Fisher最优分割法在汛期分期中的应用

Application of Fisher optimal dissection method to flood season division

针对传统汛期分期多采用定性、统计分析方法,其结果往往带有不确定性的缺陷,介绍了Fisher最优分割法的基本原理和分割步骤。以海河流域密云水库为例,选取反映水库流域暴雨洪水季节性规律的5个指标,根据专家评判法给出各指标的权重系数,计算目标函数,进而进行汛期的分期计算。综合分析和合理性验证表明,该方法具有多指标聚类、满足时序性划分且能判断分几期较优等特点,较适用于汛期的定量分期研究。

Flood season division by conventional methods is often realized by qualitative statistical analysis, and the results are of high uncertainty. To overcome the disadvantage, the Fisher optimal dissection method as well as its basic principle and steps was introduced. With Miyun Reservoir in Haihe River Basin taken as an example, 5 indexes reflecting the seasonal change of rainstorm and flood of the reservoir region were selected, and the weight coefficients of each index were given based on specialists＇ judgmem. Then, the objective function was derived, and the flood season was divided for the reservoir region. Synthetic analysis and rationality validation show that the method is of multi-factor clustering characteristic, and it can realize time sequence division and confirm the optimal stages, therefore, the method is suitable for quantitative division of flood season.