分形理论在紫坪铺水库汛期洪水分期中的应用

Application of Fractal Theory in the Stage Analysis of Flood Season in Zipingpu Reservoir

洪峰散点序列在一定尺度范围内表现出了自相似性和分形特征,可用分形理论划分洪水分期。介绍了分形理论及容量维的计算方法,并以紫坪铺站历年汛期日最大流量为系列样本进行研究,将紫坪铺水库汛期洪水划分成3个分期。结果表明,利用分形理论划分的紫坪铺水库洪水分期与成因分析法和数理统计法划分的洪水分期基本一致,但与其它两种方法相比,分形方法具有客观、受经验和人为影响较小、划分的洪水分期时间更加精确等优点,有利于在生产实际中推广应用。

The flood events have self-similarity and fractal characteristic for certain duration, the fractal theory can be used to determine the division of flood stage. The fractal theory and the computation of capacity dimension are introduced in this paper, and this calculation method were used to divide the flood stage for the Zipingpu Reservoir into three periods in terms of the maximal daily discharge in flood season of each year. The results show that the periods of Zipingpu Reservoir determined by using fractal theory are consistent with that from cause analysis and mathematical statistics methods. But compared with the other two methods, the fractal method is of objective, less affected of the experience and man made and more precise of the flood stages, and it is conducive to application in practice.