Ionospheric and plasmaspheric electron contents from space-time collocated digisonde, COSMIC, and GPS observations and model assessments

Abstract

An accurate representation of bottomside, topside ionosphere, and plasmasphere electron content remains as one of the important issues for the development of realistic ionosphere and plasmasphere models. The reason is that the full altitude electron density profile specification is restricted by a simultaneous lack of adequate ground or space-based datasets. In this article, we present sensible assimilation of peak parameters in the topside profiles from the FormoSat-3/COSMIC ionospheric occultations with the auto-scaled bottomside profiles from 39 global Digisonde rather than peak to topside extrapolation. Under strict space-time collocation criteria, the integral electron content from the assimilated electron density profiles along with global positioning system derived total electron content demonstrates altitude dependent contributions. The corresponding estimations from the empirical ionospheric and plasmaspheric models (IRI-2016, NeQuick-2, and IRI-Plas 2017) are also assessed to realize their discrepancies with respect to the observed parameters. The statistical comparison metrics show relatively closer overall ionospheric electron content estimates from IRI with the assimilated results, followed by NeQuick and IRI-Plas models, with the last two models showing an opposite behavior between bottomside and topside electron content discrepancies. However, although the total electron content estimations reveal the relatively superior performance of IRI-Plas with successive proficiency of NeQuick and IRI models, the retrieved plasmaspheric electron content data does not evident any clear statistical metrics and dictates further investigation. Nevertheless, this assimilation work leads towards improving the altitudinal representation of ionospheric models, particularly in the context of real-time representation of topside, bottomside, and plasmaspheric electron content through a reconstruction of the complete electron density profile.