湿润地区暴雨特征对城市化响应研究

Research on the Response of Rainstorm Characteristics to Urbanization in Humid Areas

人类活动使得暴雨发生频率和强度增加,暴雨特征发生显著改变。厘清城市化对暴雨特征的影响对城市防洪减灾具有重要意义。以中国广东省广州市为例,利用处于不同行政区的11个雨量站点在2006—2019年期间收集到的逐15min降水数据,识别场次暴雨;从暴雨雨量、日数、雨强、次数、雨型、雨峰占比和雨峰系数7个方面,分析湿润地区暴雨特征对城市化的响应表现。结果表明:(1)城市化率较高区的暴雨雨量、日数、强度和次数均高于城市化率较低区,暴雨次数在时序变异性上则相反;(2)城市化对暴雨雨型无显著性影响,广州市各区雨型占比差异不大,且暴雨大多为单峰型,占比约63%;(3)暴雨雨峰占比对城市化响应不明显,其与降雨历时呈负相关关系,短历时暴雨特征由峰值雨量主导,而长历时和超长历时的暴雨事件中的持续时间是影响雨量的主要因素;(4)广州短历时和超长历时暴雨雨峰系数受城市化影响显著,城市化率较高区明显高于城市化率较低区;此外,广州暴雨雨型大多为前期集中型单峰暴雨,但城市化率较高区的超长历时暴雨大多偏后期集中型,需要特别注意。

Human activity increases the frequency and intensity of heavy rainfall and significantly changes the rainstorm character-istics.Clarifying the impact of urbanization on the characteristics of rainstorm is of great significance for urban flood control and disaster reduction.Based on the 15-minute precipitation data of 11 rainfall stations in different administrative regions from 2006 to 2019,this study took Guangzhou City,Guangdong Province,China as an example,analyzed the response of rainstorm character-istics to urbanization in humid areas from seven aspects:rainfall amount,intensity,frequency,number of days,type,ratio of peak and peak coefficient.The results indicate:(1)The amount,number of days,intensity and frequency of rainstorm in the area with higher urbanization rate are higher than those in the area with lower one,while the frequency of rainstorm is opposite in temporal variability.(2)The impact of urbanization on rainstorm patterns is not significant.The distribution of rainfall patterns across dis-tricts in Guangzhou are not notable,and most of them are single-peak patterns,around 63%of the total.(3)The rainstorm peaks does not show a significant response to urbanization,and it has a negative correlation with duration.Short-duration rainstorms are dominated by peak rainfall,while in long-duration and ultra-long-duration rainstorm events,of which the duration is the main fac-tor affecting rainfall changes.(4)The influence of urbanization on the peak coefficient of short-duration and ultra-long-duration rainstorms in Guangzhou is significant,with the areas of higher urbanization rates having noticeably higher coefficients than those of lower urbanization rates.Additionally,most of Guangzhou's rainstorm patterns are of the early-stage concentrated type with a single peak,but for areas with higher urbanization rates,the ultra-long-duration rainstorms are mostly of the late-stage concen-trated type,which requires special attention.