【摘要】 基于湖南省洪涝标准,对衡阳9个测站近60a逐日降水统计,获得历年洪涝出现时段、过程雨量等基本数据,再进行洪涝不同时域变化分析,运用小波分析其变化周期,统计不同时间组合洪涝频次与农作物受灾面积百分比的相关性,分析洪涝对后期农业干旱影响。结果表明:衡阳低海拔区与南岳山洪涝频次存在明显差异,低海拔区洪涝频次为0.37次/a,南岳山为1.38次/a,是低海拔区近4倍; 1970、1980年代洪涝普遍偏少,洪涝偏多主要出现在1990年代;南岳山与低海拔区洪涝存在结构性差异,南岳山中、重度洪涝居多,低海拔区则以轻度洪涝为主;衡阳3—11月均可能出现洪涝,洪涝等级越低时间跨度越大,6月洪涝频次最大,是衡阳防汛重要时段。南岳山洪涝雨量9月最大,低海拔区7月最大; 4—7月洪涝发生频次与后期农业干旱反相关性最好,7月降水对衡阳后期农业干旱影响极为关键,降水偏少则后期农业干旱频次将明显增加。更多还原

【Abstract】 Based on flood standard in Hunan province,we counted the daily precipitation data of nine meteorological observation stations in Hengyang nearly 60 years,and obtained the basic data such as the time of floods and the rainfall in the course of floods etc.over the years.Then basing the change of flood in different time domain,we analyzed the change cycle by wavelet analysis,and calculated the correlation between the flood frequency of different time combinations and the percentage of the area of flood-affected crops to study the influence of flood on later droughts.As the results show,the flood frequency in Nanyue Mountain is 1.38 times/a,which is nearly four times that in low altitude area(0.37 times/a).The floods were relatively less in the 1970 s and 1980 s and more in the 1990 s.The floods have structural differences between Nanyue Mountain and low-altitude areas,with Nanyue Mountain having more moderate and severe floods and low altitude areas suffering mainly light ones.Hengyang may be hit by floods from March to November,and the lower the flood level,the longer the time span.The flood frequency in June is the highest,which makes June an important period of flood control in Hengyang.The flood rainfall in Nanyue Mountain is the largest in September,and that in low altitude area in July.The frequency of flood from April to July has the best inverse correlation with later droughts,and the precipitation in July is very critical to later droughts in Hengyang.If the precipitation is low,the frequency of agricultural drought will increase obviously.更多还原