Thermokarst lake changes along the Qinghai-Tibet Highway during 1991–2020

Abstract

Thermokarst lake development significantly affects hydrologic systems, infrastructure stability and biogeochemical processes, while the spatial and temporal changes in thermokarst lakes remain largely unknown. Here, we created a thermokarst lake dataset on the Qinghai-Tibet Plateau (QTP) using a threshold-based mapping method based on Google Earth Engine (GEE) data associated with visual inspection. The dataset includes a thermokarst lake inventory on the QTP at a 10 m resolution produced from Sentinel-2A images and a multitemporal inventory along the Qinghai-Tibet Highway (QTH) from Landsat and Sentinel-2A images. We analyzed the temporal and spatial changes in thermokarst lake area and their relationships to environmental factors. Our results showed that thermokarst lakes on the QTP permafrost region covered a total area of 1572 ± 184 km2, with most of the thermokarst lakes <10,000 m2 in area. The spatial distributions of thermokarst lakes are affected by the ground thermal stability, active layer thickness, vegetation type, and ground ice content. Over the past 30 years, the number and surface area of thermokarst lakes along the QTH have increased by 58.8 % and 83.1 %, respectively, with the increase in lakes likely caused by climate warming and precipitation increasing. This study provides deep insight in the long-term interannual variations and its driving factors in thermokarst lakes along the QTH.