Home – Home – Jornals – Earth’s Cryosphere 2025 number 1

In the Arctic zone, the current rise in air temperatures is much faster than in the central part of Russia. This leads to an increase in the temperature of frozen ground of the foundations of buildings and engineering structures, a decrease in their bearing capacity, and an increasing risk of their destruction. At the same time, the temperature regime of frozen ground in the city depends on many factors (microclimatic features, composition and properties of soils, technogenic influence, maintenance practices). In 2022, as part of the program to create an element of a unified system for monitoring the state of permafrost in the municipality of the city of Norilsk and the Taimyr Dolgano-Nenets municipal district, the Polar Division of PJSC MMC Norilsk Nickel began a program for constructing deep boreholes in the territory of the company’s responsibility both in the natural environment (as part of the background permafrost monitoring) and the city. This article aims to assess the dynamics of the temperature regime of permafrost in the center of Norilsk. Archival materials (since 1959) and the results of geotechnical surveys conducted in Norilsk to study the geological structure, composition, and properties of frozen rocks have been analyzed, and monitoring measurements in a new thermometric borehole drilled to replace the previous one, have begun. The data obtained indicate a significant change in the geocryological conditions in the city. Over the past 65 years (from 1959 to 2024), the ground temperature at a depth of 10 m in the area of the deep thermometric borehole increased by 4.3 °C. Significant temperature fluctuations have been recorded down to a depth of 90 meters, and further down the section to a depth of 200 meters the temperature has changed by an average of 0.3 °C.

The conditions of ice cover formation in the Sharapov Shar Lagoon of the Kara Sea and its role in sediment freezing at the fast ice/bottom contact zone are considered. Based on field measurements, remote sensing data, and calculations, characteristic periods of the formation and destruction of the ice cover and its thickness over the past 46 years have been analyzed. It is shown that fast ice in the lagoon is observed for an average of 252 days a year; the ice thickness by the end of winter averages 139 cm and can exceed 160 cm in some winters. The base of sea ice is in contact with the bottom within a significant part of the lagoon: 49 % of the area in mild winters and 60 % in severe winters. Numerical modeling indicates that at sea depths of more than 0.9 m, a seasonally frozen layer with a thickness of up to 0.8 m for loamy soils and 1.2 m for sandy soils is formed under the fast ice in winter and completely thaws in summer. Calculations have also shown that in the 20th century, there were conditions favorable for permafrost formation in the zone where sea ice is frozen to the bottom. The formation of permafrost was possible at depths of up to 90 cm. In the 21st century, rising air temperatures and increasing ice-free period lead to permafrost degradation. Under modern conditions of global warming, sandy sediments can remain in a frozen state at sea depths of up to 0.7 m; clayey sediments - up to 0.3 m.

The regularities of the new formation of frozen ground near the southern boundary of permafrost against the background of a positive climate trend and permafrost degradation are considered. The new formation of permafrost against the background of long-term thawing of frozen ground is considered a paragenetic process. The spatial heterogeneity of frost heaving and thawing of soils leads to the formation of local irregularities within initially flat hydromorphic areas, where conditions become favorable for the new formation of frozen ground. Even minor altitudinal differentiation of the original surface (0.05-0.20 m) can radically change geocryological conditions and form fairly low-temperature permafrost. Thus, new frozen ground formation can occur against the background of general climate warming and permafrost degradation.

The article provides an assessment of the distribution of suprapermafrost subaerial aquifer taliks and their influence on the processes of runoff formation of two small rivers, Shestakovka and Markhinka, whose catchments are similar in area and are located near the city of Yakutsk in the continuous permafrost zone. The percent of taliks under pine forests in the Shestakovka River basin reaches 23 %; in the entire basin, 9.5 %. Under pine forests of the Markhinka River basin, taliks are not developed. The decisive role of suprapermafrost subaerial aquiferous taliks in the formation of low-water river flow in summer and autumn, as well as in the dynamics of autumn freezing of watercourses, is shown. During the summer low-water period, the Shestakovka River flow is maintained due to the discharge of groundwater from taliks and the deep active layer in pine forests. During the period of autumn-winter freezing, channel and slope aufeis are formed due to the cryogenic squeezing of groundwater from taliks and the deep active layer upon its freezing from the surface. These aufeis serve as an additional source of river water during spring floods. In the absence of taliks in the Markhinka River basin, the flow usually stops at the end of the spring flood; in summer, the river is a chain of hydraulically unconnected expansions; in autumn, it freezes and has no discharge.

This work aims to study the quantitative transformation of dissolved organic matter into CO₂ in ground ice samples collected from typical exposures of the Russian Arctic under conditions of an incubation experiment. The CO₂ emission during incubation has two peaks, the first being associated with the utilization of organic carbon dissolved in ground ice; and the second, with the mobilization of organic matter from the solid fraction of melted ground ice. Melted ice samples are characterized by high values of biodegradable dissolved organic carbon (> 65 %) and a significant positive correlation (R² = 0.82) between the values of cumulative CO₂ emission and biodegradable dissolved organic carbon. Our data indicate a high potential for ground ice to be a source of labile carbon in the ecosystem under thermodenudation.

The possibilities of using the results of permafrost temperature measurements for a short-term forecast of permafrost temperature regime by the extrapolation method and assessment of the stability of the pile foundation on the basis of this forecast are considered. The soil temperature has been monitored over the entire depth of the pile foundation, including one temperature sensor located under the lower end of the pile. The processing of the results of temperature measurements has been carried out according to the outlined methodology using three computer programs, links to which on the Internet are given in this article.

On August 19, 2024, Igor Vladimirovich Klimovsky, a famous Russian permafrost scientist, leading researcher at the Melnikov Permafrost Institute of the Siberian Branch of the Russian Academy of Sciences, PhD in Geographical Sciences, author of major monographs and maps on permafrost, as well as historical and biographical books about permafrost researchers, celebrated his 90th birthday.