The First Hillslope Thermokarst Invertory for the Permafrost Region of the Qilian Mountains

• Main Authors: Peng, Xiaoqing, Yang, Guangshang, Frauenfeld, Oliver W., Li, Xuanjia, Tian, Weiwei, Chen, Guanqun, Huang, Yuan, Wei, Gang, Luo, Jing, Mu, Cuicui, Niu, Fujun
• Format: Text
• Language: English
• Published: 2023
• Subjects: permafrost; Thermokarst
• Online Access: https://doi.org/10.5194/essd-2023-431; https://essd.copernicus.org/preprints/essd-2023-431/

Climate warming and anthropogenic disturbances result in permafrost degradation in cold regions, including in the Qilian Mountains. These changes lead to extensive hillslope thermokarst (HT) formation, such as retrogressive thaw slumps, active-layer detachment slides, and thermal erosion gullies. These in turn cause, e.g., degradation of local vegetation, economic losses, infrastructure damages, and threats to human safety. However, despite its importance, there is currently no thermokarst inventory for the Qilian Mountains. Through manual visual interpretation and field validation, we therefore produce the first quantification of HT features. We count a total of 1064 HT features, with 67 % located in the upper reaches of the Heihe River Basin, which encompasses ~13 % of the Qilian Mountains region. We furthermore document that 82 % of the HT was initiated in the last 10 years. The thermokarst terrain is observed primarily in areas with shallow active layer depth, on northern shaded slopes of 3–25°, with low solar radiation and moderate elevations ranging from 3200 to 4000 m. This first inventory of HT features is an important and missing piece in documenting changes on the Qinghai-Tibetan Plateau, and this new dataset also provides an important basis for further studies on, e.g., quantitative assessment losses caused by HT. The datasets are available from the National Tibetan Plateau/Third Pole Environment Data Center and can be downloaded from https://doi.org/10.11888/Cryos.tpdc.300805 (Peng and Yang, 2023).