No abstract

The purpose of this article was to compile four separate digital thematic maps of temperature and ice content of permafrost, the active layer thickness, and cryogenic processes in Yakutia as a basis for assessing changes to modern climate changes and anthropogenic disturbances. In this work, materials on permafrost were used, serving as the basis for compiling a permafrost landscape map of the Republic of Sakha (Yakutia). The maps were compiled using ArcGIS software, which supports attribute table mapping. The ground temperature and active layer thickness maps reflected landscape zonality and regional differences. Peculiarities of genetic types of Quaternary deposits and climatic conditions reflected the ice content of surface sediments and cryogenic process distribution maps. One of the most common is ground temperatures from −2.1 to −4.0 °C, which were found to occupy about 37.4% of the territory of Yakutia. More than half of the region was found to be occupied by permafrost landscapes with a limited thickness of the active layer up to 1.1 m. Ice-rich permafrost (more than 0.4 in ice content) was found to be typical for about 40% of the territory. Thermokarst is the most hazardous process that occurs in half of Yakutia.

Thermokarst is a typical process that indicates widespread permafrost degradation in yedoma landscapes. The Lena-Aldan interfluvial area in Central Yakutia in eastern Siberia is now facing extensive landscape changes with surface subsidence due to thermokarst development during the past few decades. To clarify the spatial extent and rate of subsidence, multiple spatial datasets, including GIS and remote sensing observations, were used to analyze the Churapcha rural locality, which has a typical yedoma landscape in Central Yakutia. Land cover classification maps for 1945 and 2009 provide basic information on anthropogenic disturbance to the natural landscape of boreal forest and dry grassland. Interferometric synthetic aperture radar (InSAR) with ALOS-2/PALSAR-2 data revealed activated surface subsidence of 2 cm/yr in the disturbed area, comprising mainly abandoned agricultural fields. Remote sensing with an unmanned aerial system also provided high-resolution information on polygonal relief formed by thermokarst development at a disused airfield where InSAR analysis exhibited extensive subsidence. It is worth noting that some historically deforested areas have likely recovered to the original landscape without further thermokarst development. Spatial information on historical land-use change is helpful because most areas with thermokarst development correspond to locations where land was used by humans in the past. Going forward, the integrated analysis of geospatial information will be essential for assessing permafrost degradation.