# Effects of the October 2024 Storm over the Global Ionosphere
## 4 Results
### Spatio-Temporal Variations in the Ionospheric Characteristics
(2025) [5] documented G-conditions in European midlatitude ionograms during the 2024 Mother's Day superstorm, attributing this to abrupt extreme F-region uplift. Their subsequent global study further confirmed the widespread occurrence of G-conditions during that storm. To investigate the significant drop in hmF2--particularly over certain Southern Hemisphere nighttime sectors during the recovery phase--individual COSMIC--2 Ne profiles were examined. Figure 5a-h displays eight satellite passes between 00:00 and 03:00 UT, each confirming the presence of G-conditions, characterized by foF1 exceeding foF2 and the F1 layer misinterpreted as the Ne peak. This pattern was further validated by Figures 6a-h and 7a-h, covering the 03:00-06:00 UT and 09:00-12:00 UT intervals, respectively, which revealed similar G-condition signatures. The consistency of these observations across multiple satellite passes strongly supports the conclusion that G-conditions were widespread during the storm's main and early recovery phases. We also examined vertical and horizontal ion drift velocities using data from three Digisonde stations located in both Hemispheres. Figure 8a-c presents the variations in vertical (Vz), north--south (Vnorth), and east--west (Veast) ion drifts throughout the storm period. At Lualualaei, situated in the nightside equatorial sector of the Northern Hemisphere over the Pacific Ocean, a strong downward drift of approximately \(-153\) m/s was observed immediately following the SSC, indicating a pronounced negative storm effect in the nightside equatorial ionosphere. Although vertical drifts at this station showed considerable variability during the main phase, horizontal drift velocities remained relatively stable except during periods of heightened geomagnetic activity. Around 22:00 UT, a sharp southward drift of -480 m/s was recorded, followed by a high northward drift of \(\sim\)430 m/s at 23:00 UT. These alternating drifts suggest complex electrodynamic processes involving the equatorward expansion of the polar ionosphere and the poleward extension of equatorial plasma. Unfortunately, no drift data were available at Lualualaei during the storm recovery phase. Figure 5: **(a-h)** Electron density profiles of COSMIC—2 RO on 11 October from 00:00–03:00 UT over the region “A” marked in Figure 4a. At Eglin, located in the dayside equatorial sector of the Northern Hemisphere, an upward drift was recorded near the SYM-H minimum, which may signify the onset of G-conditions--when foF2 drops below foF1 due to plasma depletion and F-layer uplift. During the main and recovery phases, Eglin exhibited highly variable horizontal drift patterns, including northeastward drifts of ~700 m/s by 23:27 UT, a shift to northwestward drifts of over 500 m/s at 00:57 UT, and a further intensification to ~900 m/s by 01:42 UT, before settling into a predominantly westward flow. These rapid and large-amplitude changes in drift direction and magnitude reflect the dynamic response of the dayside ionosphere to storm-time electric field penetration and thermospheric wind modification. In the Southern Hemisphere, over Ascension Island, located in the equatorial sector, intense upward (~170 m/s) and southwestward (~1000 m/s) drifts were observed during the storm's main phase. These signatures are consistent with a poleward expansion of the EIA, likely driven by prompt penetration electric fields (PPEFs). During the storm's recovery phase, upward and southwestward drifts remained dominant, aligning with findings from [PERSON] et al. (2025) [18], who reported similar drift patterns at Ascension Island during this period. Figure 6: (**a**–**h**) Electron density profiles of COSMIC—2 RO on 11 October from 03:00–06:00 UT over the region “B” marked in Figure 4b. Figure 7: (**a**–**h**) Electron density profiles of COSMIC—2 RO on 11 October from 09:00–12:00 UT over the region “C” marked in Figure 4d. [PERSON] et al. (2025) [18] further examined equatorial ionospheric behaviour during the storm by comparing observations from Sao Luis and Jicamarca stations.