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One-Dimensional Variational Ionospheric Retrieval Using Radio Occultation Bending Angles: Part 2 - Validation
  • Sean Elvidge,
  • Sean B. Healy,
  • Ian Culverwell
Sean Elvidge
University of Birmingham

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Sean B. Healy
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Ian Culverwell
Met Office
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Culverwell et al. (2023) described a new one-dimensional variational (1D-Var) retrieval approach for ionospheric GNSS radio occultation (GNSS-RO) measurements. The approach maps a one-dimensional ionospheric electron density profile, modeled with multiple ”Vary-Chap’ layers, to bending angle space. This paper improves the computational performance of the the 1D-Var retrieval using an improved background model and validates the approach by comparing with the COSMIC-2 profile retrievals, based on an Abel Transform inversion, and co-located (within 200 km) ionosonde observations using all suitable data from 2020. A three or four layer Vary-Chap in the 1D-Var retrieval shows improved performance compared to COSMIC-2 retrievals in terms of percentage error for the F2 peak parameters (NmF2 and hmF2). Furthermore, skill in retrieval (compared to COSMIC-2 profiles) throughout the bottomside (~90 km to 300 km) has been demonstrated. With a single Vary-Chap layer the performance is similar, but this improves by approximately 40% when using four-layers.
02 Jun 2023Submitted to ESS Open Archive
07 Jun 2023Published in ESS Open Archive