摘要: 东江流域肩负着给珠三角及其周边城市与香港供水的重要任务，水文干旱特征的研究对于东江流域供水的不确定性及可持续性研究具有重要意义。基于此，本文利用Copula函数及第二重现期等方法对东江流域4个水文站1975~2009年的日流量数据进行了分析。研究结果表明，在东江流域，同时发生较高干旱强度与较长历时的干旱事件的风险由上游向下游逐渐减小；而发生较高干旱强度或较长干旱历时的干旱事件风险在上游最小，随着干旱强度或历时增大到一定程度，下游的风险相对降低。在进行水资源管理时，应将流域作为一个整体，全面考虑水文干旱风险在东江流域上中下游的异同，该文的研究对于东江流域水资源管理具有重要理论与现实意义。
Abstract:
Variations of hydrological droughts largely decide the variability and availability of water resources of a river basin. The EastRiver basinbears the heavy responsibility for water supply for the megacities within the Pearl River Delta region and those in the vicinity of the Pearl River Delta such as Shenzhen andHong Kong. About 80% of the water consumption of Hong Kong has to be satisfied by the water supply from theEast River. In this case, the sustainable water supply from theEastRiver basinwill be greatly significant for the regional social stability. In this study, statistical behaviors and risks of the hydrological droughts of the East River basin are evaluated using copula functions and the secondary return periods based on the daily streamflow data covering the period of 1975-2009. The research results indicate that the hydrological droughts of high drought severity and long duration are subjected to the decreasing risks from the upper to the lower East River basin. However, the droughts of higher severity or long duration are subjected to the lower risk in the upperEastRiver basinwhen compared to those in the lowerEastRiver basin. Water resources management of theEastRiver basinshould be integrated by taking theEastRiver basinas a whole. And the results of this study will provide theoretical and scientific grounds for the basin-scale water resources management.