Analysis of Magnetometer Data from a Strong G3 Geomagnetic Disturbance

Measuring the changes to the earth's magnetic field during geomagnetic disturbance (GMD) events provides valuable insights which can be used to better understand potential impacts of GMDs on the electrical power grid and develop mitigating measures. This paper analyzes variations in the magnetic field measurement data captured from 17 magnetometers placed across the United States over the course of a strong GMD event that occurred in early November 2021. Various correlation analyses are performed based on the magnetic field measurements and time-shifted signals during four distinct scenarios (pre-storm, early-storm, peak-storm, and post-storm). The results provide a better understanding of the changes in magnetic field patterns, which can lead to a more accurate assessment of the induced electric field on the grid.