东江流域面雨量的气候变化特征

On the Climatological Variation Characteristics of Areal Rainfall in the Basin of Dongjiang River

基于东江流域12个国家气象站1967-2021年逐日降水量资料,采用泰森多边形、线性趋势、突变检验、周期分析等方法分析流域面雨量的气候变化特征。结果表明:东江流域年面雨量呈不显著的减少趋势,其旱年和涝年分别集中在多个年代际的初期和中期;丰、枯水期存在2~5和5~7年显著周期振荡。前汛期年平均面雨量较后汛期偏多,雨日较后汛期偏少。5-6、10-11月面雨量变化趋势差异大,出现旱涝急转的可能性较大。流域面雨量于1991年开始突变为阶段性不显著增加或减少的交替变化趋势,中雨、大雨量级面雨量分别在2002、1983年发生显著突变,暴雨量级面雨量无显著突变特征,但21世纪以来年暴雨面雨量异常偏多或偏少年份剧增,极端性特征突显。

Based on the daily rainfall data from 12 national meteorological observation stations in the basin of Dongjiang River from 1967 to 2021 and with the methods of Thiessen poligon,linear tendency,ab-ruptness test and periodic analysis,this work analyzed the climatological variation characteristics of areal rainfall.The results are shown as follows.The annual areal rainfall of Dongjiang R.basin shows an insignifi-cantly decreasing trend,with drought years and flood years concentrated in the early and middle stages of multiple interdecadal periods respectively.Significant periodic oscillations of two to five years(five to seven years)exist in high(low)flow seasons.For annual averages,the areal rainfall(number of rain days)is more(less)in the April-June rainy season than in the July-September rainy season.Monthly variations of the areal rainfall differ much from May to June and from October to November,with large probabilities of droughts(floods)abruptly changing to floods(droughts).Beginning from 1991,basin-wide areal rainfalls began to show alternative periodic trends of either insignificantly increasing or decreasing,with the intensity levels of moderate rain and heavy rain having significant abrupt changes in 2002 and 1983 respectively,while that of very heavy rain showed no such characteristics.It is noteworthy that the years with anomalously more or less annual areal rainfall on the level of very heavy rain have increased abruptly since the 2000s,showing significant characteristics of extremeness.