辽宁葫芦岛市新旧暴雨强度公式对比及暴雨雨型分析

Comparison of new and old rainstorm intensity formulas and the designed rainstorm pattern for Huludao

根据1973—2014年葫芦岛市分钟降雨资料建立暴雨统计样本,通过对比分析确定采用年最大值法,基于P-Ⅲ型概率分布曲线拟合,推求出新一代暴雨强度公式。对比新、旧暴雨强度公式,5~30 min历时各重现期雨强以旧暴雨强度公式计算结果偏大,新、旧公式计算的45 min历时各重现期雨强基本相当,60~180 min历时各重现期雨强以新暴雨强度公式计算结果较大。在此基础上,开展葫芦岛市短历时暴雨雨型研究。统计确定雨峰位置系数为0.32,采用芝加哥雨型进行短历时暴雨雨型分析,重现期2 a、降雨历时60、90、120、150、180 min的累计降雨量在38.73~66.99 mm,均以初期累计降雨增长较慢,雨峰前后增长速度较快,之后降雨增速明显放缓。

Based on the minute precipitation data from 1973 to 2014 at Huludao, we establish rainstorm statistical samples. The revision of rainstorm intensity formula at Huludao was carried out by the annual maximum value method. The probability curves were followed by P-Ⅲdistribution, and the formula parameters were calculated. The rain intensity calculated by the old formula from 5 to 30 minutes of each return period are lager than that calculated by the new method. The rain intensity calculated by the new and old formula of 45 minutes of each return period are basically equivalent. The rain intensity calculated by the new formula from 60 to 180 minutes of each return period are lager than that by the old method. Based on these results, the designed rainstorm pattern at Huludao is studied. Using the coefficient of rain peak position of 0.32, and the designed rainstorm pattern of the Chicago, the accumulated precipitation of rainstorm pattern of return period of 2 a lasted 60, 90, 120, 150, 180 minutes are between 38.73 to 66.99 mm. It increases slowly early in the precipitation, but increases faster around the rain peak, then increases slowly again.