气候变化下高寒山区径流不同组分演化过程及机理研究——以乌鲁木齐河源流区为例

The mountainous region is an important part of the “Critical Zone” of the earth’s surface environment. Glacier and snow as major parts of solid reservoirs in mountains, strongly impacted by climate change. Understanding the composition and evolutionary processes of runoff components can provide significant basis for systematically assessing the impact of climate change on hydrological processes in alpine river basins. In this study, the headwater of Urumqi River is selected as the study area, a typical river basin in the Tianshan Mountains. Using methods by combining geography and isotope hydrology, as well as experiment and model. This study mainly focused on the key processes of “temperature/precipitation-glacier/snow-runoff” in the headwater of Urumqi River, to interpret the seasonal and interannual variations of runoff components; then based on the influence of climatic factors on runoff components to illustrate their response to climate change, and furthermore to reveal the evolutionary process and mechanism of runoff components under climate change. This study will provide scientific reference for the management and allocation of water resources in mountain basins.

山区是地表“关键地带”的重要构成部分，以冰川和积雪为主体的固态水资源储量丰富，并深受气候变化的影响。掌握径流组分解析及演化过程，是系统评估气候变化对高寒山区流域水文过程影响的基础。本项目以天山典型流域——乌鲁木齐河源流区为研究区域，采用地理学与同位素水文学相结合、模型分析与实验研究相结合的方法，以山区“气温/降水-冰川/积雪-径流”关键过程为核心，解读径流不同组分的季节和年际变化特征；基于气候因子对径流不同组分的影响，阐明径流不同组分对气候变化的响应过程，揭示气候变化下源流区径流不同组分演化过程及机理，为山区流域水资源管理与配置提供决策参考。

厘清径流组分的构成及变化是探究气候变化下流域水文过程演化机理的前提和基础，而掌握流域水文过程演化机理是评估气候变化对流域水资源影响的关键，但当前对这一问题的研究非常有限，亟待加强。本项目以天山典型流域——乌鲁木齐河源流区为研究区域，拟采用地理学与水文学相结合、模型分析与实验研究相结合的方法，以山区“气温/降水-冰川/积雪-径流”关键过程为核心，开展了该项目的研究工作，取得较为系统的研究进展，主要成果包括：收集了乌鲁木齐河流域气候数据，结合降水形式划分的双阈值模型，解读了乌鲁木齐河流域气温、降雨、降雪率的时、空及海拔等变化特征；构建了适合于乌鲁木齐河流域径流组分模拟的水文模型，分析了乌鲁木齐河源流区增温海拔依赖性特征下降雨径流和冰川融水径流的演化特征，厘清了乌鲁木齐河流域径流组分的变化特征；提出了气候变暖驱动下高寒山区流域水资源变化的研究框架，为系统解读高亚洲区域流域水资源变化特征提供了案例基础。