Ionosphere response to solar wind high-speed streams

We present 9- and 7-day periodic oscillations in the global mean Total Electron Content (TEC) from 1 January 2005 to 31 December 2006. Spectral analysis indicates that the pronounced periodicities of 9 and 7 days observed in TEC are associated with variations in solar wind high-speed streams and geomagnetic activity. Neutral temperature and winds near 250 km, measured by a Fabry-Perot Interferometer at Resolute Bay, also exhibit 9- and 7-day periodicities. These pronounced periodicities support simultaneous observations of 9- and 7-day periodicities in thermosphere neutral density (Lei et al., 2008a; Thayer et al., 2008). It is anticipated that the ionospheric response at 9 and 7 days represents some combination of effects due to chemical loss, neutral winds, and disturbance dynamodriven electric fields.