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
摘要
<p indent="0mm">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 headwater