The Potential of Remote Sensing for Neutral Atmospheric Density Estimation in a Data Assimilation System

New data assimilation techniques have improved time-dependent estimates of the neutral atmospheric density, making it possible to better estimate the drag perturbation on low-Earth-orbiting satellites. This study looks at the potential for using satellite remote sensing from space as an effective density observation source in a data assimilation system. Changes in the neutral density can occur on a minute-to-minute basis, particularly during geomagnetic storms. Although coverage from only a few (two) satellites may be limited, remote sensing provides observations with a high temporal and spatial resolution. To quantify the effectiveness of the observing platform, a simulated “truth” neutral atmosphere is created using a physical model. This “truth” neutral atmosphere is sampled according to the mechanics of the remote sensing platform, and the results are statistically evaluated. With the resolution afforded by remote sensing, results show that two remote sensing satellites provide a stable solution of degree 4 (5 × 5) every ten minutes. Although coverage from two remote sensing satellites is limited, the coverage is sufficient to provide a pattern correlation coefficient consistently higher than 0.92.