长江上游六流域强降水面雨量特征分析

Analysis of characteristic of area rainfall in six basins of upper Yangtze River

为满足长江流域水文气象预报服务需要,利用2001～2011年气象站点逐日雨量实况资料,以长江上游岷沱江、嘉陵江、乌江、干流宜宾至重庆、干流重庆至万县、干流万县至宜昌流域强降水面雨量为研究对象,研究其频次分布、极值分布特征。结果表明:长江上游六大流域强降水面雨量出现频次具有明显的季节变化和年际变化特征;冬季频次几乎为零,夏季频次最多,春季猛增,秋季陡降;不同流域强降水面雨量等级分布差异较大、极值分布差异明显;重庆至万县、万县至宜昌两个流域月极大值明显大于其他流域,岷沱江流域月极大值明显小于其他流域。

In order to fulfill the need of hydrometeorological forecast in Yangtze River Basin,using available observation data of daily precipitation from 2001 to 2011,the area rainfall of Minjiang and Tuojiang River Basin,Jiailing River Basin,Wujiang River Basin,the mainstream from Yibin to Chongqing,Chongqing to Wanxian and Wanxian to Yichang in the upper Yangtze River are taken as research objectives,and the frequency distribution and extreme value distribution are studied.The results show that,the frequencies of area rainfall in the six basins have obvious characteristics of seasonal and annual variation,the strong precipitations are nearly zero in winter and the most in summer,and increases sharply in spring and decreases in autumn.Great differences are found in the area rainfall distribution and the extreme value distribution.The monthly maximum values of Chongqing to Wanxian and Wanxian to Yichang are larger than others＇,and the ones of Minjiang and Tuojiang River Basin is the smallest.