Unveiling the Gannon Storm: How Ground-Based Magnetometers Mapped Its Global Impact

Abstract

The Gannon Storm, also known as the Mother's Day Storm of May 2024, ranks among the most intense geomagnetic disturbances of the space age, triggered by a powerful interplanetary coronal mass ejection. Leveraging data from over 100 globally distributed magnetic observatories, this study provides a detailed analysis of its ground-level impacts, focusing on the horizontal and vertical components of the magnetic field and the rate of change of horizontal intensity (Formula presented.). Global and polar maps reveal the equatorward expansion of auroral electrojets, asymmetric ring current dynamics, and significant regional variations in geomagnetic responses. Rapid (Formula presented.) variations, a key proxy for geomagnetically induced currents, pinpoint regions potentially at risk. This study provides a detailed characterization of the ground-level impacts of this superstorm.