摘要
Water and sediment transport from rivers to oceans is of primary importance in global geochemical cycle.Against the background of global change,this study examines the changes in water and sediment fluxes and their drivers for 4307 large rivers worldwide(basin area!1000 km2)based on the longest available records.Here we find that 24%of the world’s large rivers experienced significant changes in water flux and 40%in sediment flux,most notably declining trends in water and sediment fluxes in Asia’s large rivers and an increasing trend in suspended sediment concentrations in the Amazon River.In particular,nine binary patterns of changes in water-sediment fluxes are interpreted in terms of climate change and human impacts.The change of precipitation is found significantly correlated to the change of water flux in 71%of the world’s large rivers,while dam operation and irrigation rather control the change of sediment flux in intensively managed catchments.Globally,the annual water flux from rivers to sea of the recent years remained stable compared with the long-time average annual value,while the sediment flux has decreased by 20.8%.
河流水沙运动是地球化学循环的重要驱动力.本研究基于全球变化背景下的长序列水沙资料,对4307条世界大河(流域面积≥1000 km^2)水-沙通量的9种变化趋势及其成因进行了系统研究.结果表明,全球24%的大河呈现显著的径流变化,但年入海通量基本保持稳定;40%的大河呈现显著的泥沙通量变化,年入海通量下降20.8%;其中,亚洲大型河流的水沙通量下降趋势及南美亚马逊河的悬移质浓度上升趋势尤为突出.总体上,71%的世界大河径流变化与降水密切相关,而泥沙通量变化受大坝运行和灌溉等人类活动影响较大.
基金
supported by the National Natural Science Foundation of China (51721006 and 91647211)
