西宁市短历时暴雨雨型及适用性分析

利用西宁市1954-2017年降水分钟数据建立暴雨统计样本，采用年最大值法推算暴雨强度公式并推求西宁市短历时暴雨雨型。结果表明：西宁市短历时暴雨雨型单峰特征比较明显，单峰峰值出现在前1/3。历时120 min芝加哥设计雨型综合雨峰位置系数0.27，雨峰位置在35 min左右，峰值前（后）雨强迅速增加（减小），最大1 h降水量为13.14 mm，降水主要集中在20～80 min。各历时的瞬时雨强变化趋势以及分布型基本一致，雨强随着重现期的增大而增大。累计降雨雨峰前（后）增长斜率升（降）最大。西宁市暴雨分布呈现局地性强，空间差异明显特征，芝加哥设计雨型结果对城西和城北区代表性较好，城中和城东区可参考使用。

Analysis of short duration rainstorm type and its applicability in Xining City

Using the minute-by-minute precipitation data from 1954 to 2017 in Xining City,a statistical sample of heavy rain was built. Based on this,the annual maximum method was used to calculate the storm intensity and the short duration rainstorm hyetograph in Xining. It is found that the characteristics of single rain peak of rainstorm with short duration were obvious with the single peak in the middle and anterior segments. The integrated rain peak position factor for the Chicago design rainstorm pattern was 0.27;the rain peak duration of 120 min was about 35 min. The rain intensity increased rapidly before the peak and decreased rapidly after the rain peak. The maximum hour precipitation was 13.14 mm,mainly concentrating in between 20 and 80 min. The instantaneous rain intensity change and distribution pattern of various duration were basically consistent,and the rain intensity increased with the increase of the return period. The slope of the cumulative rainfall peak before the rain peak was the largest,and the slope after the rain peak was the fastest. Before(after)the peak accumulated rainfall,the growth slope rose(fell)the most. The distribution of heavy rain in Xining was characterized by strong locality with obvious spatial difference. The results of the Chicago design rainstorm pattern are representative of the west and north districts of the city. The central and the east districts of the city can be used as a reference only.