift in the Arctic Ocean. Areas with high and low levels of short-range spatial and temporal relationships in sea ice area dynamics in the Northern Hemisphere are determined.

The results of ground-penetrating radar studies in the complex of engineering and geological surveys at the design site of the cluster site of an oil and gas field in an area with a continuous spread of permafrost soils are considered. Drilling of geological wells with core sampling have revealed the presence of an ice ground lens with an ice content of up to 90 %. Comparison of the drilling results and the characteristic wave pattern on the ground-penetrating radar sections have allowed us to identify the area of abnormal changes in soil properties, which is interpreted as an ice-ground lens. High-amplitude diffractions of an electromagnetic wave are distinguished at the “ice-ground-peat” boundary, which, according to the authors, are due to the presence of wedge ice bodies. The lens of the ice ground has been contoured and its approximate volume has been calculated with the help of attribute analysis.

January 20, 2022 marks the anniversary of Nella Alexandrovna Shpolyanskaya, a well-known permafrost scientist focuseds on ground ice history, Doctor of Geographical Sciences, now a professor at the department of ecology, land management and nature management, Ukhta State Technical University.

Dr. Mikhail Nikolaevich Grigoriev, Deputy Director of the Melnikov Permafrost Institute SB RAS (Yakutsk, Russia) and Prof. Hans-Wolfgang Hubberten, former director of the Potsdam Unit of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (Potsdam, Germany) were awarded the Order of Merit of the Federal Republic of Germany in recognition of their outstanding contributions to the development of Russian-German cooperation in Arctic research. The ceremony of bestowal took place in the MPI’s conference hall in Yakutsk on October 6, 2021.

Eduard V. Severskii, Candidate of Agricultural Sciences, head of the Kazakhstan Alpine Permafrost Laboratory at the Melnikov Permafrost Institute, passed away on October 9, 2021. An eminent scholar and highly qualified permafrost researcher, Severskii devoted his career to the study and mapping of seasonally and perennially frozen ground and cryogenic phenomena in the high mountains of Central Asia. The fond memory of the remarkable scientist and personality will remain in our hearts forever.

The article integrates the results of half a century studies of Late Pleistocene-Holocene changes in climate, sea level and glaciation in the marginal zone of Antarctica in order to identify the chronology, parameters, mechanisms of these changes under the influence of global, regional and local factors. During the interstadial (MIS 3), the natural conditions here resembled modern ones, and the sea level in some areas exceeded modern marks. The development of glaciation of the marginal zone from about 26 000 years BP went on when the temperature fell and the sea level dropped by 30-50 m. The growth of glaciation on the shelf outpaced the growth of ice on the outskirts of the continent, leading to a moisture deficit in the interior regions. During the LGM, there was a thin (less than 300 m) glaciation of coastal and mountainous land areas, and a thick (more than 1000 m) glaciation on the shelf. Deglaciation of the marginal zone began about 17 000 years BP due to rising sea level and global warming. Holocene climate changes in most areas had a general trend: warming in the early Holocene to about 8000 years BP and 4000-2000 years BP, cooling 2000-1500 years BP, but also had local differences. The relative sea level rose in the regions from the early Holocene to the period 8000-6000 years BP; then it fell with a decrease in speed and even with a possible rise of the level 2500-1300 years BP; local differences in the amplitudes and course of the level were determined by local tectonics and dynamics of deglaciation. Deglaciation rates were high from the early Holocene to about 7500 years BP due to warming and marine transgression; then the speed dropped. The advance of outlet and shelf glaciers 6500 and 4500 years BP was associated with a decrease in sea level and cooling. In the period 4000-1000 years BP, outlet and shelf glaciers could also respond to changes in sea level, and ice domes expanded according to the “warming-increasing humidity-increasing snow and ice accumulation” pattern. During the Little Ice Age, moraines were created in some areas, registering a slight increase in glaciers due to cooling.

Data on the width of floodplain taliks in river valleys of the mountainous areas of the northeastern part of Russia and in some adjacent areas of the Far East were gathered and organized. The investigated region extends from the Arctic coast to the southern limits of the continuous permafrost area. To assess the talik width, the satellite images (possessing high resolution) of Google Earth and previously established landscape features were used. The catchment areas at downstream ends of the chosen 340 representative river sections varied from less than 10 to more than 200 000 km², talik widths - from 41 to 4100 m. The rivers were subdivided into 4 channel types according to the degree of its branching based on the previous studies confirming that the floodplain taliks were formed only by braided rivers on coarse-grained alluvium. The studied sites are generally evenly distributed both over the territory and according to the selected channel types. The changes in talik widths from marginal coastal to the central continental basins in relation to the river types are discussed in this paper. The parameters of the empirical power-law dependence of the talik width on the catchment area of the river are calculated. The obtained results assess a variation of the melting zone width within a given river catchment area and determine the most probable minimum value of this parameter. In future, the approaches used, in combination with the field research, will contribute to the improvement of remote decryption methods.