SAIP2025

The impact of geomagnetic storms and solar proton events in May and October 2024 on South Africa’s upper atmosphere, compared to the historical event of October 2003

9 Jul 2025, 11:50

20m

Solomon Mahlangu House (University of the Witwatersrand, Johannesburg)

Oral Presentation Astrophysics & Space Science

Speaker

Joseph Omojola (North-West University)

Description

This study investigated the impact of solar proton events (SPE) on the upper atmosphere over
South Africa during intense geomagnetic storms in May (Dst = -412 nT) and October 2024 (Dst
= -333 nT). Utilizing the NRLMSISE-2.0 atmospheric model and SOHO data, we characterized
storm-time atmospheric composition and energetic particle fluxes. Significant fluctuations in atmospheric
constituents were observed, with molecular nitrogen (N₂) increasing by
3.61×10⁶ cm^-3 day^-1 during the May sudden storm commencement
(SSC) and by 1.40×10⁶ cm^-3 day^-1 and 2.26×10⁶
cm^-3 day^-1 during the two-step SSC of October. A decrease in atomic
hydrogen (H) of about 3.0×10⁴ cm^-3 day^-1 occurred in
May, while the largest decrease of approximately 8.60×10³ cm^-3 day^-
1 was noted during the October storm. These changes, driven by particle precipitation that
enhances nuclear and molecular interactions at GNSS altitudes (400 –450 km), affect the total electron
content (TEC) and may compromise GNSS signal accuracy. The results are compared with
the historical event of solar cycle 23 in October 2003 (Dst = -353nT). This research enhances our
understanding of space weather’s impact on the upper atmosphere and related technologies.