The first comparison between Swarm-C accelerometer-derived thermospheric densities and physical and empirical model estimates

The first systematic comparison between Swarm-C accelerometer-derived thermosphericdensity and both empirical and physics-based model results using multiple model performance metricsis presented. This comparison is performed at the satellite’s high temporal 10-s resolution, which providesa meaningful evaluation of the models’ fidelity for orbit prediction and other space weather forecastingapplications. The comparison against the physical model is influenced by the specification of the loweratmospheric forcing, the high-latitude ionospheric plasma convection, and solar activity. Some insightsinto the model response to thermosphere-driving mechanisms are obtained through a machine learningexercise. The results of this analysis show that the short-timescale variations observed by Swarm-C duringperiods of high solar and geomagnetic activity were better captured by the physics-based model thanthe empirical models. It is concluded that Swarm-C data agree well with the climatologies inherent withinthe models and are, therefore, a useful data set for further model validation and scientific researc