气候变化对江河源区水循环的影响

Effects of Climate Change on Water Cycle in the Source Region of the Yangtze and Yellow Rivers

通过系统梳理(长)江(黄)河源区水循环要素的变化,发现近60年来的持续变暖加剧了冰川、冻土、积雪的融化,增加了源区径流量,调整了径流的季节配置;冻土退化和近期湖泊扩张与植被覆盖的改善,陆地水储量增加的同时,陆面蒸散发作用加强。这些变化特征显示江河源区的水循环速率加快,并对地表水资源和生态环境产生了重要的影响。在生态整体趋好的背景下,江河源区因冰川退缩、冻土退化等引起的沙漠化加剧、土壤侵蚀作用增强、河流输沙量提高和局部生态退化同时发生,江河源尤其是黄河源水源涵养整体功能尚未得到有效修复,部分区域生态环境恶化的风险依然较大。

The changes ofsurface water cycle in the source region of the Yangtze River and Yellow River were reviewed.We found that climate warming in the past 60 years has accelerated the melting of glaciers,permafrost and snow cover,and resulted in the increase of runoff as well as its change in seasonal configuration.With the degradation of permafrost and the recent expansion of lakes and improvement of vegetation,land evapotranspiration has been strengthened while land water reserves have increased.These changes indicate that the water cycle in the source area is accelerating and have an important impact on the surface water resources and ecological environment.In the context of the overall ecological improvement,desertification,soil erosion,increased river sediment transport and partial ecological degradation are occurring simultaneously in the source areas due to glacier retreat and permafrost degradation.The overall water conservation function of river sources,especially the Yellow Riversource,has not been effectively restored,and the risk of ecological environment deterioration in some areasisstill high.