# Effects of the October 2024 Storm over the Global Ionosphere
## 4 Results
### Spatio-Temporal Variations in the Ionospheric Characteristics
Their analysis revealed significant discrepancies in F-region uplift patterns due to the influence of PPEFs. At Jicamarca, an under-shielding electric field event around the time of the post-sunset PRE led to a maximum F-region uplift of nearly 700 km. In contrast, Sao Luis recorded a storm-induced uplift of ~560 km occurring approximately three hours earlier than the usual PRE timing. Additionally, they observed a second uplift event driven by DDEFs, with F-region heights reaching ~410 km over Sao Luis around 07:00 UT and ~450 km over Jicamarca at 08:00 UT on 11 October. This second uplift coincided with intensifying auroral oscillations, highlighting a complex and possibly coupled electrodynamic response between high-latitude auroral processes and equatorial ionospheric dynamics. To assess the impact of the geomagnetic storm on thermospheric composition, we compared the latitudinal and longitudinal distribution of the [O/N\({}_{2}\)] ratio under both quiet and disturbed conditions using data from the GUVI. This comparison is illustrated in Figure 9a-d. Under quiet conditions, as shown in Figure 9a, the [O/N\({}_{2}\)] ratio appears relatively uniform across all latitudes throughout the day. This consistency indicates efficient meridional and zonal transport of neutral particles, leading to a balanced composition and enhanced daytime recombination, with minimal spatial variability or lags in the neutral response. However, during disturbed conditions on 10-11 October, the global [O/N\({}_{2}\)] distribution, presented in Figure 9b,c, reveals significant deviations from the quiet-time pattern. Notably, large fluctuations in the [O/N\({}_{2}\)] ratio were observed over the equatorial and polar regions, indicating strong thermospheric disturbance. These fluctuations are likely the result of enhanced vertical and horizontal neutral wind circulation driven by geomagnetic forcing, which redistributes atomic oxygen and molecular nitrogen unevenly across latitudes. In contrast, the midlatitude region displayed relatively subdued [O/N\({}_{2}\)] variability, suggesting that longitudinal inhomogeneities in thermospheric composition were less pronounced in these regions during the storm. This indicates a more stable thermospheric activity, which is consistent with the observed vertical and horizontal neutral wind circulation driven by geomagnetic forcing. Figure 8: (**a–c**) Drift velocity components: (**a**) vertical drift, (**b**) north–south component of horizontal drift, and (**c**) east–west component of horizontal drift over three stations from 10 October to 12 October. The orange vertical lines represent the SSC, the grey vertical line denotes the time of the SYM-H index minimum during the storm, the pink line represents when SYM–H \(<-100\) nT during the recovery period, and the brown vertical line represents the end of the recovery phase of the ionosphere. mospheric response at midlatitude compared to the more dynamically perturbed equatorial and polar sectors, which are more directly influenced by storm-driven energy inputs and magnetosphere--ionosphere--thermosphere coupling process.