New density estimates derived using accelerometers on board the CHAMP and GRACE satellites

Atmospheric mass density estimates derived from accelerometers onboard satellites such as CHAllenging Minisatellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE) are crucial in gaining insight into open science questions about the dynamic coupling between space weather events and the upper atmosphere. Recent advances in physics‐based satellite drag coefficient modeling allow derivation of new density data sets. This paper uses physics‐based satellite drag coefficient models for CHAMP and GRACE to derive new estimates for the neutral atmospheric density. Results show an average difference of 14–18% for CHAMP and 10–24% for GRACE between the new and existing data sets depending on the space weather conditions (i.e., solar and geomagnetic activity levels). The newly derived densities are also compared with existing models, and results are presented. These densities are expected to be useful to the wider scientific community for validating the development of physics‐based models and helping to answer open scientific questions regarding our understanding of upper atmosphere dynamics such as the sensitivity of temporal and global density variations to solar and geomagnetic forcing. Key Points New CHAMP and GRACE accelerometer‐derived density estimates differ by up to 25% compared to previous estimates New gas‐surface interaction models and better modeling of satellite geometry improve drag coefficient estimates The original density estimates have the smallest difference of ∼12% for high solar activity increasing to ∼31% for low solar activity