Using ground magnetometer arrays to reconstruct surface electric fields during historical geomagnetic storms

Author: and
Date: 
December 3, 2012
Type: 
Poster presentation
Venue: 
AGU Fall Meeting 2012
Citation: 

Lisa H. Wei; Nicole Homeier; Jennifer L. Gannon (2012) Using ground magnetometer arrays to reconstruct surface electric fields during historical geomagnetic storms. AGU Fall Meeting, San Francisco, CA. 

The approach of the next solar maximum will likely see an increase in solar activity and, indirectly, geomagnetic storms on Earth resulting from strong Coronal Mass Ejections from the Sun. To study the impact of these storms, we are developing a database of surface electric fields for the continental U.S. using the strongest geomagnetic storms on the Dst/Dxt scale from 1980-2009. This includes the March 1989 "Quebec event", which resulted in the collapse of the power grid the across the entire province. We discuss our analysis of the magnetic field data and the calculation of the surface electric fields during these historical storms. Using spherical elementary current systems, we interpolate the SUPERMAG compilation of magnetometer data across the continental U.S. during these events and find good agreement between the measured and interpolated magnetic fields. We combine the magnetic field data with the surface impedances from the United States Geological Survey for physiographic regions to create a database of horizontal, orthogonal surface electric field components (E_x and E_y) in one-minute timesteps for each of the storms. Comparison between electric fields derived from 10-second and one-minute magnetic field data show that they are relatively consistent, although the one-minute data appears to average out the most intense spikes in the surface electric field.