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An empirical model of the occurrence rate of low latitude post-sunset plasma irregularities derived from CHAMP and Swarm magnetic observations
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  • Claudia Stolle,
  • Tarique Adnan Siddiqui,
  • Lucas Fabian Schreiter,
  • Suman K. Das,
  • Ina Rusch,
  • Martin Rother,
  • Eelco Doornbos
Claudia Stolle
Leibniz Institut of Atmospheric Physics at the University of Rostock

Corresponding Author:[email protected]

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Tarique Adnan Siddiqui
Leibniz Institute of Atmospheric Physics
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Lucas Fabian Schreiter
GFZ German Research Centre for Geosciences
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Suman K. Das
Leibniz Institut of Atmospheric Physics at the University of Rostock
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Ina Rusch
Leibniz Institut of Atmospheric Physics at the University of Rostock
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Martin Rother
Deutsches GeoForschungsZentrum, GFZ
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Eelco Doornbos
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The prediction of post-sunset equatorial plasma depletions (EPDs), often called ionospheric plasma bubbles, has remained a challenge for decades. In this study, we introduce the Ionospheric Bubble Probability (IBP), an empirical model predicting the occurrence probability of EPDs derived from 9 years of CHAMP and 8.5 years of Swarm magnetic field measurements. The model predicts the occurrence probability of EPDs for a given longitude, day of year, local time and solar activity, for the altitude range 350-500 km, and low geographic latitudes of ± 45◦. IBP has been found to successfully reconstruct the distribution of EPDs as reported in previous studies from independent data. IBP has been further evaluated using one-year of partly untrained data of the Ionospheric Bubble Index (IBI). IBI is a Level 2 product of the Swarm satellite mission used for EPD identification. The relative operating characteristics (ROC) curve shows positive excursion above the no-skill line with Hanssen and Kuiper’s Discriminant (H&KSS) score of 0.66, 0.73, and 0.65 at threshold model outputs of 0.22, 0.18, and 0.18 for Swarm A, B, and C satellites, respectively. Additionally, the reliability plots show proximity to the diagonal line with a fairly decent Brier Skill Score (BSS) of 0.317, 0.320, and 0.316 for Swarm A, B, and C respectively. These tests indicate that the model performs significantly better than a no-skill forecast. The IBP model offers a compelling glimpse into the future of EPD forecasting, thus demonstrating its potential to reliably predict EPD occurrences. The IBP model is made publicly available.
29 Nov 2023Submitted to ESS Open Archive
01 Dec 2023Published in ESS Open Archive