Variation of Total Electron Content over May 10 - 13 2024 Geomagnetic Super Storm in South Africa

This study investigates the variation of Total Electron Content (TEC) over South Africa during the geomagnetic superstorm of May 10 - 13, 2024. This study aims to analyze the variation of TEC over South Africa during the May 10 - 13, 2024, geomagnetic superstorm using data from the IRI-2020 model, GNSS-based TEC measurements, and other geomagnetic parameters. The root mean square error (RMSE) method was applied to quantify the deviations between GPS-derived TEC measurements and the IRI-2020 model during the geomagnetic storm. The results reveal significant TEC fluctuations, with a pronounced increase during the main phase due to prompt penetration electric fields (PPEFs) and storm-induced ionospheric disturbances. This was followed by a sharp TEC depletion in the recovery phase, attributed to thermospheric composition changes, particularly oxygen-to-nitrogen ratio variations. Magnetometer H-component observations further confirm the strong geomagnetic activity associated with the storm, indicating enhanced ionospheric currents and electrodynamic coupling. Latitudinal variations in TEC revealed complex ionospheric dynamics, with more pronounced disturbances at mid-latitudes. The ionospheric irregularities affected GNSS-based positioning, highlighting the impact of geomagnetic storms on navigation systems. These findings provide valuable insights into ionospheric storm effects over South Africa, contributing to improved space weather forecasting, GNSS accuracy, and regional ionospheric modeling.