Increasing Selin Co Lake Area in the Tibet Plateau with Its Moisture Cycle

Lake areas across the Tibet Plateau have been taken as the major indicator of water resources changes. However, drivers behind spatiotemporal variations of lake areas over the Tibet Plateau have remained obscure. Selin Co Lake is the largest lake in the Qinghai–Tibet Plateau. Here, we delineate the Selin Co Lake area changes during the period of 1988–2023 based on Landsat remote sensing data. We also delved into causes behind the Selin Co Lake area changes from perspectives of glacier changes and tracing water vapor sources. We identified the persistently increasing lake area of Selin Co Lake. The Selin Co Lake area reached 2462.59 km2 in 2023. We delineated the basin of Selin Co Lake and found a generally decreasing tendency of the main glaciers within the Selin Co basin. Specifically, the loss in the Geladandong Glacier area is 17.39 km2 in total and the loss in the Jiagang Glacier area is 76.42 km2. We found that the melting glaciers and precipitation within the Selin Co basin are the prime drivers behind the increasing the Selin Co Lake area. In the Selin Co basin, approximately 89.12% of the evaporation source of precipitation is propagated external to the Selin Co basin by the westerlies and the Indian monsoon. The internal hydrological circulation rate is 10.88%, while 30.61% of the moisture transportation is sourced from the ocean, and 69.39% is from the continental land. The moisture transportation from the ocean evaporation shows a significant increasing trend, which may contribute to the continued expansion of the Selin Co Lake area.