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澜沧江梯级开发对下游河道泥沙过程的跨境生态效应,是该国际河流跨境水资源开发及其环境效应研究中的关键问题之一．文中利用澜沧江和下湄公河上下游两个紧邻的干流水文控制站允景洪水文站和清盛水文站1987-2003年实测泥沙序列,进行含沙量月序列过程线对比以及年序列相关回归分析、因果关系检验研究．结果表明:同位于大坝下游的两站虽均受已建水库调节流量的影响,但两站的来沙响应趋势不一致,年序列线性回归拟合程度不高;时间序列Granger因果关系分析也表明了,两站泥沙除了上游的允景洪最大悬移质泥沙含量变化是下游清盛最大悬移质泥沙含量变化的原因以外,年平均、年月平均最小泥沙过程无明显因果关系．这些方面的发现,对进一步研究澜沧江电站建设对下游泥沙变化以及跨境影响的科学评价提供了新的证据．
The transboundary ecological effects of the cascade development of the Lancang River on the sediment transport in the lower reaches of the Yangtze River is one of the key issues in the study of cross-border water resources development and its environmental effects in the international rivers. In this paper, the sediment sequences from 1987 to 2003 of Yunjing Hydrometric Station and Qingshui Hydrological Station near the Lancang River and the Lower Mekong, two immediately adjacent hydrological control stations, are used to conduct the line contrast of sediment concentration monthly sequence and the regression analysis of annual series, Research on causality test. The results show that although the two stations located downstream of the dam are affected by the adjusted flow rate of the built reservoirs, the responses of the two stations to the sand are inconsistent and the linear regression fitting of the annual series is not high. The Granger causality analysis also shows that In addition, the change of maximum suspended sediment concentration in Yunjing reservoir upstream and downstream of Yunjing is the reason for the change of sediment content of the maximum suspended sediment in the downstream of Qingjing. There is no obvious causal relationship between annual average and minimum sediment concentration. These findings provide new evidence for further research on the scientific evaluation of the influence of Lancang Power Station construction on sediment change and cross-border in the downstream.