upper atmosphere studies lecture上層大氣研究講座

MamoruYamamotoRISH,KyotoUniversity,JapanIonosphereirregularitiesISWISchool2012Puncak,IndonesiaSeptember20,2012Tropopause10StructureoftheEarth’satmosphereThermosphere

(ionosphere)

above90kmMesosphere

50–90kmStratosphere

12–50kmTroposphere

0–12kmTemperatureHeightUpper

atmosphereMiddle

atmosphereLower

atmosphereContentsMid-andlow-latitudeionosphereobservations.VerticalcouplingoftheEarth’satmosphere.1sttopic:EquatorialSpread-F(Plasmabubble)ObservationsandphenomenaGrowthrate,seedingmechanisms,etc.2ndtopic:IrregularityintheE-regionTwo-streamandgradient-driftinstabilityPhenomenainmid-latitudeionosphereTextbookM.C.KelleywithR.A.Heelis,TheEarth'sIonosphere:PlasmaPhysicsandElectrodynamics(InternationalGeophysicsSeries),AcademicPress,SanDiego,October1989.(2ndeditionofMay2009isavailable:ISBN-13978-)SpaceWeatherandEarth’sinfluenceSpaceweatherisaprogramtoobserve,assess,andforecastthespaceenvironment,whichisveryimportantforconstantoperationofsatellitesystemsandreliablecommunication/navigationpurposes.NotonlythestudyoftheSun-to-Earthsystem,butalsostudiesofverticalcouplingoftheatmosphere/ionosphereisimportant.Regionalobservations(especiallyinthelowlatitudes)arethusnecessary.NoisydatatransformfrommeteorologicalsatellitesonlyoccursoverAsia.Satellitesignalisscintillatedbythedisturbanceoftheionosphere.電離圏(高度300km中心)Ionosphere(about300kmhigh)Spaceweather:studyofnear-EarthspaceenvironmentIonosphereistheheightrangeforISSandSpaceShuttleAtmospherewavesgeneratedbyconvectionactivitiesStratosphere(19-26km)waveenergyJune–August,2004Dec.2004–Feb.2005Tropopause

(-15km)cloud-toptemperature対流圏內(nèi)の活発な積雲(yún)対流と成層圏の大気波動(dòng)の活動(dòng)度増大が一致する対流圏の積雲(yún)対流の増大につれて、成層圏の大気波動(dòng)の活動(dòng)度が増大する。この関係は季節(jié)に寄らず成り立つ。対流圏の積雲(yún)対流の増大につれて、成層圏の大気波動(dòng)の活動(dòng)度が増大する。この関係は季節(jié)に寄らず成り立つ。Convectioninthetroposphereandatmosphericwavesinthestratospherearewellcorrelate.Zonalwind:RadiosondeatSingaporeZonalwind:MFradarinTirunelveli,IndiaQuasiBiannialOci.（QBO）SemiannualOsci.（SAO）StratosphericQBO

andmesosphericSAOshowintensivecorrelation(anotherverticalcouplingwithatmosphericwaves)Mesosphere86-94kmStratosphere20-40kmLocatedatKototabang,WestSumatra,Indonesia(0.20°S,100.32°E)Operatedsince2001underclosecollaborationbetweenRISHandLAPANEquatorialAtmosphereRadar(EAR)Antennafield(110mindiameter)47MHz,100kW,560YagiantennasPiuraJicamarcaMUEARGadankiTrivandrum※EAR:EquatorialAtmosphereRadar(locatedrightatthegeographicequatorandinthegeomagneticsouthernhemisphere)dipequatorALTAIRVHFRadarsintheLow-LatitudeRegionJicamarcaradarinPeruObservationfacilitiesattheEARsiteMicro-rainradarCeilometerDisdrometerOpticalraingausgeRadiometerRASSX-bandradarGPSReceiverImagerVHFRadarLidarEARRXsystemEARFM-CWRadarMeteorRadarObservationNetworkSEALION(byNICT)SoutheastAsiaEquatorialIonosphericNetworkNetworkofFM-CWionosondesNICT=NationalInstituteofInformationandCommunicationsTechnologyIonosondesitesKototabang(=EARsite)Chumphon(Thailand)

(closetothegeomagneticequator)ChiangMai(Thailand)(B-fieldconjugatetotheEARsite)PhuThuy(Vietnam)BacLieu(Vietnam)EARsiteSEALIONionosondeObservationNetworkSEALION(byNICT)SoutheastAsiaEquatorialIonosphericNetworkNetworkofFM-CWionosondesNICT=NationalInstituteofInformationandCommunicationsTechnologyIonosondesitesKototabang(=EARsite)Chumphon(Thailand)

(closetothegeomagneticequator)ChiangMai(Thailand)(B-fieldconjugatetotheEARsite)PhuThuy(Vietnam)BacLieu(Vietnam)EARsiteSEALIONionosondeOPTICALINSTRUMENTSChiangMai

Airglowimager(NICT)

F-PInterferometer(STEL)Kototabang

Airglowimager(STEL)

F-PInterferometer(STEL)OtherRADARSKototabang

30MHzFAIRadar(STEL)

Meteorradar(RISH)F-regiondynamoineveningNeutralwindintheeveningisnaturallyeastward(withlargevariability).Thissetspositive/negativechargesatthetop/bottomsideofF-region.(GoverningconditionisJz=0)VerticaldriftofequatorialionospherePre-reversalenhancement(PRE)

/Postsunsetrise(PSR)

mechanism1sttopic:EquatorialSpread-F(ESF)

JicamarcaVHFradarobs.F-regionFieldAlignedIrregularity(FAI)Echoes

fromtheEAR

Altitude-TimeIntensity(ATI)plotIntenseFAIechoesassociatedwithplasmabubbleswereobservedfromtheEARsouthwardbeamsoonaftertheF-regionsunset.Maximumaltitudeoftheechoesreached800km.S.Fukao,Y.Ozawa,T.Yokoyama,M.Yamamoto,andR.T.Tsunoda,

J.Geophys.Res.,109,A02304,2004.Kototabang(EAR)

March18,2011IonogramRadarechoSpreadF-layertrace:ESFatlocaltime9PMESFoccurrencejustafterthesunset

(EARresultsfromFukaoetal.,2004)EARMultipleBeamObservationofESFGrowingFAITerminatorSOUTHEASTWESTEastwardpropagationofFAIechoingregionisclearlyseen.GrowingFAIsweredetectedintheobservationregionwith11beamdirections.MotionofzonalstructureofplasmabubblesobservedbyEARESFanddensitydepletionDynamicspectrumofESFdensityPlasmaBubblesObservedwithAirglowImagers

atConjugatePointsObservationbyProf.OgawagroupSTELab.,NagoyaUniv.DarwinSataMagneticEquatorPlasmaBubbleSataDarwinNovember12,2001CountCountOtsuka,Y.,K.Shiokawa,T.Ogawa,andP.Wilkinson,Geophys.Res.Lett.,29(15),10.1029/2002GL015347,2002.Shiokawa,K.,Y.Otsuka,T.Ogawa,andP.Wilkinson,Ann.Geophysicae,inpress,2004.SataEARsiteImagerPhotometerGPSreceiverImagerMagneticEquatorDarwinImagerLong.Long.EquatorialSpread-F(ESF)Localdensity-depletedregionsatthebottomsideoftheionospheredevelopandrapidlymoveupwardtothetopsideoftheionosphere.Rayleigh-Taylorinstabilityisthemechanism.ESFoccursmainlynearF-regionsunsetoverthemagneticequator.Meridionallyelongatedstructurealongthefieldline.paniedwithsmall-scaleirregularitiesthataredetectablebyVHFradars.DevelopmentofplasmabubblesMeridionalstructureofplasmabubblesDensity:highDensity:lowGeomagneticfieldMag.EQPlasmabubbleIonosophere100km1000kmConceptofRayleigh-TaylorinstabilityTheoryofESFESFisconsideredasRayleigh-TaylorinstabilityoccurringatthebottomsideoftheF-region.Governingequationsare,

wheren,t,V,aredensity,time,andvelocityvector.J=Vi

-Ve

iscurrentvector.GenerationofthepolarizationelectricfieldE’isessentialforstabilityoftheplasma.TheoryofESFLineargrowthrateofR-Tinstabilityisthen,

where

R-Tinstabilityisunstablebygravity(term1)andambienteastwardelectricfield(term2).Term1showsthatsmallcollision(=highionosphere)isfavorablefortheinstability.Term2showsthatelectricfieldbystorminitiatesESF.R-Tinstabilitymaybegeneratedbyeastwardordownwardcomponentoftheneutralwind.OccurrenceandvariabilityofESFFukaoetal.,2006ESFsmainlyoccurafterthelocalsunsetpreiod.Thisisexplainedbypost-sunsetrise(PSR,orpre-reversalenhancement(PRE))thatistheelectromagneticbehavioroftheionosphereatthesunsetterminator.Ifso,whyESFshowlargeday-to-dayvariability.Large-ScaleWaveStructure(LSWS)isconsideredasakeytothisproblem.LSWSmeasuredwith630nmimager

(Makelaetal,GRL,2010)LongitudinaldistributionofESFCasestudyonMarch24,2004Average：690km(S.D.：180km)Minimum：370kmMaximum：1000kmPossiblemodulationofESF

owingtogravitywaves.Distance：~500kminaverageSpatialintervalbetweenESFA-DFourregionsofESF(A、B、C、D)wereobservedduring20-0LTTypicalinterval

betweenESFclusters(16cases)Fukaoetal.,20062ndtopic:instabilitiesintheEquatorialelectrojet(orE-region)FAIintheelectrojet(Type1)

JicamarcaVHFradarobs.FAIintheelectrojet(Type2)

JicamarcaVHFradarobs.FiguretitleDopplershiftofelectrojetFAIechoesRocketexperimentofelectrojetFAILineartheoryoftheE-regionFAI(1)LineartheoryofE-regionFAI(Fejer,etal.,1975)GrowthratewhereFromthiswecaninfertwoinstabilitiesoftwokinds.Two-streaminstability(relatedterm1=Type1)occurswhenelectronsrunthroughionsatfasterspeedthanthesoundspeed,

Thisoccursmainlyintheelectrojetorlimitedconditionswhereintenseambientelectricfieldapply.RadarechoshowDopplerfrequencyLineartheoryoftheE-regionFAI(2)Gradient-driftinstability(relatedterm2=Type2)occurswhenintensedensitygradientexistsandsomeelectricfield(orneutralwind)isapplied.RadarechoshowsfollowingDopplershiftof

whereisneutralwindcomponentperpendiculartothegeomagenticfield.Asisnegligible(~0)abovearound100km,FAIechoesshowExBdriftofplasmaintheregion.Below100kmconsiderationoftheneutralatmosphereisnecessary.LineartheoryoftheE-regionFAI(3)Two-streaminstabilityGradient-driftinstabilityEarlierobservationswiththeMUradar(Shigaraki,Japan)Mid-latitudeE-regionFAIYamamotoetal.,1991IntenseechoesaftersunsetperiodQuasi-PeriodicEchoWeakechoaftersunriseContinuousecho43Close-upofeveningechoesYamamotoetal.,1991Mid-latitudeE-regionFAIEarlierobservationswiththeMUradar(Shigaraki,Japan)44Horizontalstructureofmid-latitudeE-regionFAIMUradar+FrequencyAgileRadarsimultaneousobs.Yamamotoetal.,199745F-regionMedium-ScaleTravelingIonosphericDisturbance(MSTID)GPS-TECoverJapanRedairglow(630nm)overJapan46E-regionandF-regionechoesarewellco-locatedwhenmappedalongtheB-field.Bothechoespropagatedtothewestorsouthwestwithsimilarphasevelocity.June18,2004(casefromFERIX-1)SummaryIonosphereIrregularityIrregularitiesaredrivenbypolarizationelectricfiledthatarisesfromplasma-densityvariation¤tcontinuity.Largerangeofscales:severalmetersto100km.ESForplasmabubbleOccurafterequatorialF-regionsunset.AlsogeneratedbymagneticstormsUnderstoodbyR-Tinstability,butseedingmechanismisnotfullyunderstood.E-regionFAIType1and2instabilitiesarewellknown.Type2areseeninthemid-latituderegion.CouplingwiththeneutralatmosphereVerticalcouplingoftheEarth’satmosphereisimportant.EquatorialelectrojetFiguretitleFiguretitleE-regionFAIexperimentwithMUradarQPechoes(severalminutes)appearaftersummersunsetperiod.Echoenhancementslooktohaveslowervariationofabout~1hour.Yamamotoetal.,1991Location:Kototabang,WestSumatra,Indonesia(0.20°S,100.32°E)EquatorialAtmosphereRadar(EAR)Antennafield(110mindiameter)100kW,560YagiantennasInteractionsbetweentheLowerandUpperAtmosphereovertheEquatorialRegionTheequatorialatmospherefeaturedby:MaximuminputofsolarradiationMinimumCorioliseffectHorizontalgeomagneticfieldTroposphereStratosphereMesosphereThermosphere/IonosphereTemperatureprofileMeridionalAtmosphericMotionsTroposphereMesosphereStratosphereThermosphere/IonosphereInteractionsbetweentheLowerandUpper

AtmosphereovertheEquatorialRegionEARlong-periodexperimentEARcontinueslong-periodcontinuousobservationssinceJune2001.Mostofthemwereforwindmeasurementofthetroposphereandstratosphere.FromJuly2010,weshifttheobservationmodetomoreionospherestudiesowingtothecurrentresearchprogramof“IndonesiaSpaceWeather”WindmeasurementContinuousionospheremeasurementstartedinJuly2010Tsunodaetal,2005LargeScaleWaveStructure(LSWS)LSWS:Zonalstructureofionospherewithwavelengthof~500kmShowgoodcorrelationwi