Thermospheric response to periodic variation in solar wind and tidal force

Using measurements from ACE and TIMED/GUVI in 2005, we established a link among the dayside magnetic merging rate (MMR), auroral hemispheric power (HP), thermospheric neutral density and temperature as all of them showed clear 9-day variation. The magnitudes of the 9-day variation in the thermospheric temperature increased from the equator (|latitude| < 30) to the mid-latitude (30< |latitude| < 45) and reached their peak values in high latitudes (45< |latitude| < 90). In addition to the MMR, atmospheric tides also affect the thermospheric density and composition. Yearly average maps of GUVI nadir O/N2 from 2002 to 2009 revealed wave-3 type variations at mid-low latitudes. The wave patterns are roughly the same and fixed in the geographic coordinates. The GUVI O/N2 maps have been compared with MSIS model O/N2 with tidal forcing on. Furthermore, the peaks of the O/N2 waves are at the same locations or longitudes of the observed wave structures in the F-region electron density. This suggests that the O/N2 wave structure could be one of the driving mechanisms that control the F-region electron density. All these features provide opportunities for developing space weather forecast tools.