10.1029/2025JA034932">
 

Height‐Dependent Evolution of the Ionospheric Response to the May 2024 Superstorm: Global GNSS‐POD, GNSS‐RO, and Ground‐Based Observations

Document Type

Article

Publication Date

5-28-2026

Abstract

Capturing global ionospheric response during extreme geomagnetic storms remains a major observational challenge. During 10–11 May, 2024 superstorm, we investigate the height‐dependent response of the F‐region using multi‐constellation GNSS‐POD limb‐sounding measurements from COSMIC‐2, Spire, PlanetiQ, and FengYun‐3 satellites. Approximately 12,000 vertical electron density (Ne) profiles per day are retrieved using an optimal‐estimation inversion, resolving both topside and bottomside structures. In parallel, we derive global vertical total electron content (vTEC) from 18,000 GNSS‐RO links per day, providing uniform sampling across land and ocean. During the storm's main phase, Ne profiles reveal dramatic F2‐layer uplifts exceeding 450 km, with localized peaks above 500 km and concurrent reductions in Ne near 300 km, consistent with storm‐time drifts. The equatorial ionization anomaly (EIA) expanded poleward, developed into a pronounced super‐fountain structure, and migrated westward with local time. This evolution, along with the merging of EIA crests with the expanding auroral oval, highlights strong coupling between low‐ and high‐latitude regions. As the storm entered the recovery phase, Ne between 250 and 450 km showed 55%–70% daytime depletions. At 350 km, Ne losses were up to three times larger in the summer hemisphere compared to the winter hemisphere, whereas at 250 km the winter hemisphere exhibited nearly double the depletion, indicating a reversal of interhemispheric asymmetry. Recovery was strongly altitude‐ and diurnal‐dependent, faster at low altitudes during daytime but slower at night in the northern hemisphere. We also incorporated ground‐based TEC measurements to track storm‐time high‐latitude irregularities and auroral boundary motion. We identify equatorward boundary migration to 33N, providing an effective tracer of auroral morphology during both day and night, complementing space‐based Ne signatures. Results demonstrate that the integration of multi‐satellite and ground‐based observations provides benchmarks for ionosphere‐thermosphere and space‐weather monitoring, modeling, and forecasting. , Plain Language Summary The geomagnetic superstorm of 10–11 May, 2024 was one of the strongest space‐weather events of Solar Cycle 25 and caused major disturbances in the ionosphere, affecting radio communication, GPS accuracy, and satellite drag. Understanding ionosphere changes during extreme storms is difficult because measurements are usually limited in coverage. In this study, we combine observations from several low‐Earth‐orbit satellites and ground‐based GNSS‐receivers to create the most complete global picture of how the ionosphere responded during this storm. Using 12,000 electron density profiles per day from GNSS satellite limb‐sounding and 18,000 vertical TEC measurements from GNSS radio occultation, we tracked how the ionosphere changed between 250 and 500 km. During the storm's main phase, the equatorial ionization anomaly expanded dramatically, and the F‐region plasma was lifted to unusually high altitudes. The recovery phase showed strong differences between hemispheres and between day and night. The recovery was strongly altitude‐ and diurnal‐dependent, faster at low altitudes during daytime but sluggish at night in the north. We also used ground‐based ROTI measurements to detect irregularities and to track the motion of the auroral boundary in the low latitudes, down to 33N. This study demonstrates improved capabilities to observe global ionospheric restructuring during extreme space‐weather events. , Key Points Multi‐constellation GNSS‐POD and GNSS‐RO Ne data reveal global, height‐dependent ionospheric responses, including EIA uplift and westward drift GNSS‐POD and ROTI are combined to investigate day‐night irregularities, expansion of auroral boundary, and its merging with EIA The recovery phase shows strong altitude‐, hemisphere‐, and diurnal‐dependent Ne depletion and subsequent recovery across both hemispheres

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© 2026 The Authors. Published by Wiley on behalf of the American Geophysical Union. 

This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives License, which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way. CC BY-NC-ND 4.0 

Funding note: National Aeronautics and Space Administration. Grant Numbers: 936723.02.01.12.48, 880292.04.02.01.68, 80NSSC24K1114

Issue date: June 2026

Source Publication

Journal of Geophysical Research: Space Physics (ISSN 2169-9380 | eISSN 2169-9402)

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