Distribution and changes of thermokarst lakes along the Qinghai-Tibet Railway from 1991 to 2022

Permafrost degradation on the Qinghai–Tibet Plateau has led to the rapid development of thermokarst lakes, but their distribution along the Qinghai-Tibet Railway (QTR) has not been fully studied. In this study, we established the Landsat, Sentinel-2A and GF-1 image datasets and a 50 km wide transect along the QTR, and used ENVI software to extract lake data. The distribution characteristics of thermokarst lakes at different distances from the QTR in 2022 were analyzed. The spatiotemporal evolution of thermokarst lakes and their relationship with climatic factors from 1991 to 2022 were examined. The results showed that, from 1991 to 2022, the number and area of thermokarst lakes in the study area increased by about 3,892 and 70.08 km 2 , respectively. It was found that climate warming and intensified precipitation are the main reasons for the increase in the number and area of thermokarst lakes in the study area. This study provides basic support for an in-depth understanding of the long-term interannual changes of the thermokarst lakes along the QTR and the maintenance of the QTR.