Ionospheric electron content during solar cycle 23

Thermospheric density during 2008-2009, at the benchmark 400-km altitude, was shown to be approximately 30% lower than the previous solar minimum during 1996, in observations and in model simulations. Ionospheric densities were also estimated to be lower, by 10% to 20%.

However, earlier analyses using data from the global network of Global Navigation Satellite System receivers did not find any significant reduction in global mean total electron content. Recent work reexamining those data using a limited set of receivers, but with consistent processing, identified a 19% reduction (Emmert et al., 2017, doi.org/10.1002/2016JA023680). In this study, we compare model simulations of the thermosphere-ionosphere system during the 2008-2009 solar minimum to its predecessor and estimate a 16% reduction in global mean total electron content.