Specification of the Ionosphere-Thermosphere Using the Ensemble Kalman Filter

Abstract

The Ionosphere-Thermosphere environment undergoes constant and sometimes dramatic changes due to solar and geomagnetic activity. Furthermore, given that this environment has a significant effect on space infrastructure, such as satellites, it is important to understand the potential changes caused by space weather events. This work presents the implementation of the ensemble Kalman filter assimilation technique to improve the nowcast and forecast of the thermosphere environment. Specifically, the assimilation tries to adjust F10.7, a solar radio flux parameter at 10.7 cm wavelength that acts as a proxy for solar activity. The results show that during high solar activity, the measured F10.7 index is able to account for the variability in the ionosphere-thermosphere, hence the correction provided by the assimilation is small. On the other hand, during low solar activity, F10.7 is unable to account for variability in the ionosphere-thermosphere, and the correction provided by the assimilation drastically improves the nowcast/forecast.