杭州市城市暴雨雨型分析研究

Analysis and Study of Rainstorm Pattern in Hangzhou

基于1971-2018年杭州国家基准气候站及2008-2019年杭州地区17个中尺度自动气象站逐分钟降水数据,统计分析了杭州市区不同时段下自然降雨过程样本的降雨雨型特征,采用年最大值降水数据,推求杭州市暴雨强度公式,并利用2种雨型方法对杭州市暴雨雨型进行设计。结果表明:杭州30 min降雨场次以第Ⅲ类单峰雨型为主,其他降雨场次以第Ⅰ类单峰雨型为主,不同时段降雨过程在2000年后发生较为集中;杭州暴雨强度公式宜宜采用检验精度最高的耿贝尔型最小二乘法计算公式;利用芝加哥雨型法与Pilgrim&Cordery法设计杭州市暴雨雨型,雨型分布趋势较为一致,整体来看,Pilgrim&Cordery雨型法雨峰位置更靠前,芝加哥雨型法设计雨量分布更为集中;结合加密自动气象站资料分析,受地形和局地小气候影响,杭州市暴雨空间分布特征存在一定的差异性,但杭州国家基准气候站仍具有较好的代表性。

The rainfall pattern characteristics of natural rainfall process samples in Hangzhou city with different durations were statistically analyzed by the minute precipitation data of the Hangzhou National Reference Climatic Station from 1971 to 2018 and the 17 mesoscale automatic weather stations in Hangzhou from 2008 to 2019.Based on the annual maximum rainfall data,the Hangzhou rainstorm intensity formula was calculated.And two rain pattern methods were used to design the rainstorm pattern in Hangzhou.The results show that the 30-min rainfall pattern in Hangzhou is mainly dominated by the type III single-peak rain pattern,and the other rainfall events are the type I single-peak rain pattern.Mainly,rainfall processes of different durations occur more after 2000.Moreover,the Hangzhou rainstorm intensity formula is easy to adopt the most accurate Gumbel least squares formula,and Keifer&Chu rain pattern method and Pilgrim&Cordery rain pattern method are used to design the rain pattern.The rain pattern distribution trend is more consistent.Rain peak position of P&C rain pattern method is more forward,while K&C rain pattern method design rainfall is more concentrated.In addition,there are some differences in spatial distribution characteristics of rainstorm in Hangzhou,but Hangzhou National Reference Weather Station data can still be a good representative.This paper provides a scientific basis for the design of urban drainage system in Hangzhou.