Thermosphere–ionosphere coupling in response to recurrent geomagnetic activity

The paper presents the global thermosphere–ionosphere response to the high-speed solar wind streams and the subsequent recurrent geomagnetic variations with a period of 9 d during the period of time 1 October 2007–31 March 2009. The COSMIC electron density at fixed heights, as well as the ionospheric parameters foF2 and hmF2, and the two coefficients characterizing the top and bottom side vertical gradients of the electron density profile, are used for investigating the ionospheric 9-d (s=0) wave response. The SABER temperature data are utilized for studying the response of the lower thermosphere to the recurrent auroral heating. The COSMIC and SABER measurements are analyzed by one and the same method where the atmospheric tides and planetary waves which are present in the temperature and electron density measurements are simultaneously extracted from the data. The use of such data analysis approach brings to light additional features of the ionospheric response to a recurrent geomagnetic activity which have not been found before.

► A detailed response assessment is possible only by its proper extraction from the data. ► Different relations between foF2 and hmF2 over equator and at latitudes of ±50° are seen. ► Winter anomaly defines a stronger response in winter than that in summer.