EVALUATION OF CLIMATE-INDUCED EVOLUTION OF THE MORPHOLOGICAL STRUCTURE OF THERMOKARST PLAINS IN THE PERMAFROST ZONE USING REMOTE SENSING DATA

Abstract

Changing geocryological conditions and the permafrost zone landscape due to climate change is currently an acute issue actively studied by many researchers. However, insufficient attention is paid to the change in the morphological structure and quantitative analysis. The aim of the study was a quantitative analysis of morphological structure of the thermokarst plains with fluvial erosion and lacustrine thermokarst plains. The study was carried out based on satellite imagery, including archival images of Corona with a resolution of 3–12 m/pix, for 1961–1979, and a set of modern high-resolution images of 0.5–2.5 m/pix for 2008–2019. Analysis of changes in the morphological structure of thermokarst plains was carried out in 9 key areas located in the zone of continuous permafrost, in the north of the West Siberian Lowland, at the mouth of the Lena River, in Eastern Siberia, on Baffin Island. Checking statistical differences between samples 1961–1979 and 2013–2019 using the Smirnov criterion revealed statistically significant differences in the distributions of lake areas of the thermokarst plains with fluvial erosion in only two sites. In one of these areas, the changes are of a smooth and integral-exponential form of the distribution of lake areas preserved. Assessment of the significance of statistical differences for 1964–1976 and 2008–2014 for the thermokarst plains revealed a significant difference for only one area. The change in the morphological structure of the thermokarst plains with fluvial erosion due to climatic changes is more intense than that of thermokarst plains; changes affected 22% of key areas versus 12% near thermokarst plains with fluvial erosion. Key areas where changes have been identified are located on the Yamal Peninsula. The resistance of morphological structures to climatic changes is higher than that of individual components of the landscape. Erosion processes are the first to respond to climatic changes, and the change in these processes leads to a change in the distribution of the areas of thermokarst lakes in thermokarst plains with fluvial erosion during the intensification of their descent and transformation into khasyreys.