Study on climate change and hydrological response characteristics on northern slope of Kunlun Mountains

Abstract

[Objective] Due to the complexity of high-altitude environments and the combined effects of climate change and human activities, the mechanisms of runoff variations on the northern slope of the Kunlun Mountains have become one of the core challenges in current hydrological research in arid regions. The coordinated evolution patterns of climatic and hydrological processes on the northern slope of the Kunlun Mountains(covering Hotan River, Keriya River, and Cherchen River basins) from 1956 to 2023, as well as their underlying influencing factors, are investigated, aiming to provide decision-making support for the sustainable management and scientific allocation of water resources in cold and arid regions. [Methods] Based on high-resolution meteorological and hydrological databases, and combining methods including linear regression analysis, moving average analysis, and anomaly analysis, the long-term trends, spatial clustering, and driving mechanisms of regional temperature, precipitation, and runoff were revealed. [Results] The results indicated that(1) the region showed significant accelerated warming, with a warming rate of 0.313~0.375 ℃/10 years, significantly higher than the global and national average values. It was primarily driven by the elevation-dependent warming effect and the decrease in surface albedo caused by snow and ice melting.(2) Precipitation generally exhibited a linear increasing trend(1.17~11.8 mm/10 years), but due to the weakening of westerly moisture transport, precipitation in the eastern region shifted to a decreasing trend after 2020.(3) Runoff increased significantly after the 1990 s(with an increase of over 30% after 2010). Decoupling analysis based on Z-score standardization confirmed that temperature contributed far more to runoff than precipitation. Runoff primarily depended on short-term replenishment from accelerated glacial melting, showing a high degree of synchrony with temperature changes, whereas the precipitation-runoff response exhibited a lag, which might be related to groundwater storage and regulation.(4) Hydrological responses differed significantly between the eastern and western regions. The precipitation-to-runoff conversion efficiency remained stable in western river basins, whereas that in eastern river basins experienced distinct decoupling after 2020. [Conclusion] The northern slope of the Kunlun Mountains shows an extreme “temperature-controlled” response pathway, and climate change has significantly reshaped the regional hydrological patterns. Therefore, it is necessary to develop a monitoring and early warning system targeting peak glacial melting, revise water conservancy engineering standards, and optimize water resource allocation strategies, so as to cope with future runoff decline risks and ensure regional water and ecological security.

Keywords

cold and arid regions / hydrological response / Hotan River / climate change / Kunlun Mountains / glacier melting / runoff evolution / influencing factors