南四湖流域暴雨分布特征及可能日最大降水量计算

Distributional Characteristics of Heavy Rainfall over Nansi Lake Basin and Calculation of Daily Maximum Possible Precipitation

利用南四湖流域11县市1971～2007年的暴雨资料,分析南四湖流域首次和末次暴雨的开始和结束时间以及暴雨的时空分布特征,发现南四湖流域暴雨的时空分布差异较大,但日降水极值的概率分布却有一定规律,呈Λ(x)型渐进分布。利用耿贝尔分布计算南四湖流域多年一遇的日最大降水量极值,计算的未来10年、20年、40年的日最大降水量与历史上10年、20年、40年的日最大降水量重现期基本一致,对未来50～200年的估算值也具有一定的参考价值。

Using the rainfall data of 11 counties over the Nansi Lake basin from 1971 to 2007,analyzed are the starting and ending times of the first and the last heavy rainfall over the Nansi Lake basin,as well as the temporal and spatial distributional characteristics of heavy rainfall. It is found out that there are different temporal and spatial distributions in heavy rainfall over the Nansi Lake basin. The probability of daily maximum possible precipitation exhibited a Λ（x）-typed progressive distribution. The daily maximum precipitation that happened once in certain years is estimated by using the Gumbel distribution. Estimation results show that the return periods of the estimated daily maximum precipitation of the next 10 years,20 years,40 years are basically the same as those in history,which is a good reference for the estimates of next 50 to 200 years.