长江和清江洪水遭遇风险分析

Flood encountering risk analysis for the Yangtze River and Qingjiang River

引入混合von Mises分布拟合了长江上游与清江年最大洪水发生时间的双峰特征,即夏汛和秋汛。随后应用Copula函数分别构造了两江年最大洪水发生时间及发生时间与其量级之间的联合分布,研究了最大洪水发生时间及发生量级遭遇的风险特征,计算得出两江洪水遭遇的两个峰值点7月15日和9月13日的风险率分别为0.02%和0.008%;并定量估算了7月15日两江洪峰流量达到荆江河段安全流量及最大防洪能力的遭遇风险,其最大风险率分别为6.0×10-5和5.8×10-6。最后,绘出了两江同频率洪水的日遭遇风险图和非同频率洪水在遭遇时间两个峰值点的风险图,可为三峡水库和隔河岩水库进行风险调度或补偿调度提供一定依据。

Mixed von Mises distribution was introduced to fit the bimodality characteristics of the annual maximum flood occurrence dates（AMFOD）.Copula function was used to construct the joint distribution of AMFOD between the Yangtze River and Qingjiang River and also joint distribution of AMFOD and corresponding magnitudes of these two rivers,respectively.Encountering risk of AMFOD and that of corresponding magnitudes between two rivers were analyzed.Two peak points of July 15th and September 13th were obtained with a risk of 0.02% and 0.008% respectively.Encountering risks of combination to safety flow and maximum flow on July 15th were estimated quantitatively,with the maximum risk of 6.0 × 10-5 and 5.8 × 10-6 respectively.The daily encountering risk diagrams of both equivalent and non-equivalent frequency combinations were drawed up,which can be used for risk control or provided as reference for compensational operation of the reservoirs of the Three Gorges Project and the Geheyan Project.