Effects of geomagnetic storms on the accuracy of orbit-derived atmospheric density measurements

Abstract

We elucidated the effects of geomagnetic storms on the accuracy of orbit-derived densities. Two different methods were used to estimate densities along the Challenging Minisatellite Payload (CHAMP) satellite trajectory with two types of orbital data: low-accuracy high-spatial coverage mean orbital element (MOE) data, and high-precision low-quantity precise orbit ephemeris (POE) data. 12 cases under different geomagnetic conditions were selected. The biases in orbit-derived and empirical model densities with respect to three different sources of accelerometer-based density data sets were calculated. The main purpose of this research is to give a quantified analysis to the impact of different geomagnetic storm events on the precision of orbit-derived densities. Meanwhile, the influence of different integral time spans adopted in the density deriving procedures were also investigated and discussed, which might be helpful for other research teams on the selection of the optimal integral time spans. Results show that the POE data could induce higher precision and higher temporal resolution atmospheric density under all geomagnetic conditions, given that the Sutton densities are assumed as the baseline data.