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宜昌市区短历时暴雨雨型特征

The analysis of the designed storm pattern over Yichang

  • 摘要: 采用宜昌市国家基本气象站1956—2013 年共58 a 的逐分钟降雨过程资料,分别利用P & C 法和芝加哥法推求宜昌市区重现期2 a 历时30、60、90、120、150、180 min 以5 min 为单位时段的设计暴雨雨型,并分析比较两种方法所得结果的差异。结果表明:利用P & C 法推求的宜昌市区各降雨历时设计暴雨雨型基本呈单峰型,历时30、60 min 设计暴雨雨型雨峰位置基本处于降雨过程的1/3 分位,而历时120、150、180 min 基本处于甚至超前于1/4 分位;利用芝加哥法推求设计的宜昌市区暴雨雨型雨峰位置基本处于甚至超前于降雨过程的1/3 分位,雨峰降雨强度虽随着历时的增加整体呈现减小—增大—减小的波动趋势,但是峰值差异较小;P & C 法和芝加哥法推求的宜昌市区短历时设计暴雨雨型都具有“单峰型、速度快、高强度、持续久”的特点,因此当短历时暴雨发生时,水利、水文、住建、防洪等部门应在第一时间做好排水排涝准备。

     

    Abstract: In this paper, fifty-eight year rainfall data of Yichang National Basic Meteorological Observing Station from 1956 to 2013 are used to investigate the designed storm pattern at Yichang by P & C and Chicago methods, which is based on the time-intervals of 5 minutes to make an analysis of storm pattern over Yichang on 30, 60, 90, 120, 150, and 180 min of 2 years return period. The results show that nearly all the designed storm pattern of all rainfall durations in Yichang by P & C method presents a single-peak pattern. The rainfall peak of the designed storm pattern on 30, 60 min is located at 1/3 over the whole rainfall period, while being1/4 on 120, 150, 180 min. The rainfall peak of the designed storm pattern by Chicago method on all rainfall durations over 2 years return period is located at 1/3 over the whole rainfall period. Although the rainfall intensity of rainfall peak presents a trend of decreasing-increasing-decreasing as the rainfall duration increases, the amplitude of variation is small. There are some common features of short duration storm patterns by P & C and Chicago methods, such as“ single-peak pattern, fast speed, high intensity, and long-lasting”. So, the departments of the water conservancy bureau, the hydrology bureau, the residential construction and the flood control need to prepare for drainage early on, when the short duration storm happens.

     

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