Analysis of variations of thermospheric density using different solar flux proxies and geomagnetic proxies

A satellite passing through the thermosphere will experience variations in its drag acceleration due to density variations. Orbital determination and prediction of these satellites requires accurate modeling of thermospheric density variations. The response of upper atmosphere to variations in solar and geomagnetic activity has been the focus of a number of studies in an effort to develop accurate atmospheric models and orbit prediction techniques. In this paper thermosphere density derived from the CHAMP satellite are analyzed using five solar flux proxies (F10.7, E10.7, Mg10.7, S10.7, Y10.7) and two geomagnetic proxies (ap, Dst). The results show: (a) Variations of density are consistent with that of five solar proxies and relative coefficient are all more than 0.97. (b) Variations of density have good relationship with two geomagnetic proxies. Especially Dst has better consistency with density on beginning time and increased amplitude. Finally, on the basis of relationship between density and Dst, a simple formulation to predict mean density is founded only using Dst index and is proved to be viable through comparison with CHAMP and GRACE-A .