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1、第30卷第2期大气科学Vol130No122006年3月ChineseJournalofAtmosphericSciencesMar.2006中国北方干旱化年代际特征与大气环流的关系1,2,321李新周马柱国刘晓东1中国科学院地球环境研究所,西安7100752中国科学院大气物理研究所东亚区域气候环境重点实验室,北京1000293中国科学院研究生院,北京100049摘要用CRU和ECMWF资料分析了近代中国北方干湿变化特征及其与东亚大气环流异常特征的关系。结果表明:中国北方干旱化具有显著的年际、年代际特征,20世纪70年代末
2、干湿发生显著转变,西北东部和华北地区变干趋势明显,北方大部分地区干旱现象严重;中国北方地区当前的干旱化时空格局与东亚夏季风异常特征密切相关,夏季风减弱以及由此造成水汽输送量减少是导致干旱化发展的主要原因,而低层大气反气旋环流增强和气旋性环流减弱是引起干旱化的异常环流特征。关键词干旱化水汽输送东亚夏季风中国北方地区文章编号10069895(2006)02027708中图分类号P461文献标识码AInter-decadalCharacteristicsofAridificationoverNorthernChinaAssoci
3、atedwiththeVariationofAtmosphericCirculationDuringthePast50Years1,2,321LIXin-Zhou,MAZhu-Guo,andLIUXiao-Dong1InstituteofEarthEnvironment,ChineseAcademyofSciences,Xi.an7100752KeyLaboratoryofRegionalClimateEnvironmentResearchforTemperateEastAsia,InstituteofAtmospheri
4、cPhysics,ChineseAcademyofSciences,Beijing1000293GraduateUniversityofChineseAcademyofSciences,Beijing100049AbstractAridificationovernorthernChinaiscurrentlyoneofthemosturgentlivingenvironmentalissuesinourcountry.Alotofstudieshavebeencarriedoutconcerningitsevolution
5、,causesandprediction,etc.Therearediffer-entgeneralcirculationpatternsateachdry/wetstagesundoubtedly.Inotherwords,anabruptadjustmentofsum-mermonsooncirculationoverEastAsiawillresultinadistinctchangeoftheprecipitationpattern.However,uptonow,analysesontherelationship
6、betweennorthernChinadroughtandthesummersouthwindhavebeenverylimit-ed.Inthispaper,inter-decadalcharacteristicsofaridificationovernorthernChinaanditsassociationwiththevaria-tionofatmosphericcirculationduringthepasthalfcenturyareanalyzedbasedonthelatestECMWFandCRUrea
7、na-lyzedmonthlygriddata.TobetterdescribethedetailedtemporalandspatialfeaturesofdroughtsinnorthernChina,thenorthernChinaisdividedinto4sub-regionsandtheannualPalmerDroughtSeverityIndex(PDSI)iscalculatedineveryunitrespec-tively.ItisshownthattheannualprecipitationandP
8、DSIhavedecreasedsignificantlyinsub-regionsBandCoverthepast50years.Whileinsub-regionA,theannualprecipitationandPDSIhaveanincreasingtrendfromtheendof1950s
