Runoff components and the contributions of precipitation and temperature in a highly glacierized river basin in Central Asia.

Understanding the main drivers of runoff components and contributions of precipitation and temperature have important implications for water-limited inland basins, where snow and glacier melt provide essential inputs to surface runoff. To quantify the impact of temperature and precipitation changes on river runoff in the Tarim River basin (TRB), the Hydrologiska Byrans Vattenbalansavdelning (HBV)-light model, which contains a glacier routine process, was applied to analyze the change in runoff composition. Runoff in the headstream parts of the TRB was more sensitive to temperature than to precipitation. In the TRB, overall, rainfall generated 41.22% of the total runoff, while snow and glacier meltwater generated 20.72% and 38.06%, respectively. These values indicate that temperature exerted more major effects on runoff than did precipitation. Runoff compositions were different in the various subbasins and may have been caused by different glacier coverages. The runoff volumes generated by rainfall, snowmelt, glacier melt was almost equal in the Aksu River subbasin. In the Yarkand and Hotan River subbasins, glacier meltwater was the main supplier of runoff, accounting for 46.72% and 58.73%, respectively. In the Kaidu-Kongque River subbasin, 80.86% was fed by rainfall and 19.14% was fed by snowmelt. In the TRB, runoff generated by rainfall was the dominant component in spring, autumn, winter, while glacier melt runoff was the dominant component in summer. Runoff in the TRB significantly increased during 1961–2016; additionally, 56.49% of the increase in runoff was contributed by temperature changes, and 43.51% was contributed by precipitation changes. In spring, the runoff increase in the TRB was mainly caused by the precipitation increase, opposite result in summer and autumn. Contribution of temperature was negative in winter. Our findings have important implications for water resource management in high mountainous regions and for similar river basins in which melting glaciers strongly impact the hydrological cycle. [ABSTRACT FROM AUTHOR]