Combined model of topside ionosphere and plasmasphere derived from radio-occultation and Van Allen Probes data

Abstract

In the last years, electron density profile functions characterized by a linear dependence on the scale height showed good results when approximating the topside ionosphere. The performance above 800 km, however, is not yet well investigated. This study investigates the capability of the semi-Epstein functions to represent electron density profiles from the peak height up to 20,000 km. Electron density observations recorded by the Van Allen Probes were used to resolve the scale height dependence in the plasmasphere. It was found that the linear dependence of the scale height in the topside ionosphere cannot be directly used to extrapolate profiles above 800 km. We find that the dependence of scale heights on altitude is quadratic in the plasmasphere. A statistical model of the scale heights is therefore proposed. After combining the topside ionosphere and plasmasphere by a unified model, we have obtained good estimations not only in the profile shapes, but also in the Total Electron Content magnitude and distributions when compared to actual measurements from 2013, 2014, 2016 and 2017. Our investigation shows that Van Allen Probes can be merged to radio-occultation data to properly represent the upper ionosphere and plasmasphere by means of a semi-Epstein function.

A novel neural network model of Earth’s topside ionosphere

“…Furthermore, it is possible to connect the model presented here to the plasmaspheric altitudes. Recently, Prol et al 33 demonstrated that the scale height in the plasmasphere exhibits a quadratic dependence on altitude, and found a functional dependence which allowed to connect the radio occultation profiles with in situ observations of electron density in the plasmasphere made by the Van Allen Probes mission. Using the methodology of Prol et al 33 , it is possible to connect the model presented in this study to the plasmasphere, making it a full topside option valid up to the GNSS altitudes and beyond.…”

“…Recently, Prol et al 33 demonstrated that the scale height in the plasmasphere exhibits a quadratic dependence on altitude, and found a functional dependence which allowed to connect the radio occultation profiles with in situ observations of electron density in the plasmasphere made by the Van Allen Probes mission. Using the methodology of Prol et al 33 , it is possible to connect the model presented in this study to the plasmasphere, making it a full topside option valid up to the GNSS altitudes and beyond. Therefore, the model developed in this study combined with its plasmaspheric extension can be incorporated into the IRI as a novel option for specifying the topside ionosphere and plasmasphere.…”

Simulations of Dedicated LEO-PNT Systems for Precise Point Positioning: Methodology, Parameter Analysis, and Accuracy Evaluation

“…They can be efficiently used to represent the ionospheric delay in the signal path between the classic GNSS satellites and the ground. However, in LEO-PNT, a large region above the LEO orbit height (up to 20,000 km), corresponding to the topside ionosphere and plasmasphere [82], [83], [84], should be removed from the current ionospheric models. In this regard, three-dimensional (3D) models are more realistic for LEO-PNT systems.…”

Rádio Ocultação GNSS: Revisão Teórica, Missões e Produtos

“…Existe uma vasta gama de investigações que ainda se faz necessária nessa área de pesquisa, não apenas em relação às novas missões, mas também quanto às configurações de processamento, metodologias envolvidas na obtenção e validação dos perfis atmosféricos e, ainda, as metodologias de assimilação dos dados de RO-GNSS em modelos atmosféricos. Diversos estudos recentes apresentam importantes contribuições em relação à atmosfera neutra (ANTHES et al, 2022;FU et al, 2022;YANG, 2022) e à ionosfera (BERGSSON;SYNDERGAARD, 2022;SUN et al, 2022;PROL et al, 2022).…”