Hydrological response to climate change in a glacierized catchment in eastern Tien Shan, Central Asia

Abstract

Study region: The headwaters of Urumqi River basin located in eastern Tien Shan Study focus: Glacier shrinkage in recent decades has caused the volume and timing of glacier-fed streamflow to change, which in turn has significantly impacted the water supply and ecological system in the vast arid land in Central Asia and drawn wide public attention. Based on a glacio-hydrologic degree-day model, the runoff mechanisms and processes of the glacier-fed catchment are revealed. New hydrological insights for the region: The study found that about 51 % glacier coverage of the Urumqi Glacier No.1 catchment (UG1C) generates approximately 76 % glacier runoff, indicating that glacier melt comprises a significant water resource in the region. The different ways that the glacier melts in response to temperature versus precipitation on a daily scale by changing glacier mass balance can effectively stabilize streamflow, showing a strong capacity of the glacier to naturally adjust streamflow beneficially to water utilization by those downstream. Based on the sensitivity of modelled runoff to glacier change by comparing simulations using constant glacier cover that accommodated dynamic changes in glacier area, we found that the maximum volume of ice melt runoff during the past four decades appeared during the period 1996–2019, most likely around 2010.

Keywords

• Climate change
• Glacierized catchment
• Ice melt runoff
• Snowmelt runoff
• Glacio-hydrological model