Responses of the lower thermospheric temperature to the 9 day and 13.5 day oscillations of recurrent geomagnetic activity

摘要: Responses of the lower thermospheric temperature to 9 day and 13.5 day oscillations recurrent geomagnetic activity solar EUV radiation have been investigated using neutral data observed by TIMED/SABER (Thermosphere Ionosphere Mesosphere Energetics Dynamics/Sounding Atmosphere Broadband Emission Radiometry) instrument numerical experiments NCAR-TIME-GCM (National Center for Atmospheric Research–thermosphere-ionosphere-mesosphere electrodynamics–general circulation model). The analyzed were period from 2002 2007 during declining phase cycle 23. observations show that zonal mean in thermosphere oscillated with periods near 9 13.5 days height range 100–120 km. These more strongly correlated than variability same periods. had greater amplitudes at high latitudes low latitudes; they also larger higher altitudes, could penetrate down ~105 km, depending on strength a particular time period. further periodic responses different two hemispheres. In addition, carried out investigate causal relationship between variations Model simulations showed as those seen when real index, Kp, was used drive model. results is main cause temperature, contribution minor. Furthermore, we found consecutive coronal mass ejection events long-duration enhancements strengthen signals, this kind phenomenon mostly occurred 2005