Abstract: In traditional fuzzy set analysis of flood season staging, the identification of interval and threshold of flood season is strong subjectivity, and in the meantime, only single factor is considered. In view of these problems, an improved fuzzy set analysis method is proposed. Index weights are calculated by using the variation coefficient method, and then all the indexes in every ten days are combined to obtain a comprehensive index to replace the original single indicator. Subsequently, the membership degree is calculated by fuzzy set analysis method, and flood season and non-flood season are divided. Finally, flood season staging is completed by searching the change point through the mean shift point method. The staging result of the improved fuzzy set analysis is generally consistent with those of mathematical statistics method and traditional fuzzy set analysis method. The improved fuzzy set analysis method proposed in this paper is proved to be of high applicability.

Key words: improved fuzzy set analysis method, variation coefficient method, mean shift point analysis, flood season staging, Wucheng reservoir