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简介:SincethelastInternationalUnionofGeodesyandGeophysicsGeneralAssembly(2003),predictabilitystudiesinChinahavemadesignificantprogress.Fordynamicforecasts,twonovelapproachesofconditionalnonlinearoptimalperturbationandnonlinearlocalLyapunovexponentswereproposedtocopewiththepredictabilityproblemsofweatherandclimate,whicharesuperiortothecorrespondinglineartheory.Apossiblemechanismforthe'springpredictabilitybarrier'phenomenonfortheElNi(?)o-SouthernOscillation(ENSO)wasprovidedbasedonatheoreticalmodel.ToimprovetheforecastskillofanintermediatecoupledENSOmodel,anewinitializationschemewasdeveloped,anditsapplicabilitywasillustratedbyhindcastexperiments.Usingthereconstructionphasespacetheoryandthespatio-temporalseriespredictivemethod,Chinesescientistsalsoproposedanewapproachtoimprovedynamicalextendedrange(monthly)predictionandsuccessfullyappliedittothemonthly-scalepredictabilityofshort-termclimatevariations.Instatisticalforecasts,itwasfoundthattheeffectsofseasurfacetemperatureonprecipitationinChinahaveobviousspatialandtemporaldistributionfeatures,andthatsummerprecipitationpatternsovereastChinaarecloselyrelatedtothenorthernatmosphericcirculation.Forensembleforecasts,anewinitialperturbationmethodwasusedtoforecastheavyraininGuangdongandFujianProvinceson8June1998.Additionally,theensembleforecastapproachwasalsousedforthepredictionofatropicaltyphoons.Anewdownscalingmodelconsistingofdynamicalandstatisticalmethodswasprovidedtoimprovethepredictionofthemonthlymeanprecipitation.Thisnewdownsealingmodelshowedarelativelyhigherscorethantheissuedoperationalforecast.
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