兰州市暴雨强度公式拟合方法研究

本文基于兰州市国家基本气象站1960~2014年降雨资料,通过直接拟合、耿贝尔分布、皮尔逊-Ⅲ型分布研究兰州市暴雨强度公式。选用芝加哥雨型来研究兰州市雨峰系数,结合暴雨强度公式确定短历时暴雨雨型。结果表明:(1)皮尔逊-Ⅲ型分布要优于耿贝尔分布和直接拟合,其调整后的兰州市暴雨公式中1年雨力参数A1为5.532mm/min,重现期调整参数c为3.198,降雨历时偏移参数b为14.92min,n为0.942,平均绝对均方差为0.036mm/min;(2)皮尔逊-Ⅲ分布能够满足不同的降雨历时以及更久的重现期。降雨历时小于90min或者重现期大于20年的暴雨模拟精确度更高,重现期在2~20a的暴雨平均绝对均方差最小为0.03mm/min。 

Study on Fitting Method for Rainstorm Intensity Formula in Lanzhou

In this paper,based on the data of raindrop from 1960 to 2014 in Lanzhou National principal station,the Direct-fitting method,Gumbel distribution function and Pearson-Ⅲ distribution function were used to study the rainstorm intensity formula. The Chicago rain pattern were used to study the rain peak coefficient,then combining with the rainstorm intensity formula,the short duration rainfall pattern is determined. The main result as following: (1) Pearson-Ⅲ distribution function is better than both Direct-fitting method and Gumbel distribution function,meanwhile the rainstorm intensity parameter A1 of 1a is 5. 532 mm/min after adjustment,the return period adjustment parameter c is 3. 198,the rainfall duration offset parameter b is 14. 92 min and the mean absolute mean square error is 0. 036 mm/min. (2) The Pearson-Ⅲ distribution function can satisfy different rainfall durations and longer reproduction period. The simulation accuracy of rainstorm of the rainfall duration less than 90 min and the return period more over 20 a is better than other situations,meanwhile the mean absolute mean square error is minutest 0. 03 mm/min of the return period ranged from 2a to 20 a.