Projected glacier meltwater and river run‐off changes in the Upper Reach of the Shule River Basin, north‐eastern edge of the Tibetan Plateau

Abstract

Glacier meltwater change in the north‐eastern edge of the Tibetan Plateau is greatly important for the projection of the impact of future climate change on local water resource management. Although the glaciated area is only approximately 4% of the Upper Reach of the Shule River Basin (URSRB), the average glacier meltwater contribution to river run‐off was approximately 23.6% during the periods 1971/1972 to 2012/2013. A new glacier melting module coupled with the macroscale hydrologic Variable Infiltration Capacity model (VIC‐CAS) was adopted to simulate and project changes in the glacier meltwater and river run‐off of the URSRB forced by downscaled output of the BCC‐CSM1.1(m), CANESM2, GFDL‐CM3, and IPSL‐CM5A‐MR models. Comparisons between the observed and simulated river run‐offs and glacier area changes during the periods 2000/2001, 2004/2006, 2008/2009, and 2012/2013 suggest that the simulation is reasonable. Due to increases in precipitation, the annual total run‐off is projected to increase by approximately 2.58–2.73 × 108 m3 in the 2050s and 0.28–1.87 × 108 m3 in the 2100s compared with run‐off in the 2010s based on the RCP2.6 (low greenhouse gas emission) and RCP4.5 (moderate greenhouse gas emission) scenarios, respectively. The contribution of glacier meltwater to river run‐off will more likely decrease to approximately 10% and less than 5% during the 2050s and 2100s, respectively.

Streamflow generation in semi‐arid, glacier‐covered, montane catchments in the upper Shule River, Qilian Mountains, northeastern Tibetan plateau

“…This result lies between the mean contributions of 17.0% in the Suli catchment and 20.6% in the Gahe catchment from EMMA (Table 4), consistent with their percentages of glacier-covered area to catchment area. Though this result is lower than that using a VIC-CAS (Variable Infiltration Capacity 4.2.0 model coupled glacier module with a dynamic glacier area scheme) model (23.6%) by Zhang et al (2019) and that using a degree-day mass balance model (>30%) by Gao et al (2011) for the same study area, it agrees reasonably well particularly if the difference in the study periods amongst and the uncertainties from these studies are considered. In addition, the discrepancy may be caused by the difference in the definition of glacier runoff.…”

Variation of Runoff and Runoff Components of the Upper Shule River in the Northeastern Qinghai–Tibet Plateau under Climate Change

“…The details of each meteorological and hydrological station are given in Table 1 and Figure 1. Since the time series of temperature and precipitation data were not consistent among meteorological and hydrological stations, the required data were fitted and unified into the same time series based on the monthly lapse rate of temperature and the monthly gradient of precipitation in the USR in this study [41]. In addition to temperature and precipitation as the basic forcing data, the forcing data of the SPHY model also included topography data of a digital elevation model (DEM), physical parameters of soil, land use data and glacier outlines and thickness.…”

“…Distributed hydrological models have an advantage in runoff segmentation because of their modular approach to hydrological processes. Common distributed hydrological models such as the VIC model [41][42][43], SWAT model [44] and SRM model [45] do not refine the segmentation of runoff components, while the spatial processes in hydrology (SPHY) model can divide the total runoff into glacier runoff (GR), snow runoff, rainfall runoff (overland flow and shallow lateral flow) and the baseflow [46,47]. The detailed segmentation of total runoff by the SPHY model is helpful to reveal the essential driving factors of long-time series runoff evolution.…”

“…The contribution of glacier meltwater to the river has been a hot issue that researchers have tried to quantify, especially with the accelerated glacier shrinking due to global warming. To address this issue, simulations of total runoff and GR based on the HBV model [48] and VIC model [41,43] have been carried out in the Upper Shule River, but these two models only separate GR from total runoff and do not distinguish total runoff in more detail, thus failing to reveal the essential driving factors of the increase in total runoff. To explore the response of hydrological processes to climate change and reveal the essential driving factors of runoff evolution in the USR, there is an urgent requirement to quantitatively assess the impact of glaciers, snowmelt and rainfall on the evolution of river runoff under climate change.…”

Tightening ecological management facilitates green development in the Qilian Mountains

“…融 水 对 径 流 的 贡 献 率 持 续 增 加 , 平 均 贡 献 率 约 为 23.6%; 未来情景模拟显示, 到21世纪末冰川融水对疏 勒河径流的贡献率将小于5% [22] , 河流类型将由最初的 "降水-冰川补给型"演变为"降水补给型"河流. 总体上, 祁连山综合科学考察以及相关的前期研 究成果 [23,24] , 即可为祁连山国家公园建设以及祁连山 六大流域的"山水林田湖草"系统保护与修复提供科学 依据、详实数据和决策支持; 也可为"丝绸之路经济 带"沿线国家流域治理提供典型案例和科学支撑.…”