基于变化范围法的黄河头道拐站水沙变化分析

采用变化范围法（RVA法）对龙羊峡、刘家峡水库运行前后黄河头道拐水文站日均径流量和含沙量数据进行分析，量化评价水沙变化程度。在定量分析的成果上，结合Copula函数，进一步探讨了水库运行前后月水沙丰枯遭遇和同步频率的变化规律。研究结果表明，龙刘水库运行后，头道拐水文站径流量和含沙量减少，二者整体均发生中度改变，径流量整体改变度高于含沙量整体改变度；汛期内和极大值情况下水沙受影响程度较高；月水沙同步频率增加，非畅流期同步率变化显著，畅流期内同步频率大于异步频率。水库管理者可根据分析得出的水沙变化规律，针对性采取诸如桃汛期抬高库水位、汛期增加洪水脉冲等调度策略，在不增加淤积的前提下提高水库的综合效益。

Analysis on changes in flow and sediment at Toudaoguai on Yellow River using range of variability approach

This study uses the range of variability approach (RVA) to analyze the data series of average daily runoff and sediment concentration at the Toudaoguai hydrological station on the Yellow River mainstream, focusing on quantitative changes in daily runoff and sediment load caused by the joint operation of Longyangxia and Liujiaxia reservoirs. Changes in the characteristics of synchronous frequencies of monthly runoff and sediment concentration are also evaluated using two-dimensional joint distributions based on the Copula function. Results show that in the period of 1962-2010, runoff and sediment concentration were decreased to a medium extent with the change in runoff relatively more significant. And both were more affected in flood season and annual extreme conditions. In the open flow period of the river, synchronous frequencies of monthly runoff and sediment were increased and were greater than asynchronous ones. This study would help water-sediment joint operation for improving comprehensive benefits of reservoirs.