VariationsofThermosphereDensityBasedonJointAnalysisofIn-SituMeasurementDataFromShenzhouSpacecrafts

BasedonthemeasurementsmadebyAtmosphericDensityDetectors(ADDs)onboardChinesespacecraftShenzhou2-4,thevariationsofthermospheredensityarerevealed.Duringthequietperiod,thedensityatspacecraftaltitudeof330～410kmexhibitedadominantdiurnalvariation,withhighvalueondaysideandlowvalueonnightside.Theratioofthediurnalmaximumdensitytotheminimumrangedfrom1.7to2.0.Theratioshowsapositivecorrelationwiththelevelofsolaractivityandanegativecorrelationwiththelevelofgeomagneticactivity.Whenageomagneticdisturbancecomes,theatmosphericdensityatthealtitudeof330～410kmdisplayedaglobalenhancement.Forastronggeomagneticdisturbance,theatmosphericdensityincreasedbyabout56%,andreacheditsmaximumabout6～7hoursafterthegeomagneticdisturbancepeak.Thedensityasymmetrywasalsoobservedbothinthesouthernandnorthernhemisphereduringthegeomagneticdisturbancepeak.