Analysis of Thermophysical Properties of Cryolithozone Soils Using Data of the Vertical Temperature Profile Monitoring

The article presents the methods and results of the study of heat exchange changes during the transformation of the soil of the cryolithozone of the Norilsk industrial region due to anthropogenic impact. The methods are based on the numerical analysis of field measurements. The considered measurements are made in 2023 and 2024 in the two flat tundra sites, the soils of that belong to the type of cryogenic soil most typical for that terrain. The first site presents the natural condition of soil and the second one presents the technogenically transformed condition. The values of the thermal diffusivity coefficients of the studied soils were reconstructed from long-term temperature monitoring data based on the amplitude and phase methods, as well as by solving the inverse problem of heat transfer, and compared with the results of direct measurements in soil sections. The average calculated thermal diffusivity coefficients obtained by all the methods for the soil in the natural conditions have higher values, up to 35 %, compared to the field measurement data. For the transformed area, the calculation by the method based on solving the inverse heat transfer problem shows a match with the field measurement data, and the average values based on the amplitude and phase methods show higher values, by about 25 %. It was found that for the transformed soil, the thermal diffusivity is more than twice as high as for the background soil, which ultimately leads to the observed difference in the depth of soil thawing by 1.5–2 times.