广东省降雨时空分布特征分析

Analysis of spatiotemporal distribution characteristics of rainfall in Guangdong Province

全球气候变暖背景下,极端天气频发,分析区域降雨时空分布特征及变化趋势是防灾减灾的前提。基于广东省2017—2021年4119个雨量站实测数据,运用反距离权重、GIS等方法分析了广东省降雨时空变化特征及形成机理。结果表明:(1)2017—2021年降雨量范围为1420.9~1993.6 mm,呈间断上升趋势,2019年为近5年最高,2020年和2021年是罕见的连旱年。(2)年内分布不均,暴雨集中在夏季,占全年降雨量的49.06%,其次是春季、秋季和冬季;4—6月前汛期多为锋面雨,7—9月后汛期多为台风雨和对流雨,10月至次年3月为少雨季节。(3)空间上降雨分布特点为:粤西和粤中珠三角北缘地区降雨多,粤东及粤东北山区降雨少。(4)1 h短时强降雨天气多发生在夏季并活跃于17—19时段;空间上,南部沿海平原地区最频繁,北部山区次之但存在强降雨诱发地质灾害等风险;1 h超100 mm降雨主要集中在清远—佛冈一带。研究结果为广东省强降雨诱发的洪涝灾害防御提供参考借鉴。

In the context of global climate warming and frequent extreme weather events,analyzing the spatiotemporal distribution characteristics and trends of regional rainfall is crucial for disaster prevention and mitigation.Based on the observed data of 4119 rainfall stations in Guangdong Province from 2017 to 2021,this study utilized inverse distance weighting and GIS to analyze the spatiotemporal changes and formation mechanisms of rainfall in Guangdong Province.The results are as follows:①The annual precipitation ranged from 1420.9 to 1993.6 mm,showing an intermittent upward trend.2019 had the highest rainfall in the last five years,while 2020 and 2021 were rare consecutive drought years.②The distribution of rainfall throughout the year was uneven,with heavy rainfall concentrated in the summer,accounting for 49.06%of the annual precipitation,followed by spring,autumn,and winter.The pre-monsoon period from April to June was dominated by frontal rain,while the postmonsoon period from July to September was characterized by tropical cyclone rain and convective rain.The period from October to March of the following year was the dry season.③Spatially,the distribution of rainfall showed that the western and central parts of Guangdong Province,as well as the northern edge of the Pearl River Delta,had higher rainfall,while the eastern and northeastern mountainous areas had less rainfall.④Short-duration heavy rainfall of 1 hour mainly occurred in summer and was most active between 17:00 and 19:00.In terms of spatial distribution,it was most frequent in the southern coastal plain area,followed by the northern mountainous region which also posed risks of geological disasters induced by heavy rainfall.Observations of rainfall exceeding 100 mm in 1 hour were mainly concentrated in the Qingyuan-Fogang area.These findings provide valuable references for disaster defense against heavy rainfall-induced hazards in Guangdong Province.