Sensitivities of hydrological processes under climate warming and Landuse/landcover change in the Lhasa basin, Tibetan plateau

Abstract

Study Region: The Lhasa River Basin (LRB) on the Tibetan Plateau.Study Focus: This study assessed the influence of climate change and landuse/landcover (LULC) change on hydrological processes using the water balancing simulation model (WaSiM). We used multiple data sources in a multi-objective calibration and validation approach, such as streamflow, snow cover, and glacier inventory, to minimize the uncertainties in the simulation results. Heat transfer in the soil was implemented in this study, which is crucial for permafrost regions.New Hydrological Insights for the Region: The results revealed spatiotemporal variation of precipitation change induced by climate warming in the last few decades. Runoff, actual evapotranspiration, and glacier melt are experiencing an increased trend. Meanwhile, decreased trends are signaled for snowmelt and water storage changes. Snowmelt showed an earlier peak that changed from June to May, which, combined with increased rainfall, resulted in an earlier peak of runoff in the basin. Rainfall is the main factor affecting runoff generation in LRB, while snowmelt and storage change are driven by the amount of snowfall, and actual evapotranspiration and glacier melt are most influenced by temperature. The annual discharge in LRB is projected to decrease, ranging from 20% to 39%, in response to the total permafrost degradation. Finally, the apparent variations in LULC exhibited in this study reveal a variety of water cycle and hydrological implications.