广州市城市内涝特征分析

An Analysis of the Characteristics of Urban Floods in Guangzhou

基于水务部门排水管理中心的内涝灾情信息,运用统计学等研究方法,分析广州市城市内涝分布特征,结果表明:广州全市内涝点最多的是中心城区天河,最少的是郊区的从化。全年发生内涝次数最多的月份是5、6月,最少的月份是2、12月;全天最容易发生内涝的时间是08:00、13:00和19:00。内涝发生时对应的最大小时雨量主要集中在50~80mm,占55%;过程累计雨量在120mm以上占41.76%。内涝过程的最大小时雨量和累计雨量空间分布和内涝点的空间分布特征大致吻合,内涝过程平均小时雨量集中在30~50mm,占61%。从与致涝相关的天气系统来看,主要是东路或者西路冷空气配合中层的线槽及低层切变线的过程;另外副高边缘的摆动加上低层偏南风加大和台风过程也容易致涝。

Based on the information of urban floods released by the drainage management center of Guangzhou Municipal Water Bureau,this paper performs a statistical analysis of the distribution characteristics of urban floods in Guangzhou.The result is shown as follows.Annually,urban floods occur spatially the most in the central district of Tianhe and the least in the suburban district of Conghua,and temporally the most in May and June and the least in February and December.Diurnally,it is mostly likely for them to take place at 08:00,13:00 and 19:00,respectively.Maximum hourly rainfall with urban floods is mainly between 50 and 80 mm,taking up 55% of the total and 41.76% of accumulated life-cycle rainfall is more than 120 mm.The distribution of maximum hourly rainfall and accumulated rainfall generally agree with that of flooding locations,with life-cycle averaged hourly rainfall mostly between 30 and 50 mm,taking up 61% of the total.Flood-causing weather systems are mainly cold air from eastern or western routes with mid-level troughs and low-level shears.Besides,urban floods can also happen when the edge of a subtropical high swings together with strengthened low-level southerly and typhoon visits.