Document Type

Article

Publication Date

1-26-2022

Abstract

Sporadic-E (Es) occurrence rates from Global Position Satellite radio occultation (GPS-RO) measurements have shown to vary by a factor of five between studies, motivating the need for a comparison with ground-based measurements. In an attempt to find accurate GPS-RO techniques for detecting Es formation, occurrence rates derived using five previously developed GPS-RO techniques are compared to ionosonde measurements over an eight-year period from 2010–2017. GPS-RO measurements within 170 km of a ionosonde site are used to calculate Es occurrence rates and compared to the ground-truth ionosonde measurements. The techniques are compared individually for each ionosonde site and then combined to determine the most accurate GPS-RO technique for two thresholds on sporadic-E intensity: no lower limit and fbEs ≥3 MHz. Overall, the YuS4 method shows the closest agreement with ionosonde measurements for total Es occurrence rates without a lower limit on intensity, while the phase-based Chu technique shows the closest agreement for fbEs ≥3 MHz. This analysis demonstrates that the variation in GPS-RO derived sporadic-E occurrence rates is due to varying thresholds on the sporadic-E intensities in terms of fbEs.

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Copyright statement: © 2022 by the Authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY 4.0) license (https:// creativecommons.org/licenses/by/ 4.0/).

Associated data objects: GNSS and Digisonde sporadic-E maps produced by Air Force Institute of Technology. https://zenodo.org/records/6977022 (Version 1 available under Additional Files below.)

Funding note: This research was funded by the Air Force Office of Scientific Research (AFOSR/RTB1).

DOI

10.3390/rs14030581

Source Publication

Remote Sensing

GPSRO_crossings_0-3UTC_Jul_13_S4.pdf (32 kB)
GNSS and Digisonde sporadic-E maps produced by Air Force Institute of Technology

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