天津市设计暴雨雨型的演变

利用天津市1951—2004年54年逐分钟的暴雨资料,采用Huff雨型法研究了天津市设计暴雨雨型及其年代变化。结果表明,天津市的暴雨雨峰大部分出现在降雨历时的第一和第二的四分之一时段内;对比前后27年数据得到的设计暴雨雨型,发现近年来暴雨出现了雨峰提前、雨峰峰值升高等现象,受此影响,暴雨径流出现了洪峰提前、径流总量升高的现象;即使设计暴雨在总量上没有变化,其降雨过程和雨型对防洪排涝和年径流总量控制的效果也会有相当大的影响。因此设计雨型的研究和设计暴雨一样都应当时常更新,并在工程设计中考虑降雨过程和设计雨型的变化可能带来的影响和水文效应。

Evolution of design rainfall pattern in Tianjin

Based on a 54 a(1951—2004)rainfall record of Tianjin with the resolution in minute,the Huff rainfall pattern method was used to analyze the design rainfall pattern and its variations over time.The results show that the most of the rainfall peaks appear in the first and second quarter of the rainfall duration.By comparing the rainfall patterns derived from pre-27 years and post-27 years,it shows the phenomena of the peak rainfalls moving forward and the peak values increasing;in consequence,it was found the phenomena of the peak runoff moving forward,the peak values of runoff being increased and the total volumes of runoff being increased as well.Therefore,even with no change of design rainfall,the rainfall processes and rainfall patterns would have great impacts on the flooding control and the control of annual runoff volume.Therefore,the design rainfall pattern should be updated more frequently as the design rainfall.The hydrological effects of the change of rainfall processes and rainfall patterns should be considered during the design of a construction project.