21世纪以来广州强降水的若干变化特征

On a Number of Variation Characteristics of Intense Rain in Guangzhou Since the 21st Century

基于广州国家和区域自动观测站的分钟、小时降水观测数据,分析了21世纪以来广州强降水事件的变化特征。结果表明:21世纪以来广州年降水量、大雨日数、暴雨日数均呈明显增加趋势,即强降水发生概率增加。同时短历时强降水极值和频次比长历时降水增强、增多趋势更加显著。空间上,全市有5个短时强降水中心,其中4个与地形强迫作用有关,1个则与城市"雨岛"效应有关。时间上,短时强降水事件集中出现在汛期,且在汛期的降水集中期增多,降水间歇期减少,午后至傍晚是短时强降水的高发期。局地性、突发性和增长性是广州短时强降水事件的主要特征。

Using the minute-and hour-based data of precipitation from the national and regional automatic observation stations in Guangzhou,this paper analyzes the variation characteristics of intense rain events since the 21 st century.The result is shown as follows.Since the 21 st century,the annual rain amount and the number of days with intense rain have shown significantly increasing trends,i.e.,the probability has increased for intense rain to take place.Concurrently,short-range intense(SRI)rain increases in extreme values and longer-range rain increases in both intensity and frequency.Spatially speaking,there are five short-range intense rain centers in the city,four of which are related with the forcing of terrain and the remaining one with the effect of"rain island".Temporally speaking,the SRI rain concentrates in the raining season,with more periods of rain concentration and less periods of rain break.After midday the SRI rain happens the most till early evening.For the city of Guangzhou,the SRI rain is characterized by locality,abruptness and growth.