Global‐Scale Ionospheric Tomography During the March 17, 2015 Geomagnetic Storm

Abstract

Measuring the electron density in the ionosphere is an important step to improve our understanding of the solar-terrestrial environment impact on communication, surveillance, and navigation systems. Several methods can be applied to estimate the three-dimensional (3D) electron density in the ionosphere (Bust & Mitchell, 2008). In this context, the computerized ionospheric tomography (CIT) gained attention in the last three decades since it provides accurate observations of the ionospheric electron density over large areas (Austen et al., 1988;Norberg et al., 2018). The main products are 3D spatial fields of the electron density, which evolve with time in a series of snapshots. Over the last 20 years, several achievements have been obtained by CIT techniques. It has been demonstrated that these images can be used to describe the overall ionospheric plasma structure and its temporal evolution in the atmosphere. They have been successfully used to represent important ionospheric dynamics, such as traveling ionospheric disturbances (Bolmgren et al., 2020;Chen et al., 2016), geomagnetic storm signatures

A‐CHAIM: Near‐Real‐Time Data Assimilation of the High Latitude Ionosphere With a Particle Filter

“…There are many data assimilation techniques used in ionospheric research, and by the broader geophysical community, each with their own advantages and disadvantages (Angling et al., 2009; Bust & Immel, 2020; Chartier et al., 2016; Elvidge, Sean & Angling, Matthew J., 2019; Lee et al., 2012; Nickisch et al., 2016; Prol et al., 2021; Scherliess et al., 2004; Schunk et al., 2016; Spencer & Mitchell, 2003). Any choice of assimilation technique for A‐CHAIM must be able to operate in near‐real‐time on reasonable hardware.…”

“…There exist a dozen or more different data assimilation models of the ionosphere that mainly use GNSS slant TEC measurements. Unfortunately, the path‐integrated nature of these measurements heavily restricts the constraint afforded by them, particularly in the vertical distribution of electron density, and instrumental biases pose a substantial challenge, particularly at high latitudes (Coster et al., 2013; Nesterov & Kunitsyn, 2011; Prol et al., 2021; Themens et al., 2015).…”

“…The reconstruction of a 2D or 3D density using line integrals (tomography) is a common nonlinear inverse problem across many fields in medicine and geophysics. Tomographic techniques with radiofrequency beacon satellites for ionospheric studies have been practiced for decades (Prol et al., 2021). However, tomography works best when you have dense, evenly spaced networks of receivers (Chartier et al., 2014), which are not available in the high latitude region.…”

The Mechanism for GNSS‐Based Kinematic Positioning Degradation at High‐Latitudes Under the March 2015 Great Storm

“…The St. Patrick's storm on 17 March 2015 was the strongest during the 24 solar cycle. A considerable number of researchers have investigated the ionospheric disturbances as well as the GPS positioning performance associated with the great storm (Cherniak & Zakharenkova, 2015; Cherniak et al., 2015; Jacobsen & Andalsvik, 2016; Jin et al., 2017, 2019; Liu et al., 2016; Mansilla, 2019; Nava et al., 2016; Poniatowski & Nykiel, 2020; Prikryl et al., 2016; Prol et al., 2021; Yao et al., 2016; Zakharenkova et al., 2016, 2019). Particularly, Yang et al.…”

“…The St. Patrick's storm on 17 March 2015 was the strongest during the 24 solar cycle. A considerable number of researchers have investigated the ionospheric disturbances as well as the GPS positioning performance associated with the great storm Jacobsen & Andalsvik, 2016;Jin et al, 2017Jin et al, , 2019Liu et al, 2016;Mansilla, 2019;Nava et al, 2016;Poniatowski & Nykiel, 2020;Prikryl et al, 2016;Prol et al, 2021;Yao et al, 2016;Zakharenkova et al, 2016Zakharenkova et al, , 2019. Particularly, Yang et al (2020) conducted a comprehensive accuracy assessment of the kinematic PPP using more than 5,000 stations around the world, focusing on the relationship between the positioning degradation and the ionospheric plasma irregularities NIE ET AL.…”