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X(,,100029)(),,;,,,,2002,,(),,,,,:,,,12090,,,[1,2]2002,,,,2002683,,,1998,,5,30N,,,;,,[3,4][5]:,,,,50a,,,62320046ACTAMETEOROLOGICASINICAVol.62,No.3June2004X:2003917;:2004211:(ZKCX22SW2210)#40135020,,(22.530N,115140E),();,[5]NCEP/NCAR195016022.11951200050a160(1),,0.5,,(),;(),,,1(0.05,,)Fig.1ThecorrelationbetweentheindexoflongitudinalpositionofsubtropicalhighinthewesternPacificinsummerandthesurfacetemperature(Theshadedareasindicatethesignificantreaches0.05.Solidlinesshowthepositivecorrelationsanddashedlines,negativecorrelations)2.2,500hPa(2),,,,,,,,,,,500hPa(3,9033:[5])1,,,3,,,:50N,,,,,[6],;2,,2500hPa(0.05,,)Fig.2Thecorrelationbetweentheindexoflongi2tudinalpositionofsubtropicalhighintheWesternPacificinsummerand500hPaheightovertheNorthernHemisphere(Theshadedareasindicatethesignificantreaches0.05.Solidlinesshowthepositivecorrelationsanddashedlines,negativecorrelations)(3),,;(),3(5,0)Fig.3Thecompositechartofanomalyheightat500hPawhenthesubtropicalhighoverthewesternPacificlocatesrathertotheeast(Theareasofabsoluteanomalyvaluesmorethan5gpmareshaded.Thelightshadosrepresentpositivevalues.Thedarkones,negative),,,,,,,,32002200201362683,618,71115730837,3338,4043,71441.1,19157[7]3.1200242002500hPa2588dagpm,3,588120E,3,120E584dagpm588dagpm140E,-60gpm,74200222.527.5N500hPa2(:,:;:,:588dagpm)Fig.4Time-longitudinalcrosssectionof500hPaheightanditsanomalies.alongthelatitudesof22.5-27.5Ninsummerof2002(Solidlines:thecontoursof500hPaheight.Heavysolidlines:588dagpm,Shadedareas:positiveanomalyvalues.Dashedlines:negativeanomalyvalues.Unit:dagpm).1133:3.220027,20027,-,,588dagpm140E-60gpm,13.2.15ab751071115500hPa,,,4,110E,:,588dagpm140160E,,,586dagpm[1]1999,,,,1(5a),,,,,,,,[8],,,5500hPa(a.20027610,b.200271115;:3;:-3;:;:,:586dagpm:dagpm)Fig.5500hPaheightanditsanomaly.(a)Averagein6-10,July,2002.(b)averagedin1115,July,2002.Solidlines;contoursof500hPa,darksolidlines:contourof588dagpm.Darkshadedarea:positiveanomaly.lightshadedarea:negativeanomaly.Dashedline:thezerolineofheightanomaly.Unit:dagpm3.2.2,671115850hPa6a,,,,130E,,21362(6b),130E,,6200271115850hPa(a)(b)(:kg/(ms))Fig.6Thevectorofmoistureflux(a)anditsanomaly(b)at850hPaaveragedin1115,July,2002(Unit:kg/(ms))7200271115850hPa(:kg/dm2hPa108)Fig.7Theanomalydivergenceofmoisturefluxat850hPaaveragedin1115,July,2002(Unit:kg/dm2hPa108)7200271115850hPa,(6b):,,,,,,(),,;,,,,3.2.33133:820027111528a,b(37.542.5N)(27.532.5N),8a,90140E,110E,5d,140E,8b,140E5:,,82002711152(a.37.542.5N,b.27.532.5N)Fig.8Thepressure-longitudecrosssectionofanomalyflowaveragedin1115,July,2002.(a.37.542.5N,b.27.532.5N)4(1),(),;(),(2),500hPa,,,,41362,,,(3)2002,,,(4),,,,,(),,;,,,,(5),1999,,1,,.I:.,1999,4(4):3233332,,.II:.,1999,4(4):3343453.98.:,1998.139pp4,,.19987.,1998,3(4):3683815YangHui,SunShuqing.StudyonthecharacteristicsoflongitudinalmovementofsubtropicalhighinthewesternPacificinsummeranditsinflu2ence.AdvancesinAtmosphericSciences,2003,20(6):9219336HuangRonghui.TheEastAsia/PacificpatternteleconnectionofsummercirculationandclimateanomalyinEastAsia.ActaMeteorologicaSinica,1992,6(1):25367.,-20027.,2002,28(10):58618,..:..:,1997.1691885133:RELATIONSHIPBETWEENTHEANOMALYLONGITUDINALPOSITIONOFSUBTROPICALHIGHINTHEWESTERNPACIFICANDSEVEREHOTWEATHERINNORTHCHINAINSUMMERWeiJieYangHuiSunShuqing(InstituteofAtmosphericPhysics,AcademiaSinica,Beijing100029)AbstractThereexistsagoodrelationshipbetweenthelongitudinalpositionofthesubtropicalhighinthewesternPa2cificandthetemperatureinthenorthChinainsummertime.Aremarkablepositivecorrelationregionwithaval2uemorethan0.6atthecenterindicatesthatwhenthesubtropicalhighmoveseastward,thetemperatureinnorthChinawouldincreaseandviseversa.Theanomalouslongitudinalpositionofthesubtropicalhighiscloselyassociatedwiththevariationofthelongwavepatterninthewesterlies,henceinfluencesthetemperatureofnorthChina.Moreover,theperturbationresultingfromthechangeofthelongitudinalpositionofthesubtropicalhighwouldpropagate,asawavetrain,northwardtothepolarregionthentheNorthAmericathusinfluencethewesterliesinamuchwiderrange.Alongspellofhotanddryweatherintheyearof2002summerinnorthChinaisanalyzed.Thepositionofthesubtropicalhighinthatsummerconsistentlylocatestotheeast.ThecontinentalsubtropicalhighinthewestextendseastwardtomergewiththeridgeinthewesterliesandcoveringnorthChinaarea,bringingaboutahightemperaturethere.Thelongitudinalpositionofthesubtropicalhighfixestothenorthwardturningpointandthetrackofthemonsooncurrent,whichwouldalsobethepathofthewatervaportransfer.Aeastwarddisplace2mentofthesubtropicalhighwouldleadtotheeastwardshiftofthewatervaporchannel,awayfromtheeasternAsiancontinent.Therefore,thesupplyofwatervaporwouldbecomeverypoorthere,especiallyinnorthChina,resultinginaverydryweather.Thehightemperatureinthiscaseisdirectlycausedbytheintensedescendingcurrentinthecontinentalsubtropicalhigh.Keywords:Anomalouslongitudinalpositionofsubtropicalhigh,Sustainedhightemperatureinsummer,Supplyofwatervapour,Descendingcurrent.61362