红河流域极端水文事件时空变化及其驱动机制研究

The detection and attribution of observed variations in hydrological factors are major issues in climate change and water sicence research, how to separate the contribution of climate change and human activities on the variations of hydrological factors become the international challenging problems. Red River is an important international river in China and Southeast Asia. Under the superposed effect of monsoon, range-gorge topography and human activities, the variation of hydrological factors are very complex. Especially frequent occurrence of extreme hydrological events in recent years, have caused enormous socio-economic losses and threatening the water security, which have attracted ample attention among the upstream and downstream countries. The objectives of this proposal are to investigate the spatial and temporal variations of extreme hydrological events and reveal their driving mechanism in the Red River basin. In order to achieve the objectives, the multi-source data (including the longterm meteorological and hydrological observation data, remote sensing data) and multi-technique (time series analysis, probability statistics analysis, GIS and distributed hydrological model) are used in the study. Firstly, analysis are conducted on the spatial and temporal variation of extreme hydrological events (floods and low flows are considered) in the past 50 years. Secondly, the relationships between key driving factors (rianfall, land use change and cascade hydropower development) and extreme hydrological events are explored. Finally, based on the distributed hydrological model, the influence of climate change and human activity on extreme hydrological events are quantitatively assessed. This project is considered to be a contribution for the studies on hydrological process over plateaus in Southwest China, at the same time, the outcome will provide a scientific basis for water safety regulation, flood and drought disaster reduction in the Red River basin.

水文要素变化的检测与归因是国际上气候变化与水科学研究的重要内容，分离气候变化和人类活动对水文要素变异的贡献是当前研究的热点和难点。红河是我国与东南亚重要的国际河流，受季风驱动、岭谷地形和人类活动的综合影响，流域水文要素时空分异复杂。尤其是近年来极端水文事件频繁发生，已造成巨大的社会经济损失，并威胁流域水安全，成为上下游国家关注的焦点。本项目将基于长序列的水文、气象观测数据，结合遥感信息、野外调查等，判识流域极端水文事件（洪水/枯水）的时空变化特征，明晰关键驱动因子（降水、流域土地利用和梯级水电开发）与极端水文事件变化的关联，在此基础上采用分布式水文模型，定量分析气候变化和人类活动对径流（洪水/枯水极值）的影响，揭示极端水文事件变化的驱动机制，丰富西南高原山地流域水文过程变化研究，为流域水安全调控、洪旱灾害防治等提供科学依据。

水文要素变化的检测与归因是国际上气候变化与水科学研究的重要内容。红河作为重要的国际河流，流域水文过程受季风驱动、岭谷地形和人类活动的综合影响，时空分异复杂。近年来极端水文事件频发已造成巨大的社会经济损失，并威胁流域水安全，成为上下游国家关注的焦点。本项目主要内容为判识红河流域极端水文事件的时空变化特征，明晰关键驱动因子与极端水文事件变化的关联，揭示气候变化和人类活动对极端水文事件变化的驱动机制。主要成果：（1）采用极端降水指数、标准化降水-蒸发指数和水文极值指标，阐明近50年来流域极端降水、气象干旱以及极端径流的时空变化特征；（2）厘清流域水文干旱对气象干旱的响应、流域土地利用变化的径流效应以及梯级水电开发对下游水文情势的影响；（3）利用水文敏感性分析、气候弹性系数法以及水文模型模拟方法，估算出气候变化和人类活动对径流变化的贡献；（4）采用流域水文模型定量分析了不同气候、人类活动情景对洪水/枯水流量的影响。项目研究结果为红河流域跨境水资源管理提供科学依据。本研究发表学术论文7篇（SCI收录3篇，中文核心4篇），培养研究生4名，1名毕业，3名在读。