珠海市年雨量和年最大日雨量多年一遇的极值计算

Computation of Extreme Values of Yearly Rainfall and Annual Maximum Daily Rainfall for Return Periods of Multiple Years in Zhuhai City

用皮尔逊-III型分布分别对珠海市年雨量和年最大日雨量两种变量进行拟合,进而计算了它们在不同重现期下的极值。结果表明:珠海市50年一遇的估算年雨量和年最大日雨量分别是2 908 mm和565 mm,100年一遇的分别是3 042 mm和648 mm。用澳门和珠海的雨量历史资料验证发现:澳门在104年间出现的最大年雨量是3 041.4 mm,与珠海百年一遇估算雨量吻合;珠海平均7.2年出现一次2 500 mm以上年雨量,而该雨量的估算重现期是7.5年,亦十分接近;年最大日雨量的估算重现期则比实际重现期小些。可见拟合良好,对其不同重现期下的极值估计结果可信。

The yearly rainfall and, annual maximum daily rainfall of Zhuhai city are fit by Pearson -Ⅲ distribution, and the corresponding extreme values for different return periods were computed. The results show that ： in Zhuhai, for the 50 - year return period, the estimated extreme yearly rainfall and the maximum daily rainfall are 2 908mm and 565mm resp＇ectively, while they are 3 042mm and 648mm for 100 -year return period respectively. The maximum yearly rainfall during 104 years in Macao is 3 041.4mm,which is close to the esti- mated yearly rainfall of Zhuhai in 100 - year return period ; In Zhuhai, on the average, every 7.5 years, the yearly rainfall will exceed 2 500ram, and the estimated return period for 2 500mm rainfall is 7.2 years. Similar results were also retrieved for the annual maximum daily rainfall. So the conclusion can be drawn that Pearson - Ⅲ distribution fit quite well for the two variables in Zhuhai, and the estimation of extreme values were reasonable and reliable.