简介：与Zebiak藤条模型和parameterized一起强迫的intraseasonal的随机的表示，为ElNi的春天可预测性障碍(SPB)上的Madden-Jullian摆动(MJO)的无常的影响?o南部的摆动(ENSO)预言被学习。强迫的MJO的parameterized形式身体上被加到Zebiak藤条模型在与ElNi联系的SPB上获得所谓的Zebiak-Cane-MJO模型然后起始的错误，随机的模型错误，和他们的联合错误模式的效果?o预言被估计。当起始的错误能做时，结果证明强迫的随机的MJO引起的模型错误几乎不能导致重要SPB；而且，起始的错误的联合错误模式和与随机的MJO强迫联系的模型错误能也导致重要SPB。这些证明起始的错误可能是SPB的主要错误来源，它可以为ENSO预报提供数据吸收的一个理论基础。

简介：Temporalandspatialevolutioncharacteristicsofthe30-60dayoscillation(intraseasonaloscillation,ISO)ofsummerrainfallinChinaandtheeffectsofEastAsianmonsoonontherainfallISOareanalyzedinthispaper.Resultsshowthattheannualanddecadalvariationsoftheoscillationexistbetween1960and2008,andtheintensityisweakestinthelate1970sandearly1980s.InthetypicalstrongyearsoftherainfallISOobtainedfromempiricalorthogonalfunctions(EOFmode1),ananticycloneisinnorthwesternPacificandacycloneisintheeastofChina.Inthetypicalweakyears,thewindISOismuchweaker.Thelow-frequencyzonalwindandwatervaportransportfromthelowlatitudestomid-latitudesinthetypicalstrongyears,andtheoscillationstrengthofdiabaticheatingismuchstrongerthanthatintheweakyearsoftherainfallISO.TheanomalycharacteristicsoftherainfallISOshowanti-phasesbetweentheYangtzeRiverbasinandsouthofChina.AsforthetypicalstrongyearsoftherainfallISOintheYangtzeRiverbasin(EOFmode2),themainoscillationcenterofwatervaporisintheeastofChina(20-30°N,110-130°E).Inthepeak(break)phaseoftherainfalloscillation,alow-frequencycyclone(anticyclone)isintheYangtzeRiverbasinandananticyclone(cyclone)isnearTaiwanIsland.Inaddition,thepeakrainfallcorrespondstotheheatsourceintheYangtzeRiverbasinandtheheatsinkintheQinghai-TibetPlateau.AsforthetypicalstrongyearsoftherainfallISOinthesouthofChina,themainoscillationcenterofwatervaporissouthof20°N.Inthepeak(break)phaseoftherainfallISO,alow-frequencycyclone(anticyclone)isinthesouthofChinaandananticyclone(cyclone)isinthePhilippines.ThepeakrainfallcorrespondstotheheatsourceinthesouthofChinaandtheSouthChinaSea,andtheheatsinkinthewestofIndochina.

简介：TheElNino-SouthernOscillation(ENSO)ismodulatedbymanyfactors;mostpreviousstudieshaveemphasizedtherolesofwindstressandheatfluxinthetropicalPacific.Freshwaterflux(FWF)isanotherenvironmentalforcingtotheocean;itseffectandtherelatedoceansalinityvariabilityintheENSOregionhavebeenofincreasedinterestrecently.Currently,accuratequantificationsoftheFWFrolesintheclimateremainchallenging;therelatedobservationsandcoupledocean-atmospheremodelinginvolvelargeelementsofuncertainty.Inthisstudy,weutilizedsatellite-baseddatatorepresentFWF-inducedfeedbackinthetropicalPacificclimatesystem;wethenincorporatedthesedataintoahybridcoupledocean-atmospheremodel(HCM)toquantifyitseffectsonENSO.AnewmechanismwasrevealedbywhichinterannualFWFforcingmodulatesENSOinasignificantway.Asadirectforcing,FWFexertsasignificantinfluenceontheoceanthroughseasurfacesalinity(SSS)andbuoyancyflux(QB)inthewestern-centraltropicalPacific.TheSSSperturbationsdirectlyinducedbyENSO-relatedinterannualFWFvariabilityaffectthestabilityandmixingintheupperocean.Atthesametime,theENSO-inducedFWFhasacompensatingeffectonheatflux,actingtoreduceinterannualQBvariabilityduringENSOcycles.TheseFWF-inducedprocessesintheoceantendtomodulatetheverticalmixingandentrainmentintheupperocean,enhancingcoolingduringLaNinaandenhancingwarmingduringElNino,respectively.TheinterannualFWFforcing-inducedpositivefeedbackactstoenhanceENSOamplitudeandlengthenitstimescalesinthetropicalPacificcoupledclimatesystem.

简介：BasedontheNCEP/NCARreanalysisdataandtheobservedprecipitationdatainthesouthofChinafrom1958to2000,theimpactof30to60dayoscillationofatmosphericheatsourcesonthedroughtandfloodeventsinJuneinthesouthofChinaisdiscussed.Duringtheflood(drought)events,thereexistsananomalouslow-frequencyanticyclone(cyclone)atthelowlevelofthetroposphereovertheSouthChinaSeaandthenorthwesternPacific,accompaniedwithanomalouslow-frequencyheatsinks(heatsources),whilethereexistsananomalouslow-frequencycyclone(anticyclone)withanomalousheatsources(sinks)overtheareafromthesouthofChinatothesouthofJapan.Onaverage,thephaseevolutionofthelow-frequencyindroughteventsis7to11daysaheadofthatinfloodeventsinMaytoJuneinthesouthofChina.Infloodevents,low-frequencyheatsourcesandcyclonesarepropagatednorthwardfromthesouthernSouthChinaSea,northwestwardfromthewarmpoolofthewesternPacificandwestwardfromthenorthwesternPacificaround140°E,whichhaveveryimportantimpactontheabundantrainfallinJuneinthesouthofChina.However,indroughtevents,thenorthwardpropagationsofthelow-frequencyheatsourcesandcyclonesfromtheSouthChinaSeaanditsvicinityareratherlatecomparedwiththoseinfloodevents,andthereisnoobviouswestwardpropagationoftheheatsourcesfromthenorthwesternPacific.Thetimingofthelow-frequencyheatsourcepropagationhasremarkableimpactontheJunerainfallinthesouthofChina.

简介：Daily850-hPameridionalwindfieldsinEastAsiafromMarchtoSeptember2002wereusedtoestablishamodeloftheprincipaloscillationpattern(POP).Thismodelwasthenusedtoconductindependentextended-rangeforecastsoftheprincipaltemporalandspatialvariationsinthelow-frequencymeridionalwindfieldonatimescaleof20-30days.ThesevariationsaffecttheoccurrenceofheavyprecipitationeventsinthelowerreachesoftheYangtzeRivervalley(LYRV).Theresultsof135forecastexperimentsduringthesummerhalfyearshowthatthepredictedandobservedanomaliesarestronglycorrelatedataleadtimeof20days(meancorrelationgreaterthan0.50).Thisstrongcorrelationindicatesthatthemodeliscapableofaccuratelyforecastingthelow-frequencyvariationsinmeridionalwindthatcorrespondedtothe3heavyprecipitationeventsintheLYRVduringthesummerof2002.Furtherforecastexperimentsbasedondatafrommultipleyearswithsignificant20-30-dayoscillationsshowthatthesepredictionmodesareeffectivetoolsforforecastingthespace-timeevolutionofthelow-frequencycirculation.ThesefindingsofferpotentialforimprovingtheaccuracyofforecastsofheavyprecipitationovertheLYRVatleadtimesof3-4weeks.