Permafrost is currently analysed by reviewing temperatures at different layers compared with air and ground surface temperatures, depth of freezing and thawing, as well as overall coverage including snow and vegetation. Mean annual air temperature (MAAT) and mean annual ground temperatures (MAGT) are a widely used source of analysis with the practical measurements being completed at monitoring sites. These observation stations across the regions are used to monitor changes, often between 30 – 50 years. With global warming reducing permafrost, the levels of observation have increased.
The researchers looked specifically at the western Russian Arctic, with analysis from 13 active layer monitoring sites and 64 boreholes. The overall MAAT increased by 1.4ºC between 1961 and 1990, both frost and thaw indexes are above climatic noms resulting in 10% increase of warming in both cold and warm seasons.
They found that between 1991 – 2020, the spatially averaged MAAT also increased by 0.052ºC annually which is a higher rate than most non-Arctic areas. Atmospheric precipitation also affected the increase in temperature and thawing of permafrost, approximately 50-100mm higher than previous climatic measurements, even higher on the Arctic coast which is also affected by maritime climatic conditions. Snow cover increased by 1.8 cm annually which warms ground temperature which in turn degrades permafrost.
They found increased moisture level in upper soil levels, increases heat consumption, with the greatest changes in forest tundra and the northern taiga. In permafrost layers on peatlands, there is now an all year round thawing layer, on some sandy tundra areas, thawing increased to 120cm, some areas adjacent to new gas exploration sites. Generally they found lower ice content in sandy areas compared to peatlands. Overall MAGT is increasing but the overall range of temperatures across the western Russian Arctic is narrowing.
the rates of ground warming are higher for the regions with cold continuous permafrost and smaller for the warm permafrost areas. As a result, the overall range of the MAGT for different landscapes is reducing.Markova et al., 2022
They also used regional maps and GIS to analyse trends, which they then used to create dynamic maps showing the distribution and range of changes in the permafrost landscape. They recorded the presence of increased taliks (unfrozen ground areas e.g. the Siberian craters) across the regions. Overall they confirm that partial degradation of permafrost in WRA and Sub-Arctic has already begun.
Malkova G, Drozdov D, Vasiliev A, Gravis A, Kraev G, Korostelev Y, Nikitin K, Orekhov P, Ponomareva O, Romanovsky V, Sadurtdinov M, Shein A, Skvortsov A, Sudakova M, Tsarev A. Spatial and Temporal Variability of Permafrost in the Western Part of the Russian Arctic. Energies. 2022; 15(7):2311. https://doi.org/10.3390/en150723