Performance of the Ionospheric Kappa‐Correction of Radio Occultation Profiles Under Diverse Ionization and Solar Activity Conditions

Abstract

The kappa-correction of radio occultation profiles is explored for low and high ionization, solar activity, and asymmetry• The mean correction is most relevant under high ionization and symmetry, reach-10 ing near 0.05 µrad around 50 km 11 • Intercomparison with other datasets shows it predominantly decreases retrieved 12 stratospheric temperature errors

Understanding Ionospheric and Geomagnetic Effects on Residual Biases in Radio Occultation Data for Stratospheric Climate Monitoring

“…For enabling classification into nearly symmetric, moderately asymmetric, and strongly asymmetric cases we used the following formal definition of the f IA , in line with Liu et al (2020) and Danzer et al (2021).…”

Systematic Ionospheric Residual Errors in GNSS Radio Occultation: Theory for Spherically Stratified Media

“…(1996) studied the accuracy of the bending angle correction method and suggested the additional correction of systematic residual errors by numerical simulations given a priori knowledge of the ionospheric electron density. Over the past decade, an increased number of studies have assessed the systematic residual errors in bending angle either by simulation experiments using ray tracing (Coleman & Forte, 2017; Danzer et al., 2013, 2015; Li et al., 2020; Liu et al., 2013, 2015, 2018; Mannucci et al., 2011; Qu et al., 2015) or by theoretical considerations and empirical analyses using the relation between refractivity and bending angle under the assumption of local spherical symmetry (Angling et al., 2018; Danzer et al., 2020, 2021; Fan et al., 2017; Healy & Culverwell, 2015; Liu et al., 2020). On the latter account, Healy and Culverwell (2015) derived and suggested a simple addition to the standard correction using the already measured L1 and L2 bending angles, thereby reducing the sensitivity of residual ionospheric correction to a priori knowledge, as well as reducing algorithm complexity.…”

“…On the latter account, Healy and Culverwell (2015) derived and suggested a simple addition to the standard correction using the already measured L1 and L2 bending angles, thereby reducing the sensitivity of residual ionospheric correction to a priori knowledge, as well as reducing algorithm complexity. This addition is now commonly known as the kappa‐correction (Danzer et al., 2020, 2021).…”

“…Those include ionospheric correction in combination with statistical optimization of bending angles (Gobiet & Kirchengast, 2004; Gorbunov, 2002), optimal filtering or smoothing of the L1 and L2 bending angle difference (Hajj et al., 2002; Kuo et al., 2004; Schwarz et al., 2018; Sokolovskiy et al., 2009; Steiner et al., 1999), reduction of fluctuations in the corrected bending angle via comparative discrimination or back propagation (Sokolovskiy et al., 2014), and ionospheric correction in the troposphere via extrapolation when one of the two GNSS signals is unavailable due to tracking limitations (Rocken et al., 1997; Zeng et al., 2016). Nor do we address residual errors in derived refractivity or temperature using the Abel transform and hydrostatic integration (Danzer et al., 2020, 2021; Kursinski et al., 1997; Rieder & Kirchengast, 2001; Schwarz et al., 2017). The residual errors in these variables are linked to the error in bending angle, but the details depend on the particular approach of statistical optimization and upper altitude initialization, and is therefore more difficult to describe in a general sense.…”

“…SYNDERGAARD AND KIRCHENGAST 10.1029/2022EA002335 2 of 26 thereby reducing the sensitivity of residual ionospheric correction to a priori knowledge, as well as reducing algorithm complexity. This addition is now commonly known as the kappa-correction (Danzer et al, 2020(Danzer et al, , 2021.…”