A New Empirical Thermospheric Density Model JB2008 using new solar and geomagnetic indices

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1、AIAA2008-6438ANewEmpiricalThermosphericDensityModelJB2008UsingNewSolarandGeomagneticIndices*BruceR.BowmanAirForceSpaceCommandSpaceAnalysis/A9ACbruce.bowman@peterson.af.mil719-556-3710W.KentTobiskaSpaceEnvironmentTechnologiesktobiska@spacenvironment.n

2、et310-573-4185FrankA.Marcos,CherylY.Huang,ChinS.Lin,WilliamJ.BurkeAirForceResearchLaboratoryAFRL/RVBXTAFRL.RVB.PA@hanscom.af.mil781-377-3037Anewempiricalatmosphericdensitymodel,Jacchia-Bowman2008,isdevelopedasanimprovedrevisiontotheJacchia-Bowman2006

3、modelwhichisbasedonJacchia’sdiffusionequations.Drivingsolarindicesarecomputedfromon-orbitsensordataareusedforthesolarirradiancesintheextremethroughfarultraviolet,includingx-rayandLyman-αwavelengths.Newexospherictemperatureequationsaredevelopedtorepre

4、sentthethermosphericEUVandFUVheating.Newsemiannualdensityequationsbasedonmultiple81-dayaveragesolarindicesareusedtorepresentthevariationsinthesemiannualdensitycyclethatresultfromEUVheating.GeomagneticstormeffectsaremodeledusingtheDstindexasthedrivero

5、fglobaldensitychanges.Themodelisvalidatedthroughcomparisonswithaccuratedailydensitydragdatapreviouslycomputedfornumeroussatellitesinthealtituderangeof175to1000km.ModelcomparisonsarecomputedfortheJB2008,JB2006,Jacchia1970,andNRLMSIS2000models.Accelero

6、metermeasurementsfromtheCHAMPandGRACEsatellitesarealsousedtovalidatethenewgeomagneticstormequations.*ThispaperisdeclaredaworkoftheUSGovernmentandisnotsubjecttocopyrightprotectionintheUSDODDistributionA.Approvedforpublicrelease;distributionunlimited.I

7、.Introduction1UntildevelopmentoftheJacchia-Bowman2006(JB2006)modeltypicaldensitymodelerrorsontheorder2of15%-20%onestandarddeviationwererecognizedforallempiricalmodelsdevelopedsincethemid1960s.Theselargedensitystandarddeviationscorrespondtomaximumdens

8、ityerrorsofapproximately40-60%asobservedinsatellitedragdata.Therearetwomainreasonsfortheseconsistentlylargevalues.3,4Oneistheresultofnotmodelingthesemiannualdensityvariationasafunctionofsolaractivity,andtheotherresultsfromnotmodelingthefullthermosphe