Warm-rain-process-convection暖雨過程對流課件

HeavyrainfallandflashfloodHeavyrainfallandflashflood1Warm-rain-process-convection暖雨過程對流課件2FlashFloodsFlashfloodsarethenumberoneweather-relatedkillerinovermuchoftheglobeNearlyhalfofallflashfloodfatalitiesareautorelatedFlashFloodsFlashfloodsaret3Warm-rain-process-convection暖雨過程對流課件4FlashFloodDefinitionIntensePrecipitationSmallfast-responsebasins“Asituationwherethecausativeprecipitationandthesubsequentrunoffareoccurringonthesamescales.”

NATOAdvancedStudyInstitute(1999)FlashFloodDefinitionIntense5FlashfloodforecastingTheflashflood-aprototypicalhydro-meteorologicaltopicAmeteorologicalevent:rainfallAhydrologicalsettingBasinresponsetimesRunoffcharacteristicsWorkingwithhydrologists?Flashflood“guidance”isanestimateoftherainfallneededforflashfloodingtooccurFlashfloodforecastingThefla6FloodconsiderationsLargeriversliketheYangtzerespondtotherainfalloveraperiodofdaysFlashfloods-responsetorainfallisveryrapid:periodofperhaps10sofminutesSmallbasinsincomplexterrainarethosemostlikelytohaveflashfloodsUrbanfloodingcanhaveimportantimpacts-highrunoff.FloodconsiderationsLargerive720070718JinanFlashFloodingEventJinanisthecapitalcityofShandongprovince.During12hperiodfrom14:00BST(BeijingStandardTime)18Julyto02:00BST19July2007,theaveragerainfallfrom123weatherstationsforwholeShandongprovinceis62mm.Itscapitalcity,Jinan,hasexperiencedmostsevererainfall.The12hrainfallindowntownareais140mm,mostoftherainfallwasprecipitatedduring3hperiodfrom17:20to20:20BSTon18July2007.25peoplewerekilledbytheflashfloodinginJinancity.20070718JinanFlashFlooding8AFFForecastingstrategyObtainflashfloodguidancefromhydrologists:theminimumrainfallperunittimeneededfortheoccurrenceofaflashfloodBeginwiththequestion:“Whatistheprobabilityofrainfallapproachingthatvaluetoday?”AFFForecastingstrategyObtai9Precipitationin

FlashFloodsAccumulation5-50cmover1-12hoursDurationMostlylessthan3hoursIntensity

Arid/semi-aridclimates7.5-20cm/hour(avg.11.5cm/hour)Humidclimates12.5-30cm/hour(avg.19cm/hour)CourtesyMattKelschPrecipitationin

FlashFloods10Precipitationin

FlashFloodsEnhancedIntensityPrecipitationefficiencyTropical,maritimeconnectionDeep,above-freezinglayerLow-leveljet,rapidmoisturereplenishmentLow-levelfocus(terrainandboundary)/class/FLOAT_2001/index.htmPrecipitationin

FlashFloods11ThelowleverjetThelowleverjet12ThelowleveljetThelowleveljet13ThelowleveljetfromsouthwestThelowleveljetfromsouthwe14LowleveljetfromeastandmiddleleveljetfromsouthwestLowleveljetfromeastandmi15BasinCharacteristics

inFlashFloodsSmall9-150km2(avg.55km2)70%mountainouswatersheds>50%alteredUrbanizationDeforestation,firescarsThin/impermeablesurfacelayer,Clay,rocks(lowinfiltration)Pavement(noinfiltration)Or,thick,saturatedsoillayersCourtesyMattKelschBasinCharacteristics

inFlash16FlashFloodForecastingInsomecasesthehydrologyisthedrivingforce,andsignificantflashfloodscanhappenwithunimpressiverainfall.“FlashFloodforecastingrequiresmorethanaccurateforecastsofexcessiveaccumulation.”

-MattKelsch(2000)FlashFloodForecastingInsome17FlashFloodForecastingKnowrunoffcharacteristicsSmall,fast-responsebasinsUrbanbasinsDeforestationandfirescarareas.HailremainingonedayafterCheyenne,WYflashfloodof

1August1984FlashFloodForecastingKnowru18FlashFloodForecastingKnowledgeofrelationshipofstormspeedanddirectiontostreamflowcanbecriticalFlashFloodForecastingKnowled19FlashfloodforecastingWhathappenstothewateronthegroundisjustasimportant,andinsomecasesmoreimportant.Knowyourbasins!Flashfloodforecasting20RainfallAmountBasically,theamountofrainfallthatfallsoveranareadependson:TheINTENSITYoftherainfallTheSIZEoftherainfallareaThePROPAGATIONoftherainfallareaRainfallAmountBasically,the21RainfallAmount(cont.)Additionalconsiderationsdetermininghowmuchrainwillfallinclude:Howmuchmoistureisavailable?Willtheprecipitationbeconvectiveornot?Willcellstrainoverthesameareaornot?Willnewstormsformorcontinuetoformupstream?(regeneration)Willaboundaryorlocaltopographyprovidelocalenhancement?RainfallAmount(cont.)Additio22FlashFloodThreatfromWeaklyshearedCellsRainfallcontributionstotheflashfloodthreatare:therainfallrate,anditsduration.Rainfallrateisdependenton:theupwardmoistureflux,andespecially,precipitationefficiencyFlashFloodThreatfromWeakly23FlashfloodthreatfromweaklyshearedcellsUpwardmoisturefluxdependsonUpdraftstrengthMoisturecontentofairenteringupdraftPrecipitationefficiencyisthefractionoftotalmoistureingestedbytheupdraftthatfallsbacktothegroundasrainfall.Environmentsfavoringhighprecipitationefficiencyaremostlikelyassociatedwithflashfloodreports Flashfloodthreatfromweakly24FlashfloodthreatfromweaklyshearedcellsFavorableconditionsforhighprecipitationefficiency:Highmid-levelrelativehumidity(littledryentrainment)Deepwarmcloudlayer(increasewarmcollisioncoalescencemicrophysics)Wideupdrafts(reducedryentrainment)SeedingFlashfloodthreatfromweakly25BasicprinciplesChappell’sLaw-Part1Rainfallrate,R

EwqE=precipitationefficiencyw=ascentrateq=watervapormixingratioBasicprinciplesChappell’sLaw26EffiencyschematicEffiencyschematic27Whatcontrolsefficiency?EvaporationofcondensedwaterEnvironmentalhumidityWindshearExportationofcondensedwaterintoanvil,typicallyintheformoficeMultiplecellsEarlycellsmaybeinefficientLatercellsdevelopinanewenvironmentspectrumofclouddropletsizesLargerarealcoverageofMPSWhatcontrolsefficiency?Evapo28FlashfloodthreatfromweaklyshearedcellsWarmclouddepthincreasescollisioncoalescenceresultinginexcessiverainfallratesStormtopmaynotbehighFlashfloodthreatfromweakly29FlashfloodthreatfromweaklyshearedcellsAsignatureofadeepwarmcloudLookforsignificantincreaseinreflectivityfromthefreezingleveldowntotheLCLRadarwillunderestimaterainfallpotentialofthesestormsifbeamrisesabovetheLCLFlashfloodthreatfromweakly30Warm-rain-process-convection暖雨過程對流課件3117:53BST0.5°reflectivity(yellowthinlinerepresentthepositionofverticalcrosssection)17:53BST0.5°reflect3217:53BST17:53BST33Thesooneryoucankeyinonwarmrainprocessdominatedconvection,thequickeryoucanswitchtotropicalZ/Randhelpdetectflashflood-producingrainAnticipatingDominantWarmRainProcessConvectionEnvironmentalassessmentismostimportant,thensupplementwithreal-timedatasignaturesThesooneryoucankeyinonw34AssesstheenvironmentAssesstheenvironment35Jinan2007071808Jinan200707180836Jinan2007071814Jinan200707181437Jinan2007071820Jinan200707182038Xintai2007071808Xintai200707180839Zhengzhou2007071808Zhengzhou200707180840ComparisonofwarmrainconvectionwithintenseconvectionComparisonofwarmrainconvec41WarmRainProcesses

Real-TimeDataSignaturesLookforreflectivitystructures,satellite,andlightningdataHighreflectivityconcentratedbelowthein-cloudfreezinglevel(lowechocentroid)IRSatellite:Cloudtops“warm”LackofsignificantlightningWarmRainProcesses

Real-Time42WarmRainProcesses

RadarSignaturesKansasTurnpikeFlashFloodAug30,2003LECWarmRainProcesses

RadarSign4317:53BST0.5°reflectivity(yellowthinlinerepresentthepositionofverticalcrosssection)17:53BST0.5°reflect4417:53BST17:53BST45Warm-rain-process-convection暖雨過程對流課件46對流單體6時04分和6時10分剖面圖對流單體6時04分和6時10分剖面圖47Warm-rain-process-convection暖雨過程對流課件48Warm-rain-process-convection暖雨過程對流課件49Warm-rain-process-convection暖雨過程對流課件50Warm-rain-process-convection暖雨過程對流課件51WarmRainProcesses

ARecentExampleWarmRainProcesses

ARecentE52CrossSectionthroughWarm-RainSupercellCrossSectionthroughWarm-Rai53Warm-rain-process-convection暖雨過程對流課件54Warm-rain-process-convection暖雨過程對流課件55Warm-rain-process-convection暖雨過程對流課件56BasicprincipleChappell’sLaw-Part2DurationoftherainfallSizeoftherainfall“footprint”SpeedofmovementoftherainfallareaNotthesameasstormmovement!IndividualconvectivecellscanmovethroughaconvectivesystemBasicprincipleChappell’sLaw57DurationandintensityofrainDurationandintensityofrain58Warm-rain-process-convection暖雨過程對流課件591.0度速度圖1.0度速度圖60FlashfloodthreatfromweaklyshearedcellsFF-typedurationscanresultfromindividualstormsthathave:Slowmovement(<10kts)Largeareasofhighrainfallratesalongthemotionvector,celltraining,orAlloftheseFlashfloodthreatfromweakly61Rainfalldurationsfromindividualstormsdependon;(1)slowmovementand(2)largeareaofhighrainfallrates.Rainfalldurationsfromindivi62Warm-rain-process-convection暖雨過程對流課件63Warm-rain-process-convection暖雨過程對流課件64070021.01.27.591070021.02.27.591070021.01.19.591070021.02.19.591070021.03.27.591070021.03.19.591070021.00.37.591070021.00.41.591070021.00.57.591070021.01.27.591070021.02.27.565072422.01.27.591072422.02.27.591072422.01.19.591072422.02.19.591072422.03.27.591072422.03.19.591072422.00.37.591072422.00.41.591072422.00.57.591072422.01.27.591072422.02.27.566074206.01.27.591074206.02.27.591074206.01.19.591074206.02.19.591074206.03.27.591074206.03.19.591074206.00.37.591074206.00.41.591074206.00.57.591074206.01.27.591074206.02.27.567075355.01.27.591075355.02.27.591075355.01.19.591075355.02.19.591075355.03.27.591075355.03.19.591075355.00.37.591075355.00.41.591075355.00.57.591075355.01.27.591075355.02.27.568081703.01.27.591081703.02.27.591081703.01.19.591081703.02.19.591081703.03.27.591081703.03.19.591081703.00.37.591081703.00.41.591081703.00.57.591081703.01.27.591081703.02.27.569Warm-rain-process-convection暖雨過程對流課件70Warm-rain-process-convection暖雨過程對流課件71FlashfloodproducingconvectionSustainedconvectionisalwaysmulticellularSupercellstypicallyarenotefficientOftenmoverapidlySheared,highkineticenergyenvironments,oftenwithdeeplayersoflowhumidityabovetheboundarylayerNonsupercellstorms-bothdiscreteandlinearlyorganizedFlashfloodproducingconvecti72“CellTraining”PRODUCESASEQUENCEOFCELLS,REPEATEDLYPASSINGOVERTHESAMEAREA“CellTraining”PRODUCESASEQU73CellTrainingorRegenerationFactorsthatcanleadtoechotrainingorregenerationinthesameareainclude:Aslowmovinglow-levelboundaryorfrontAquasi-stationaryLLJAquasi-stationaryareaofupper-leveldivergenceAlow-levelboundaryalmostparalleltothemeanflow(sourceofmoistureconvergence)AlackofstrongverticalwindshearCellTrainingorRegenerationF74Warm-rain-process-convection暖雨過程對流課件75Trainingecho

76Warm-rain-process-convection暖雨過程對流課件77Warm-rain-process-convection暖雨過程對流課件78Warm-rain-process-convection暖雨過程對流課件79Warm-rain-process-convection暖雨過程對流課件80Warm-rain-process-convection暖雨過程對流課件81Warm-rain-process-convection暖雨過程對流課件82Warm-rain-process-convection暖雨過程對流課件83Warm-rain-process-convection暖雨過程對流課件84Warm-rain-process-convection暖雨過程對流課件85Warm-rain-process-convection暖雨過程對流課件86Warm-rain-process-convection暖雨過程對流課件87Warm-rain-process-convection暖雨過程對流課件88Warm-rain-process-convection暖雨過程對流課件89Warm-rain-process-convection暖雨過程對流課件90Warm-rain-process-convection暖雨過程對流課件91TrainingechoTrainingecho92SystemMovementNotsurprisingly,slowmovingsystemsusuallyproducetheheaviestrainfall!Forveryshort-termforecasts,extrapolationbasedonradarandsatelliteprovideprimaryguidanceForlongertermforecasts,modelsprovidedecentguidanceButyoustillneedtoconsidermodelcharacteristicsandlimitationsSystemMovementNotsurprisingl93CellMovementandPropagationSystemmovementdependsoncellmovementandpropagationIndividualconvectivecellsusuallymoveataround90%ofthemeanwindwithaslightdeviationtotherightPropagationisaffectedbyhowfastnewcellsformalongsomeflankofthesystemCellMovementandPropagationS94UsingRadarImagery(cont.)AnimatingimageryisusefulforDeterminingcell/systemmovementDeterminingifcellsaretrainingUsingRadarImagery(cont.)Ani95Warm-rain-process-convection暖雨過程對流課件96DiscussionQuestion

Whataresomeoftheradarlimitationsthatcanadverselyimpactyourdecisionmakingduringaheavyprecipitationevent?

AttenuationAnomalousPropagation(AP)–beampropagationRange–radarhorizonGroundclutterPoorcalibrationBeamblockageImproperZ/Rrelationship(algorithm)Hailcontamination(algorithm)BelowbeamaffectsBrightbandcontaminationPowerfailure,equipmentfailure

DiscussionQuestion Whatare97RainfallEstimationLimitationsBrightbandContaminationRadarCenteredArchofHigherRainfallAccumulationsonprouduct.OverestimaterainfallButraretoaffectconvectiveflashfloodingeventsRainfallEstimationLimitation98RainfallEstimationLimitationsHailContamination

cansignificantlyoverestimaterainfall,especiallyforhigh-endhailstormsliketheoneontherightRainfallEstimationLimitation99RainfallEstimationLimitationsDistancefromRadarHeightofreflectivityusedforcalculationmaybeHundredsoffeetOver10,000feetRainfallEstimationLimitation100RainfallEstimationLimitationsInaccurateZ/RrelationshipduetoestimationofdropsizedistributionsSameReflectivity,

VastlyDifferentRainratesRainfallEstimationLimitation101DefaultZ-RrelationshipinTropicalregionForwarmrainprocessconvection,thebestZ-RrelationisZ=230*R(1.25).ComparingZ-Rrelations.40dBz45dBz50dBzZ=300*R(1.4)12mm/h28mm/h62mm/hZ=230R(1.25)20mm/h50mm/h130mm/hItisseenfromabovecomparisonthatZ=300*R(1.4)ismuchunderestimationofheavyprecipitation.DefaultZ-RrelationshipinTr102ConditionforwarmrainprocessconvectionEnvironmentcondition:Veryhighprecipitatablewater(PW),ThinCAPE,Absenceofdryairatanylever,Lowwindshear,Verydeepwarmclouddepth,etc.Conditionforwarmrainproces1031小時累積降水(OHP78)1小時累積降水(OHP78)1043小時累積降水(THP79)3小時累積降水(THP79)105CorrectingOHPandTHPproductaccordingtodifferentZ—RrelationshipZ=230*R(1.25)CorrectingOHPandTHPproduct106THEENDThankyouTHEENDThankyou107HeavyrainfallandflashfloodHeavyrainfallandflashflood108Warm-rain-process-convection暖雨過程對流課件109FlashFloodsFlashfloodsarethenumberoneweather-relatedkillerinovermuchoftheglobeNearlyhalfofallflashfloodfatalitiesareautorelatedFlashFloodsFlashfloodsaret110Warm-rain-process-convection暖雨過程對流課件111FlashFloodDefinitionIntensePrecipitationSmallfast-responsebasins“Asituationwherethecausativeprecipitationandthesubsequentrunoffareoccurringonthesamescales.”

NATOAdvancedStudyInstitute(1999)FlashFloodDefinitionIntense112FlashfloodforecastingTheflashflood-aprototypicalhydro-meteorologicaltopicAmeteorologicalevent:rainfallAhydrologicalsettingBasinresponsetimesRunoffcharacteristicsWorkingwithhydrologists?Flashflood“guidance”isanestimateoftherainfallneededforflashfloodingtooccurFlashfloodforecastingThefla113FloodconsiderationsLargeriversliketheYangtzerespondtotherainfalloveraperiodofdaysFlashfloods-responsetorainfallisveryrapid:periodofperhaps10sofminutesSmallbasinsincomplexterrainarethosemostlikelytohaveflashfloodsUrbanfloodingcanhaveimportantimpacts-highrunoff.FloodconsiderationsLargerive11420070718JinanFlashFloodingEventJinanisthecapitalcityofShandongprovince.During12hperiodfrom14:00BST(BeijingStandardTime)18Julyto02:00BST19July2007,theaveragerainfallfrom123weatherstationsforwholeShandongprovinceis62mm.Itscapitalcity,Jinan,hasexperiencedmostsevererainfall.The12hrainfallindowntownareais140mm,mostoftherainfallwasprecipitatedduring3hperiodfrom17:20to20:20BSTon18July2007.25peoplewerekilledbytheflashfloodinginJinancity.20070718JinanFlashFlooding115AFFForecastingstrategyObtainflashfloodguidancefromhydrologists:theminimumrainfallperunittimeneededfortheoccurrenceofaflashfloodBeginwiththequestion:“Whatistheprobabilityofrainfallapproachingthatvaluetoday?”AFFForecastingstrategyObtai116Precipitationin

FlashFloodsAccumulation5-50cmover1-12hoursDurationMostlylessthan3hoursIntensity

Arid/semi-aridclimates7.5-20cm/hour(avg.11.5cm/hour)Humidclimates12.5-30cm/hour(avg.19cm/hour)CourtesyMattKelschPrecipitationin

FlashFloods117Precipitationin

FlashFloodsEnhancedIntensityPrecipitationefficiencyTropical,maritimeconnectionDeep,above-freezinglayerLow-leveljet,rapidmoisturereplenishmentLow-levelfocus(terrainandboundary)/class/FLOAT_2001/index.htmPrecipitationin

FlashFloods118ThelowleverjetThelowleverjet119ThelowleveljetThelowleveljet120ThelowleveljetfromsouthwestThelowleveljetfromsouthwe121LowleveljetfromeastandmiddleleveljetfromsouthwestLowleveljetfromeastandmi122BasinCharacteristics

inFlashFloodsSmall9-150km2(avg.55km2)70%mountainouswatersheds>50%alteredUrbanizationDeforestation,firescarsThin/impermeablesurfacelayer,Clay,rocks(lowinfiltration)Pavement(noinfiltration)Or,thick,saturatedsoillayersCourtesyMattKelschBasinCharacteristics

inFlash123FlashFloodForecastingInsomecasesthehydrologyisthedrivingforce,andsignificantflashfloodscanhappenwithunimpressiverainfall.“FlashFloodforecastingrequiresmorethanaccurateforecastsofexcessiveaccumulation.”

-MattKelsch(2000)FlashFloodForecastingInsome124FlashFloodForecastingKnowrunoffcharacteristicsSmall,fast-responsebasinsUrbanbasinsDeforestationandfirescarareas.HailremainingonedayafterCheyenne,WYflashfloodof

1August1984FlashFloodForecastingKnowru125FlashFloodForecastingKnowledgeofrelationshipofstormspeedanddirectiontostreamflowcanbecriticalFlashFloodForecastingKnowled126FlashfloodforecastingWhathappenstothewateronthegroundisjustasimportant,andinsomecasesmoreimportant.Knowyourbasins!Flashfloodforecasting127RainfallAmountBasically,theamountofrainfallthatfallsoveranareadependson:TheINTENSITYoftherainfallTheSIZEoftherainfallareaThePROPAGATIONoftherainfallareaRainfallAmountBasically,the128RainfallAmount(cont.)Additionalconsiderationsdetermininghowmuchrainwillfallinclude:Howmuchmoistureisavailable?Willtheprecipitationbeconvectiveornot?Willcellstrainoverthesameareaornot?Willnewstormsformorcontinuetoformupstream?(regeneration)Willaboundaryorlocaltopographyprovidelocalenhancement?RainfallAmount(cont.)Additio129FlashFloodThreatfromWeaklyshearedCellsRainfallcontributionstotheflashfloodthreatare:therainfallrate,anditsduration.Rainfallrateisdependenton:theupwardmoistureflux,andespecially,precipitationefficiencyFlashFloodThreatfromWeakly130FlashfloodthreatfromweaklyshearedcellsUpwardmoisturefluxdependsonUpdraftstrengthMoisturecontentofairenteringupdraftPrecipitationefficiencyisthefractionoftotalmoistureingestedbytheupdraftthatfallsbacktothegroundasrainfall.Environmentsfavoringhighprecipitationefficiencyaremostlikelyassociatedwithflashfloodreports Flashfloodthreatfromweakly131FlashfloodthreatfromweaklyshearedcellsFavorableconditionsforhighprecipitationefficiency:Highmid-levelrelativehumidity(littledryentrainment)Deepwarmcloudlayer(increasewarmcollisioncoalescencemicrophysics)Wideupdrafts(reducedryentrainment)SeedingFlashfloodthreatfromweakly132BasicprinciplesChappell’sLaw-Part1Rainfallrate,R

EwqE=precipitationefficiencyw=ascentrateq=watervapormixingratioBasicprinciplesChappell’sLaw133EffiencyschematicEffiencyschematic134Whatcontrolsefficiency?EvaporationofcondensedwaterEnvironmentalhumidityWindshearExportationofcondensedwaterintoanvil,typicallyintheformoficeMultiplecellsEarlycellsmaybeinefficientLatercellsdevelopinanewenvironmentspectrumofclouddropletsizesLargerarealcoverageofMPSWhatcontrolsefficiency?Evapo135FlashfloodthreatfromweaklyshearedcellsWarmclouddepthincreasescollisioncoalescenceresultinginexcessiverainfallratesStormtopmaynotbehighFlashfloodthreatfromweakly136FlashfloodthreatfromweaklyshearedcellsAsignatureofadeepwarmcloudLookforsignificantincreaseinreflectivityfromthefreezingleveldowntotheLCLRadarwillunderestimaterainfallpotentialofthesestormsifbeamrisesabovetheLCLFlashfloodthreatfromweakly137Warm-rain-process-convection暖雨過程對流課件13817:53BST0.5°reflectivity(yellowthinlinerepresentthepositionofverticalcrosssection)17:53BST0.5°reflect13917:53BST17:53BST140Thesooneryoucankeyinonwarmrainprocessdominatedconvection,thequickeryoucanswitchtotropicalZ/Randhelpdetectflashflood-producingrainAnticipatingDominantWarmRainProcessConvectionEnvironmentalassessmentismostimportant,thensupplementwithreal-timedatasignaturesThesooneryoucankeyinonw141AssesstheenvironmentAssesstheenvironment142Jinan2007071808Jinan2007071808143Jinan2007071814Jinan2007071814144Jinan2007071820Jinan2007071820145Xintai2007071808Xintai2007071808146Zhengzhou2007071808Zhengzhou2007071808147ComparisonofwarmrainconvectionwithintenseconvectionComparisonofwarmrainconvec148WarmRainProcesses

Real-TimeDataSignaturesLookforreflectivitystructures,satellite,andlightningdataHighreflectivityconcentratedbelowthein-cloudfreezinglevel(lowechocentroid)IRSatellite:Cloudtops“warm”LackofsignificantlightningWarmRainProcesses

Real-Time149WarmRainProcesses

RadarSignaturesKansasTurnpikeFlashFloodAug30,2003LECWarmRainProcesses

RadarSign15017:53BST0.5°reflectivity(yellowthinlinerepresentthepositionofverticalcrosssection)17:53BST0.5°reflect15117:53BST17:53BST152Warm-rain-process-convection暖雨過程對流課件153對流單體6時04分和6時10分剖面圖對流單體6時04分和6時10分剖面圖154Warm-rain-process-convection暖雨過程對流課件155Warm-rain-process-convection暖雨過程對流課件156Warm-rain-process-convection暖雨過程對流課件157Warm-rain-process-convection暖雨過程對流課件158WarmRainProcesses

ARecentExampleWarmRainProcesses

ARecentE159CrossSectionthroughWarm-RainSupercellCrossSectionthroughWarm-Rai160Warm-rain-process-convection暖雨過程對流課件161Warm-rain-process-convection暖雨過程對流課件162Warm-rain-process-convection暖雨過程對流課件163BasicprincipleChappell’sLaw-Part2DurationoftherainfallSizeoftherainfall“footprint”SpeedofmovementoftherainfallareaNotthesameasstormmovement!IndividualconvectivecellscanmovethroughaconvectivesystemBasicprincipleChappell’sLaw164DurationandintensityofrainDurationandintensityofrain165Warm-rain-process-convection暖雨過程對流課件1661.0度速度圖1.0度速度圖167FlashfloodthreatfromweaklyshearedcellsFF-typedurationscanresultfromindividualstormsthathave:Slowmovement(<10kts)Largeareasofhighrainfallratesalongthemotionvector,celltraining,orAlloftheseFlashfloodthreatfromweakly168Rainfalldurationsfromindividualstormsdependon;(1)slowmovementand(2)largeareaofhighrainfallrates.Rainfalldurationsfromindivi169Warm-rain-process-convection暖雨過程對流課件170Warm-rain-process-convection暖雨過程對流課件171070021.01.27.591070021.02.27.591070021.01.19.591070021.02.19.591070021.03.27.591070021.03.19.591070021.00.37.591070021.00.41.591070021.00.57.591070021.01.27.591070021.02.27.5172072422.01.27.591072422.02.27.591072422.01.19.591072422.02.19.591072422.03.27.591072422.03.19.591072422.00.37.591072422.00.41.591072422.00.57.591072422.01.27.591072422.02.27.5173074206.01.27.591074206.02.27.591074206.01.19.591074206.02.19.591074206.03.27.591074206.03.19.591074206.00.37.591074206.00.41.591074206.00.57.591074206.01.27.591074206.02.27.5174075355.01.27.591075355.02.27.591075355.01.19.591075355.02.19.591075355.03.27.591075355.03.19.591075355.00.37.591075355.00.41.591075355.00.57.591075355.01.27.591075355.02.27.5175081703.01.27.591081703.02.27.591081703.01.19.591081703.02.19.591081703.03.27.591081703.03.19.591081703.00.37.591081703.00.41.591081703.00.57.591081703.01.27.591081703.02.27.5176Warm-rain-process-convection暖雨過程對流課件177Warm-rain-process-convection暖雨過程對流課件178FlashfloodproducingconvectionSustainedconvectionisalwaysmulticellularSupercellstypicallyarenotefficientOftenmoverapidlySheared,highkineticenergyenvironments,oftenwithdeeplayersoflowhumidityabovetheboundarylayerNonsupercellstorms-bothdiscreteandlinearlyorganizedFlashfloodproducingconvecti179“CellTraining”PRODUCESASEQUENCEOFCELLS,REPEATEDLYPASSINGOVERTHESAMEAREA“CellTraining”PRODUCESASEQU180CellTrainingorRegenerationFactorsthatcanleadtoechotrainingorregenerationinthesameareainclude:Aslowmovinglow-levelboundaryorfrontAquasi-stationaryLLJAquasi-stationaryareaofupper-leveldivergenceAlow-levelboundaryalmostparalleltothemeanflow(sourceofmoistureconvergence)AlackofstrongverticalwindshearCellTrainingorRegenerationF181Warm-rain-process-convection暖雨過程對流課件182Trainingecho

183Warm-rain-process-convection暖雨過程對流課件184Warm-rain-process-convection暖雨過程對流課件185Warm-rain-proc