Empirical orthogonal function analysis and modeling of the ionospheric peak height during the years 2002-2011

In this paper, a global hm model based on the empirical orthogonal function (EOF) analysis method is constructed by using Global Navigation Satellite Systems ionospheric radio occultation measurements from COSMIC and CHAMP as well as global ionosonde data during the years 2002–2011.

The variability of hm can be well represented by the several EOF base functions Ek and the corresponding coefficients Pk. The rapid convergence of EOF decomposition makes it possible to use only the first four EOFs components, which express 99.133% of total variance in this study, to construct the empirical model. The variations of hm with respect to the magnetic latitude, local time, season, and solar cycle have been studied, and the EOF-based hm model has been validated through comparisons with the International Reference Ionosphere (IRI) model and other observation.