Fisher最优分割法在李仙江流域汛期分期中的应用

针对目前常用的汛期分期方法存在的主观性强、考虑因素单一和分期结果不确定等问题,提出利用Fisher最优分割法进行汛期分期。基于Fisher最优分割法的基本原理和应用步骤,以李仙江流域为例,选择反映汛期暴雨洪水特性的5个指标,将该流域的汛期划分成了4个分期,即前汛期为6月1日~6月30日,主汛期为7月1日~9月10日,过渡期为9月11日~10月31日,后汛期为11月1日~11月30日,并将Fisher最优分割法的汛期分期结果与数理统计法以及模糊集合分析法两种常用的汛期分期方法的分期结果进行比较。结果表明,Fisher最优分割法的分期结果不仅合理可信,而且相对于常用的汛期分期方法具有一定的优越性。

Application of Fisher Optimal Partition Method in Division of Flood Season in Lixianjiang Basin

There are some problems in division of flood season by common methods at present, such as highly subjectivity, single factor in consideration and uncertainty of the results. To solve them, Fisher optimal partition method is applied to division of flood season. Taking Lixianjiang basin as an example and selecting five indexes which could reflect the characters of rainstorm and flood in flood season, the flood season of Lixianjiang basin was divided into four stages based on the basic principle and steps of Fisher optimal partition method. The pre-flood period was from June 1 to June 30, the main flood period was from July 1 to September 10, the interim period was from September 11 to October 31 and the post-flood period was from November 1 to November 30. Finally, the division result obtained by Fisher optimal partition method was compared with that by common mathematical statistics method and fuzzy set analysis method. It is indicated that the division result by Fisher optimal partition method is reasonable and believable, and the method has quite superiority over common methods.