长江上游流域暴雨洪水相似性判别指标研究

Study on similarity discriminant index of storm flood in upper reaches of Yangtze River

暴雨洪水发生演化的各个阶段之间存在一定的关联性和规律性。以长江上游流域为研究对象,将暴雨洪水指标分为降雨、洪水、时间、雨洪关系、水库、形状和初始指标7大类,共67个指标。通过整理暴雨历史洪水资料,摘录暴雨洪水过程和计算暴雨洪水特征值,结合洪量相似度、洪峰相似度、形状相似度和灰色关联度4种相似性评价方法,优选出降水量、降水历时、起涨流量和洪水涨率4个指标作为相似洪水判别指标。以113场三峡入库洪水为样本进行相似性检验,基于几场典型洪水特征值寻找的历史相似洪水之间的相似度较高,确定性系数都达到了0.9以上。结果表明,降水量、降水历时、起涨流量和洪水涨率4个指标作为相似洪水判别指标,对指导实时洪水预报具有较高的参考价值。研究成果在三峡水库以上长江上游流域进行了试验应用,在寻找历史相似洪水方面具有较好的效果。

The correlations and regularity of storm floods exist in various stages of their development.Taking the upper reach of the Yangtze River as an example,we classified 67 storm flood indexes as seven categories,including precipitation,flood,initial state indexes,time,the relationship between storm and flood,reservoir shape and process.Four indicators including total rainfall,rainfall duration,initial rising flow and flood rising rate were optimized as the similar flood discrimination indicators by collating storm flood historical data,extracting storm-flood processes and calculating their characteristic values,and combining with runoff similarity,flood peak similarity,flood process similarity and grey correlation degree.Taking 113 floods of the Three Gorges Reservoir inflow for similarity test samples,several typical floods were chosen to search the similar history floods.The results showed that there were high similarity between them and the deterministic coefficients were all above 0.9,indicating that the four indicators had highly reference value to guide the real-time flood forecasting.The results have been applied to the upper reach of the Yangtze River above the Three Gorges Reservoir,and it has a good effect in finding historical similar floods.