No 2 (2026)

This paper presents the results of detailed monitoring of temperature fields and snowpack stratigraphy during the 2025/2026 winter-spring transition. The study was conducted at the Moscow State University Meteorological Observatory. Detailed stratigraphic descriptions of the snowpack, along with measurements of snow density and temperature, were also conducted. Changes in the thickness and thermal field of the snowpack at the Moscow State University Meteorological Observatory’s site were examined. Air and snowpack temperature measurements were conducted using an autonomous automatic system. The study aimed to determine characteristic diurnal and synoptic thermal rhythms, assess the insulating role of the snowpack, and describe the snowpack’s complex stratigraphy, including numerous ice crusts and deep hoar horizons. The feasibility of using an automatic measurement system to determine snowpack thickness based on its thermal field was tested. The study was conducted at the Moscow State University Meteorological Observatory. Using an original high-resolution measuring system (5 cm increments, 30 min–4 h time resolution), snow cover temperature was recorded. Detailed stratigraphic descriptions of the snowpack, along with measurements of snow density and temperature, were also conducted. It was shown that the winter season was characterized by an abnormally late onset of stable snow cover (December 22) and subsequent extreme snow accumulation, with an absolute snow depth record for 72 years of observations (86 cm on February 26, 2026). The study demonstrates the feasibility of measuring snow cover thickness by monitoring the thermal field at Moscow State University observation sites. Air temperature and snow cover measurements were conducted using autonomous automatic systems. The studies have shown the magnitude of snow thickness and identified thermal waves penetrating the snow layer at night, allowing us to estimate temperature gradients and thermal conductivity in the snow layer, as well as determine snow thickness based on the magnitude of daily temperature fluctuations and penetrating temperature waves.

The paper examines the possibility of lithological differentiation of subaqueous permafrost based on Time-Domain Electromagnetic Method (TDEM) using the example of an area in the northwestern part of the Priyamalsky shelf of the Kara Sea. The relevance of the study is determined by the need to obtain reliable information about the structure of underwater permafrost in areas designated for the prospective development of the Arctic shelf, where the composition and structure of frozen strata directly affect engineering and geological conditions and the safety of marine infrastructure. Special attention is given to the differences in the electrical properties of frozen clay and sandy deposits, which are distinctly manifested in the geoelectrical structure of the section and allow for remote differentiation. The aim of this study is to evaluate the capabilities of the TDEM method for distinguishing subaqueous frozen strata and to verify the identified patterns based on laboratory research and engineering-geological drilling data. The work is based on factual material obtained from comprehensive marine studies conducted in 2019-2024 near the western coast of the Yamal Peninsula. The methodology includes marine work using the TDEM method, laboratory determination of the specific electrical resistance (SER) of soils in thawed and frozen states, processing of field data, and correlation of the obtained results with drilling materials. The main conclusions of the conducted research are the established differences in the SER of frozen deposits of different lithological compositions and confirmation of the possibility of their remote differentiation. It has been shown that frozen clay soils are characterized by lower SER values, typically ranging from 4.5 to 6 Ohm*m, while frozen rocks with a predominant sandy composition, on the contrary, possess substantially higher resistance values: according to direct laboratory studies, the SER can exceed 1000 Ohm*m, and in geoelectrical models, values above 15-20 Ohm*m are observed. It has also been established that sandy frozen strata are characterized by greater continuity of distribution, whereas the clayey ones are typically associated with extensive areas of cooled rock. The novelty of the research lies in justifying the applicability of the TDEM method not only for delineating the boundaries of permafrost but also for preliminary lithological interpretation of the structure of subaqueous frozen strata in the Arctic shelf conditions. The practical significance of the results is related to their potential use in engineering-geological surveys, cryogeological mapping, and assessing cryogeological risks during the development of shelf deposits.