Spatiotemporal characteristics of surface water resources in the Tibetan plateau: Based on the produce water coefficient method considering snowmelt

The Tibetan Plateau (TP), with its widely distributed cryosphere elements and the source of 12 major rivers, is a strategic area for Asian water resource generation, storage, and migration. Because of the unique surface water resources (SWR) characteristics, multi-phase and multiple sources, the hydrological process here is extremely complex. Coupled with the lack of measured data, the SWR in the TP has not been quantified refinedly. Thus, an improved large-scale SWR assessment method was proposed based on the produce water coefficient (PWC) method considering snowmelt. It overcomes the challenge of scarcity of data on ungauged regions. As climate changes, long-sequence dynamic evaluation of SWR can be achieved refinedly. As a result, the datasets of the amount of SWR of the level 4 water resources zones (WRZ) in the TP from 1956 to 2018 were obtained by calculating the PWC and snowmelt. Then spatiotemporal characteristics of SWR in the TP were analyzed. The results showed that the annual average SWR of the TP has been increasing over the past 60 years. Affected by climate change, the SWR in the Eastern TP increased, while the SWR in the Western TP (western part of the Karakoram Mountains) decreased significantly. The findings could be beneficial for water resource security and sustainable development in Asia. This revised method, which well avoided the misestimation of classical methods, could be used to evaluate the large-scale SWR for cold and ungauged regions.