为有效表征水库流域降水、径流等不确定性因素对水库汛期时间域划分的综合影响，针对基于集对分析的 汛期分期现有方法中根据人为经验确定汛期的问题，应用水库汛期时间域划分概念，提出采用减法集对势方法判 别汛期时间域划分结果，构建基于减法集对势的汛期时间域划分方法。以佛子岭水库汛期划分为例加以验证，选 择能够影响汛期划分的?5?个暴雨、洪水指标，并根据当地气候特性，进行佛子岭水库汛期时间域划分，其中汛期分 期包含前汛期、主汛期、伏旱期和后汛期 4 个分期，最后与集对分析两元和三元联系数法进行对比分析。应用结 果表明：用减法集对势法进行水库汛期时间域划分简便实用，汛期划分成果合理，与集对分析两元和三元联系数 法的分期结论相一致，能客观反映佛子岭流域暴雨洪水特性对汛期影响的态势，能直观区分非汛期和汛期的界限。 提出的减法集对势法用于汛期时间域划分合理可行，在水库汛期时间域划分中具有推广应用前景。

To effectively characterize the comprehensive influence of uncertain factors such as precipitation and runoff on the determining flood season in the reservoir basin according to experience in the existing method of distinguishing flood season staging based on set pair analysis, a subtraction based set pair situation method was proposed to discriminate the staging results by applying the concept of determining flood season.Taking the flood season staging of Foziling Reservoir as an example, five indexes of rainstorms and floods that can affect the division of flood season were selected. According to the local climate characteristics, the flood season of Foziling Reservoir can be divided into four periods such as the early flood season, the main flood season, the summer and drought season, the late flood season, and the bare flood season.Finally, it is compared with the method of two-element connection number and three-element connection number. The results show that the subtraction based set pair situation method is simple and practical for determining flood season, and the results are reasonable.It is consistent with the conclusion of the set pair analysis method of two-element connection number and three-element connection number, can objectively reflect the situation of the influence of rainstorm and flood characteristics on flood season in Foziling Reservoir, and also can intuitively distinguish the boundary between non-flood season and flood season. The subtraction set pair potential method proposed is reasonable to apply in determining the flood season of reservoirs.