Variation of Runoff and Runoff Components of the Lhasa River Basin in the Qinghai-Tibet Plateau under Climate Change

Abstract

Quantitative analysis of changes in Lhasa River runoff components was significant to local water resources management. This study constructed the spatial processes in hydrology (SPHY) model in the Lhasa River Basin and optimized the model’s parameters using the hydrograph partitioning curves (HPC) method. The Lhasa River Basin’s precipitation and temperature were forecasted for 2020 to 2100 using the statistical downscaling model (SDSM) and two scenarios from the fifth generation of the Canadian earth system model (CanESM5) dataset, shared socioeconomic pathways 1-2.6 (SSP1-2.6) and shared socioeconomic pathways 2-4.5 (SSP2-4.5). This study analyzed the potential changes in Lhasa River runoff and components based on the future climate. The results showed that the Lhasa River runoff from 2010 to 2019 was composed of snowmelt runoff, glacier melt runoff, rainfall runoff, and baseflow, with the proportions of 15.57, 6.19, 49.98, and 28.26%, respectively. From 2020 to 2100, under the SSP1-2.6 scenario, the precipitation and average temperature increased by 0.76mm and 0.08 °C per decade. Under the SSP2-4.5 scenario, the increasing rate was 3.57 mm and 0.25 °C per decade. Due to the temperature increase, snowmelt and glacier melt runoff showed a decreasing trend. The decline rate of total runoff was 0.31 m3/s per year under the SSP1-2.6 scenario due to the decrease in baseflow. Under the SSP2-4.5 scenario, total runoff and rainfall runoff showed a clear increasing trend at an average rate of 1.13 and 1.16 m3/s per year, respectively, related to the significant increase in precipitation. These conclusions suggested that climate change significantly impacted the Lhasa River’s total runoff and runoff components.

Climate Change and Hydrological Response in the Ranwu Lake Basin of Southeastern Tibet Plateau

“…Users can select required modules according to their needs by closing unnecessary hydrological process modules to reduce running time and input data volume. Many studies on the Tibet Plateau have shown that the model can simulate high-altitude glacier-fed river hydrological processes very well [6,30,31,55].…”

“…After its release, the SDSM has been widely applied globally, especially in water resource management and natural disaster prediction analysis [59]. Its application on the Qinghai-Tibet Plateau indicates that the model can provide good predictions of future climate scenarios in areas such as temperature, precipitation, and evapotranspiration [55,60,61].…”