Study of Thermokarst Lake Size Distribution in the Eastern Part of the Russian Arctic Based on Combining Sentinel-2 and Kanopus-V Images

Abstract

The article is devoted to remote studies of the size distribution of thermokarst lakes in the eastern part of the Russian Arctic. The studies are carried out in the Arctic territories of the Northeastern tundra (NET) (Yakutia) and the Chukotka tundra (CT), which are relatively homogeneous areas in terms of their natural properties (referred to here as ecoregions). Remote studies of the distribution of thermokarst lakes by area are conducted using satellite images from Kanopus-V and Sentinel-2 (with spatial resolutions of 2.1 and 20 m, respectively), obtained in the summer months of 2017–2021. The lakes are interpreted using a Sentinel-2 satellite image mosaic, which provides full coverage of the study territories; Kanopus-V images at 12 test sites; and QGIS 3.22 tools. We briefly describe the method of integration (combination) of data from Kanopus-V and Sentinel-2 images for plotting synthesized histograms of lakes distribution by their sizes. This technique allows us to get histograms of lake distribution in a very wide range of their sizes from 50 to 10⁸ m² in the studied Arctic ecoregions. The histogram plots show a similar behavior in both ecoregions, manifesting itself in an increase in the number of lakes as their size decreases. It is shown that the main contribution to the number of lakes in the NET is made by much larger lakes than in the CT, which may indicate a significant difference in the geocryological conditions in different Arctic territories of the eastern part of the Russian Arctic. The degree of the lake cover of the territories is assessed. It is shown that the lake cover of the NET is 7 times higher than in the studied territories of Chukotka.