简介：TheLS-SVM(Leastsquaressupportvectormachine)methodispresentedtosetupamodeltoforecasttheoccurrenceofthunderstormsintheNanjingareabycombiningNCEPFNLOperationalGlobalAnalysisdataon1.0°×1.0°gridsandcloud-to-groundlightningdataobservedwithalightninglocationsysteminJiangsuprovinceduring2007-2008.Adatasetwith642samples,including195thunderstormsamplesand447non-thunderstormsamples,arerandomlydividedintotwogroups,one(having386samples)formodelingandtherestforindependentverification.ThepredictorsareatmosphericinstabilityparameterswhichcanbeobtainedfromtheNCEPdataandthepredictandistheoccurrenceofthunderstormsobservedbythelightninglocationsystem.Preliminaryapplicationstotheindependentsamplesfora6-hourforecastofthunderstormeventsshowthatthepredictioncorrectionrateofthismodelis78.26%,falsealarmrateis21.74%,andforecastingtechnicalscoreis0.61,allbetterthanthosefromeitherlinearregressionorartificialneuralnetwork.

简介：Thestudypresentedhereininvestigatedthemaincharacteristicsofcarbonmonoxideintraseasonalvariabilityandevaluateditspossibleimpactfactorsusingtheuppertroposphereandlowerstratosphere(UT/LS)AuraMicrowaveLimbSounder(MLS)observationsoverTibetanPlateauanditsadjacentareasinsummer(JunetoAugust)of2005and2006.ObservationsshowapersistentconstituentextremeextendingupintotheUT/LSthroughoutsummer,aswellasatemporallyreversedphasevariationbetweenthecarbonmonoxideandozoneinUT/LS.Theintraseasonaloscillations(ISOs)ofcarbonmonoxideduringsummerareinvestigatedbyusingmethodsofwaveletandbandpassfilteranalysis.ItisfoundthatISOsovertheTibetanPlateauhaveperiodsof10to20daysand30to60days.Theformermainlyappearedinuppertropospherewhilethelatterinlowerstratosphere.FurtheranalysisshowsthatthesetwoperiodsofISOsinUT/LSaremainlyinphasetotheactivitiesofconvectionoverthesouthoftheplateauandthevariationofSouthAsiaHigh,respectively.TheabovetwofactorsandtheirdynamicalcouplingmayberesponsibleforthetracerISOsatdifferentlevels.