On the Climatological Variation Characteristics of Areal Rainfall in the Basin of Dongjiang River
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.
climatologyareal rainfallclimate changeabrupt changeDongjiang River basin
万方数据
维普
