郑州“7·20”特大暴雨降水特征及其内涝影响

Precipitation characteristic and urban flooding influence of“7·20”extreme rainstorm in Zhengzhou

基于郑州市自动气象观测站资料,对河南郑州2021年“7·20”特大暴雨的降水极端性、降水时段、小时降水变化等特征及其内涝影响进行分析,提出超标准降水条件下内涝防治的建议。分析表明:河南郑州“7·20”特大暴雨是一次极端强降水天气过程,可以分为5个明显的降水阶段,第三阶段和第四阶段呈现短时强降水频发、重发特征,特别是20日12—18时郑州市主城区连续出现80 mm以上的小时降水,是造成郑州市主城区严重城市内涝的主要原因。按照现有的内涝防治设计标准,郑州市主城区仍不足以防范此种强度的降水,但仍可以通过完善城市内涝防治的超标应急系统、提高城市易涝点内涝防治标准等措施减轻内涝灾害。

Based on observations from automatic weather stations,the extremes,periods and hourly variation characteristics of precipitation and the urban flooding influence are analyzed for the“7·20”extreme rainstorm in Zhengzhou City,Henan Province,and some suggestions on the prevention and control of waterlogging under over standard precipitation conditions are put forward.The results show that this is an extreme precipitation weather process,and can be divided into five obvious precipitation periods.The short-term heavy precipitation shows characteristics of frequent occurrence and repeated occurrence at the third and fourth periods,while the continuous precipitation heavier than 80 mm/h in the main urban of Zhengzhou from 12:00 to 18:00 CST on 20 July is the principal cause of the serious urban flooding.The current design standards of unban flooding prevention is not enough to prevent precipitation with this intensity in the main urban area of Zhengzhou City,but we could reduce the flooding disasters by improving the emergency system of urban flooding prevention while exceeding standard,raising the urban flooding prevention standards at prone points,and measures like this.