揭阳市气象干旱变化特征及成因分析  

Analysis of the Variation Characteristics of Meteorological Drought in Jieyang and Its Causation

作　　者：王周玉 刘泳涛 王永康 黄河莎 WANG Zhou-yu;LIU Yong-tao;WANG Yong-kang;HUANG He-sha(Meteorological Bureau of Puning,Puning 515300;Meteorological Bureau of Huilai,Huilai 515200;Meteorological Bureau of Jieyang,Jieyang 515300)

机构地区：[1]普宁市气象局,广东普宁515300 [2]惠来县气象局,广东惠来515200 [3]揭阳市气象局,广东揭阳515300

出　　处：《广东气象》2023年第2期14-17,共4页Guangdong Meteorology

基　　金：揭阳市气象局科技计划项目(202105、202217)。

摘　　要：为揭阳市今后气象干旱预测和防灾减灾提供理论依据,基于1967—2021年揭阳市逐日降水量和逐日气象干旱指数DI,以及NCEP/NCAR和NOAA月尺度再分析资料,采用线性趋势分析、小波分析等方法,分析了揭阳市气象干旱变化特征及其成因。结果表明:近55年来揭阳干旱总体略有加强但并不显著,干旱日数的主周期为准3年振荡;揭阳干旱主要集中在非汛期(即11月至翌年3月),约占全年干旱日数的75%;高层副热带西南急流主体偏北偏弱,冷空气影响较弱,同时低层南支槽偏弱,广东和南海地区异常下沉,阻挡了孟加拉湾和南海的水汽向揭阳输送,缺乏冷暖空气汇合导致揭阳干旱的发生。To offer theoretical evidence for future drought prediction and disaster prevention and mitiga⁃tion in Jieyang,this work analyzes the variation characteristics of the city's meteorological drought and its causation based on the daily rainfall amount and the daily drought index of DI as well as the monthly reanaly⁃sis from NCEP/NCAR and NOAA for the years from 1967 to 2021 and with the methods of linear tendency a⁃nalysis and wavelet analysis.The results are shown as follows.For the 55 years studied,the drought of Jiey⁃ang intensified generally but insignificantly,with the primary oscillation period of drought days at quasi⁃3 years.The drought mainly occurred in non⁃rainy seasons,i.e.,from November to the following March,tak⁃ing up about 75%of the annual total duration.The bulk of an upper⁃level subtropical southwesterly jet stream was more northward and weaker and cold air was weaker than the climatology,while a low⁃level southern branch of the westerlies was weaker than the climate mean and the air was anomalously descending over the province of Guangdong and the South China Sea region.As a result,it blocked the transport of wa⁃ter vapor to Jieyang from the Bay of Bengal and the South China Sea,leading to the generation of the drought due to the lack of cold air converging with warm air.

关 键 词：气候学 气象干旱 干旱指数 揭阳 

分 类 号：P46[天文地球—大气科学及气象学]