长江上游中小洪水雨洪特征分析

为了从气象学角度揭示中小洪水的形成机理，将降雨与中小洪水结合起来展开分析。利用1981~2012年国家气象站逐日雨量和长江上游主要河段及干支流控制站日平均流量资料，结合三峡水库调度运行特征，采用自定义条件筛选出了长江上游中小洪水过程，并从中小洪水的分布特征、雨洪特征两方面进行研究。结果表明：自定义筛选条件合理可行；中小洪水呈逐渐减少的趋势；洪水主要集中在6~9月的汛期，三峡水库消落期无中小洪水出现；6个流域（区间）6月中小洪水过程平均面雨量自西向东增加。

Analysis of rainfall flood characteristics of small-medium floods in upper Yangtze River

To disclose the formation mechanism of small-medium rainfall flood from the perspective of synoptic meteorology, the two are combined in the analysis. Based on the daily rainfall data of meteorological stations and daily-mean-discharge data of the main control stations on the mainstream and tributaries of the Yangtze River from 1981 to 2012, by consideration of the Three Gorges Reservoir operation, we selected the small-medium floods in the upper Yangtze River by self-defined conditions. The analysis of the distributuion of small-medium flood and rainfall flood characteristics shows that the self-defined conditions are reasonable; the medium and small floods decreased gradually; the floods are in June to September mostly and no flood occurs in level fall period of Three Gorges Reservoir; the areal rainfall of middle and small floods in the six major river basins (regions) in June increase are from the west to the east. 