Impact of Solar Forcing on Thermospheric Densities and Spacecraft Orbits from CHAMP and GRACE

Abstract

The thermosphere is the outer gaseous shell of a planet’s atmosphere that exchanges energy with the space plasma environment. The energy deposition of solar irradiation and magneto‐ spheric inputs into the upper atmosphere can change the thermospheric density significantly. From a practical standpoint, unanticipated changes in the density of the thermosphere cause satellites to deviate from their anticipated paths, or ephemerides. Many studies have been pursued to investigate the variations of thermospheric densities caused by solar forcing, which includes solar irradiation and magnetospheric energy deposition [1-12]. However, the quantitative examination of the impact of thermospheric density changes associated with solar forcing on satellite orbits is rare, given that the simultaneous measurements of thermospheric density and precise tracking data of satellite are sparse.