粤北山区2013—2022年短时强降水的统计特征

Statistical Characteristics of Short-term Intense Rainfall from 2013 to 2022 in the Mountainous Areas of Northern Guangdong

针对地形复杂的粤北山区,基于2013—2022年412个地面气象观测站逐小时降水数据,总结粤北山区短时强降水时空分布特征。结果表明:(1)粤北山区短时强降水频次有明显的年际变化,平均强度没有明显年际差异。(2)粤北山区短时强降水5月最多,6月次之,8月更次之;南海季风爆发时间和强度对粤北山区短时强降水频次及雨强甚至极端雨强都没有明显指示意义。(3)粤北山区短时强降水日变化呈双峰型,17:00前后为主高峰、06:00前后为次高峰;从冬到秋季,主高峰由凌晨过渡到傍晚。(4)短时强降水的空间分布大体呈现西南多东北少,易发区主要集中在清远英德到河源龙门一带。4到6月以佛冈为中心显著增多;7到9月短时强降水多发生于山谷地区。

For northern Guangdong,the mountainous part of the province with complicated terrain,this study summarized the spatiotemporal distributions of shortterm intense rainfall(to be referred to as“SI rainfall”hereafter)based on the hourly rainfall data from 412 surface meteorological observation stations from 2013 to 2022.The results are shown as follows.(1)The SI rainfall shows significant interannual variations in occurrence frequency but it is not so in average intensity.(2)The SI rainfall is the most in May,followed in turn by June and August.The outburst date and intensity of the South China Sea summer monsoon are not clear indicators for the occurrence frequency,rain rate or even the extreme rain rate of the SI rainfall.(3)The SI rainfall is bimodal in diurnal variation,with the primary peak around 17:00 and the secondary peak around 06:00.On the temporal scale,the primary peak shifts from early morning before dawn in winter to early evening at nightfall in autumn.(4)Spatially speaking,the SI rainfall is generally observed more in the southwest than in the northeast,with the most preferred area in Yingde,Qingyuan through Longmen,Heyuan.The SI rainfall increases significantly in the areas centered around Fogang from April to June and it is most likely to take place in mountain valleys from July to September.