Distribution and Recurrence of Warming-Induced Retrogressive Thaw Slumps on the Central Qinghai-Tibet Plateau

Retrogressive thaw slumps (RTSs) have become a dominant geomorphic event in permafrost regions due to the modern climate change. However, the roles of topographic, vegetation, and soil factors in influencing the spatial distribution and recurrence of RTSs remain not fully understood. Here, we identified the formation and recurrence of 459 RTSs during 2008-2021 using satellite images of the central Qinghai-Tibet Plateau (Northwest of the Beiluhe Basin, 239 km(2)). We found that the topographic and environmental attributes of the RTSs exhibited strong correlations with the variation in the RTS density. The RTS-affected areas had a higher slope, elevation, relative slope position, normalized difference vegetation index, soil water content, and lower soil bulk density than other landscapes. Regarding the influence of topographic and environmental attributes on the activity status of RTSs during 2018-2020, we found that the higher slope, elevation, and soil water content were advantageous for the activity of the RTSs. The RTSs with larger sizes and presenting an elongated shape were more likely to be active. Additionally, we examined the variation of the headwall shape of RTSs based on the fractal dimension and UAV-based orthophoto. We found that the headwall shape of RTSs becomes more complicated due to the small-scale thawing of ice-rich permafrost, which may further induce subsequent thaw slumping. Higher air temperature triggers new RTSs, and increased precipitation may be responsible for the further activity of RTSs. Our findings can enhance our understanding of the development pattern and mechanism of RTSs in permafrost regions.