Home – Home – Jornals – Earth’s Cryosphere 2026 number 4

The thickness of permafrost on Novaya Sibir Island was estimated using numerical modeling, geothermal data obtained in the 1970s, and an analysis of the region’s geological history. Because of the late onset of freezing at the subaerial stage of development during MIS 4 (75-55 ka ago) combined with prolonged marine stages in the Middle and Late Pleistocene and reduced cooling under the glacial cover during MIS 6 (190-135 ka ago), the current thermal regime of the island permafrost is nonstationary. A map showing the thickness of permafrost on Novaya Sibir Island has been compiled based on the simulation results. Permafrost with an estimated thickness ranging from 316 to 337 meters covers most of the island. The thickest permafrost (550 m) is found in the areas, where hard rocks of the basement with high thermal conductivity lie close to the surface. A reduction in permafrost thickness to 256 meters is due to the presence of brown coal layers with low thermal conductivity. The results of the study indicate that, under similar cryolithological conditions, permafrost in Novaya Sibir Island is 100-200 meters thinner than that in the coastal lowlands of northern Yakutia.

A number of controversial issues on the genesis and metamorphism of ground ice are being addressed using structural-genetic methods and modern image analysis techniques. Ancient ground ice in natural outcrops is often transformed by seasonal cryogenic processes. The aim of this study is to identify features of the ancient ground ice metamorphism under the impact of modern processes. Ground ice and host sediments were studied at two key areas - the Pur-Taz interfluve and western Yamal - in the continuous permafrost zone of Western Siberia. At the Tazovsky geocryological station, ice wedges in thick Holocene peatlands and associated new ice formations beneath the thawed and frozen active layer were studied in 2017-2019. At the Marre-Sale station in western Yamal, data on the structure of ice wedges, wedge-shaped ice, massive ice beds, and associated newly formed ice bodies in sandy, loamy sandy, and loamy substrates were obtained in 2011-2019. In the upper part of the Marre-Sale coastal bluffs, the active layer overlying permafrost contains records of seasonal and long-term variations in thawing and freezing depths. At the foot of the coastal bluff, massive ice beds overlain with thawed and frozen scree sediments and a recently buried snowpack were described. The impact of modern processes on ground ice was assessed using cryolithological methods applied to host and overlying sediments. Thin sections were prepared from oriented ice core samples preserved in the frozen state. Structural and textural features of ice bodies of different geneses - wedge ice, massive segregational ice beds, injection-segregational ice, wedge-shaped ice - were determined in thin sections using transmitted and polarized light. Superimposed structural and textural features of these ice bodies were identified in the zone of their transformation by modern processes. The study made it possible to identify and visualize macrostructure and characteristic features of the transformation of texture and structure in thin sections of different genetic types of ground ice.

To maintain the operability of capital construction facilities in the Arctic, adaptive design is used, in which weak soil foundations are cooled by ventilated underground and, if necessary, artificially frozen using seasonally operating cooling devices. The purpose of this study is to evaluate the impact of the operating mode of a ventilated underground on the state of the artificially frozen soil base of a capital construction facility using the example of an apartment building in Salekhard. The temperature regime of the soil foundation was monitored using thermometric boreholes from 2018 to October 2025. The operating mode of the ventilated underground was studied using thermistor strings installed along three transverse profiles. The velocity and temperature of air flows in the underground were determined using a Kestrel weather station throughout the entire area, quarterly, throughout the year. Based on the data obtained, maps and diagrams of temperature distribution and air flow velocity in the underground, as well as ground temperature distribution at depths of 8 and 10 m below the surface, were built using the Surfer 16 software package. As a result of the study, optimum velocities of air flows in the underground for the most efficient heat removal from the soil base were determined.

The paper presents a comparative analysis of snow density in forests and fields of plain areas of Russia obtained during snow surveys at 82 weather stations in the periods of 1966-1990 and 1991-2020. On average, snow density in forests is 5-10 % lower than in open fields, primarily due to reduced wind impact and weaker snow compaction. In some regions (western and southern European Russia, southern Siberia), the opposite relationship is observed, which is caused by microclimatic features of forest areas favoring melting-refreezing processes. The ratio of snow density in forests to that in open fields ranges from 0.82 to 1.15. No statistically significant changes in snow density for the two studied climatic periods have been detected. The results clarify the spatial differentiation of snow cover parameters depending on landscape conditions and can be used to improve heat exchange models and estimates of snow storage.

On September 16, 2026, Viktor Vasilievich Shepelev, Chief Researcher at the Melnikov Permafrost Institute of the Siberian Branch of the Russian Academy of Sciences (SB RAS), Doctor of Geology and Mineralogy, Professor, Full Member of the Academy of Sciences of the Republic of Sakha (Yakutia), Honored Scientist of the Republic of Sakha (Yakutia), and Honorary Citizen of Yakutsk, celebrates his 85th birthday. This paper presents the main achievements in his research, organizational, pedagogical, and public scientific expert activities, as well as biographical information.

This paper presents the biographical data and key achievements in the research and organizational activities of R.V. Zhang, Doctor of Engineering, Chief Researcher at the Melnikov Permafrost Institute of the Siberian Branch of the Russian Academy of Sciences (SB RAS), Honored Scientist of the Russian Federation and the Republic of Sakha (Yakutia), who celebrates his 85th birthday on September 5, 2026.