The First Comparison Between Swarm-C Accelerometer-Derived Thermospheric Densities and Physical and Empirical Model Estimates

TL;DR

This study compares Swarm-C accelerometer-derived thermospheric densities with empirical and physics-based models at high temporal resolution, revealing better model performance during high solar activity and validating Swarm-C data for scientific use.

Contribution

First systematic comparison of Swarm-C thermospheric densities with multiple models at 10-s resolution, providing insights into model performance and response to space weather.

Findings

Physics-based model better captures high-activity variations.

Swarm-C data aligns with model climatologies.

Models' fidelity varies with space weather conditions.

Abstract

The first systematic comparison between Swarm-C accelerometer-derived thermospheric density and both empirical and physics-based model results using multiple model performance metrics is presented. This comparison is performed at the satellite's high temporal 10-s resolution, which provides a meaningful evaluation of the models' fidelity for orbit prediction and other space weather forecasting applications. The comparison against the physical model is influenced by the specification of the lower atmospheric forcing, the high-latitude ionospheric plasma convection, and solar activity. Some insights into the model response to thermosphere-driving mechanisms are obtained through a machine learning exercise. The results of this analysis show that the short-timescale variations observed by Swarm-C during periods of high solar and geomagnetic activity were better captured by the physics-based model than the empirical models. It is concluded that Swarm-C data agree well with the climatologies inherent within the models and are, therefore, a useful data set for further model validation and scientific research.