Modeling Hydrologic Response to Climate Change and Shrinking Glaciers in the Highly Glacierized Kunma Like River Catchment, Central Tian Shan

Abstract

Arid and semiarid lowland areas of central Asia are largely dependent on fluvial water originating from the Tian Shan. Mountain glaciers contribute significantly to runoff, particularly in summer. With global warming, the total glacier area in the Kunma Like River catchment declined by 13.2% during 1990–2007. For future water resources, it is essential to quantify the responses of hydrologic processes to both climate change and shrinking glaciers in glacierized catchments, such as the headwaters of the Tarim River. Thus, a degree-day glacier melt algorithm was integrated into the macroscale hydrologic Variable Infiltration Capacity model (VIC). Good results were obtained for monthly runoff simulations in the Kunma Like River catchment, which suggest that the extended VIC has acceptable performance. Because of increased precipitation and air temperature, annual runoff in the catchment has increased by about 4.07 × 108 m3 decade−1 during 1984/85–2006/07. Under the assumption of the same climatic conditions, sensitivity analyses indicated that annual and summer river runoff volumes would decrease by 9.3% and 10.4%, respectively, for reductions in glacier area of 13.2%. The variation coefficient of annual runoff also increased because of shrinking glaciers. Runoff scenarios for warmer future climate and various deglaciation situations suggest that reductions in glacier area by >30% will likely produce less meltwater in summer and river runoff will decline. Consequently, the annual total discharge of the Kunma Like River is projected to decrease by 2.8%–19.4% in the 2050s scenario because of glacier shrinking.

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

“…In a previous study (Q. D. Zhao et al, ), an updated VIC‐CAS model was developed and successfully applied to the Aksu River Basin by coupling the glacier module with the original VIC 4.2 model. In the horizontal direction, glaciers were taken as a new land cover type for simulating the hydrological processes of glaciers.…”

“…In the horizontal direction, glaciers were taken as a new land cover type for simulating the hydrological processes of glaciers. The glacier ablation process used the degree‐day model (Q. D. Zhao et al, ). Each single glacier was taken as one subbasin, and the subbasins were then divided into different altitude zones.…”

“…On the other hand, the mechanism by which shrinking glaciers impact glacier meltwater and the further contribution of glacier meltwater run‐off to river run‐off change, especially the impact of shrunken glaciers on river run‐off, remains poorly understood. In this study, the contribution of glacier meltwater to river run‐off in the URSRB was assessed and projected by adopting the latest Variable Infiltration Capacity (VIC) 4.2.0 model coupled glacier module with a dynamic glacier area scheme (hereinafter referred to as VIC‐CAS; Q. D. Zhao et al, , ). The goals in this work included (a) assessing the impact of glacier change on the contribution of glacier meltwater run‐off to river run‐off from 1971 to 2012; (b) projecting the potential changes of glacier meltwater run‐off and river run‐off under the climate change scenarios RCP2.6 (low greenhouse gas emission) and RCP4.5 (moderate greenhouse gas emission), forced by downscaled climate data from four global climate models (GCMs; BCC‐CSM1.1(m), CANESM2, GFDL‐CM3, and IPSL‐CM5A‐MR); and (c) analysing the potential impact of glacier area change on the contribution of glacier meltwater run‐off on future river run‐off.…”

Review article: Hydrological modeling in glacierized catchments of central Asia – status and challenges

“…Zhao et al (2013Zhao et al ( , 2015 For the Kumalike River and the Toxkan River, the runoff has increased 13.6 and 44.9 % during 1970-2007, and 94.5 and 100 % of the increases were attributed by precipitation increase.…”

“…Zhao et al (2015) integrated a degree-day glacier melt algorithm into a macroscale hydrologic model (VIC) and indicated that annual and summer runoff would decrease by 9.3 and 10.4 %, respectively, for reductions in glacier areas of 13.2 % in the Y. Chen et al: Hydrological modeling in glacierized catchments of central Asia Kumalike River basin.…”