西南河流源区1981~2020年间径流变化的南北差异及气候驱动机制  

Spatial disparity in runoff variability between Southwestern China's River Basin headwaters during 1981-2020

作　　者：龙笛[1,2,3] 李雪莹 吴业楠 崔艳红 田富强 段兴武[3,5] 徐祥德 Di Long;Xueying Li;Yenan Wu;Yanhong Cui;Fuqiang Tian;Xingwu Duan;Xiangde Xu(Department of Hydraulic Engineering,Tsinghua University,Beijing 100084,China;Key Laboratory of Hydrosphere Sciences of the Ministry of Water Resources,Tsinghua University,Beijing 100084,China;Southwest United Graduate School,Kunming 650500,China;School of Water Resources and Environment,China University of Geosciences(Beijing),Beijing 100083,China;Institute of International Rivers and Eco-security,Yunnan University,Kunming 650500,China;State Key Laboratory of Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081,China)

机构地区：[1]清华大学水利水电工程系,北京100084 [2]清华大学水利部水圈科学重点实验室,北京100084 [3]西南联合研究生院,昆明650500 [4]中国地质大学(北京)水资源与环境学院,北京100083 [5]云南大学国际河流与生态安全研究院,昆明650500 [6]中国气象科学研究院灾害天气国家重点实验室,北京100081

出　　处：《科学通报》2024年第25期3821-3830,共10页Chinese Science Bulletin

基　　金：国家自然科学基金(52325901);第二次青藏高原综合科学考察项目(2019QZKK0105)资助。

摘　　要：西南河流源区位于对气候变化极其敏感的青藏高原东南部,是中国及东南亚多个国家重要的水源地.本研究基于实测径流、再分析资料、遥感反演等多源数据,分析了过去40年(1981~2020年)西南河流源区径流变化的南北空间差异,并从大气环流和水汽含量变化两方面阐明其驱动机制.结果表明:(1)过去40年南部雅鲁藏布江和怒江源的径流突变发生于1997年,北部三江源(澜沧江、长江和黄河源)的径流突变发生于21世纪初期(2004~2007年);(2)降水是引起径流变化的主要气候因子,各流域的径流与降水的突变时间基本一致,且降水-径流相关性均高于0.8;(3)西风-季风环流改变引起青藏高原水汽输送和降水的空间变化,进一步导致源区径流的趋势在2000年左右发生反转,南部流域的径流先增后减,北部流域径流先减后增,空间上呈现南北对称变化的特征.大气环流影响下水汽含量的空间差异及降水变化,是过去40年间西南河流源区径流呈现南北分异的主要原因.Headwaters of China's southwestern river basins, including headwaters of the Yarlung Zangbo, Nujiang, Lancang,Yangtze, and Yellow river basins, are nestled in the southeastern part of the Tibetan Plateau and highly sensitive to climate change. These river basins play a pivotal role as vital freshwater sources for China and neighboring Southeast Asia countries, and have important impacts on downstream agricultural irrigation, hydropower, and ecological and environmental stability. In recent decades, the Tibetan Plateau has generally experienced a warming and wetting climate,which could alter runoff trends and variability over headwaters of China's southwestern river basins. Most previous studies explored runoff changes over a typical basin of headwaters of China's southwestern river basins, but they lack the analysis of the spatial disparities and driving mechanisms of runoff changes across the headwaters of China's southwestern river basins. Recent studies used proxy sets of paleoclimate data to extract low-frequency signals of changes in climate variables over the eastern Tibetan Plateau, and revealed some north-south symmetrical changes of hydrological variables in some historical periods. These studies implied that there could exist north-south disparities in the response of meteorological and hydrological variables to climate change over headwaters of China's southwestern river basins, but the underlying climate mechanisms need to be further investigated. In particular, over the past four decades when the Tibetan Plateau showed significant changes in regional hydrothermal conditions, there is still a lack of comprehensive understanding of spatial disparity in runoff variability between headwaters of China's southwestern river basins.This study integrates observed runoff data, reanalysis information, and remote sensing retrievals to examine the spatial disparity in runoff variability and their underlying climatic mechanisms across the headwaters of China's southwestern river basins from 1981 to 2020. We analyz

关 键 词：西南河流源区 径流变化 西风-季风环流 大气水汽 降水 

分 类 号：P333[天文地球—水文科学]