关键词:  暴雨强度公式, 皮尔逊 －Ⅲ 型, 对比分析

Abstract:

Storm intensity formula is one of the most critical criteria for the design of retention or detention facilities and drainage systems，and can directly affect their safety．In order to accommodate the increasing frequency and intensity of precipitation caused by　global climate warming，the revision of storm intensity formula is necessary． In this paper the storm intensity formula in urban of Shijiazhuang was studied based on the precipitation data during 1961－2012．The storm cases were selected by annual multisampling and maximum methods，firstly．Then，the relations among the intensity，duration and recurrence period of storm was built by Person－Ⅲ distribution analysis．And on this basis the Gauss－Newton iterative method was applied to derive the storm intensity formula． Finally，the absolute and relative standard deviations were used to assess the fitting goodness of storm intensity formula．The results showed that the accuracy of storm intensity formula derived by using annual multisampling method was higher than that derived by using annual maximum method，and it met the evaluation indexes of storm intensity formula．The storm intensity of most precipitation processes derived by new formula was bigger than that derived by the formula deduced in 1978，it got bigger and bigger with the increasing of precipitation duration，and it was consistent with the change trend of extreme precipitation events in Shijiazhuang city in recent 30 years．Therefore，it is necessary to study and revise the storm intensity formula with the accumulation of data and the expansion of city．

Key words: storm intensity formula, Person －Ⅲ distribution, comparison analysis