Surface electric fields for North America during historical geomagnetic storms

Space Weather
By: , and 



To better understand the impact of geomagnetic disturbances on the electric grid, we recreate surface electric fields from two historical geomagnetic storms—the 1989 “Quebec” storm and the 2003 “Halloween” storms. Using the Spherical Elementary Current Systems method, we interpolate sparsely distributed magnetometer data across North America. We find good agreement between the measured and interpolated data, with larger RMS deviations at higher latitudes corresponding to larger magnetic field variations. The interpolated magnetic field data are combined with surface impedances for 25 unique physiographic regions from the United States Geological Survey and literature to estimate the horizontal, orthogonal surface electric fields in 1 min time steps. The induced horizontal electric field strongly depends on the local surface impedance, resulting in surprisingly strong electric field amplitudes along the Atlantic and Gulf Coast. The relative peak electric field amplitude of each physiographic region, normalized to the value in the Interior Plains region, varies by a factor of 2 for different input magnetic field time series. The order of peak electric field amplitudes (largest to smallest), however, does not depend much on the input. These results suggest that regions at lower magnetic latitudes with high ground resistivities are also at risk from the effect of geomagnetically induced currents. The historical electric field time series are useful for estimating the flow of the induced currents through long transmission lines to study power flow and grid stability during geomagnetic disturbances.
Publication type Article
Publication Subtype Journal Article
Title Surface electric fields for North America during historical geomagnetic storms
Series title Space Weather
DOI 10.1002/swe.20073
Volume 11
Issue 8
Year Published 2013
Language English
Publisher Wiley
Contributing office(s) National Earthquake Information Center
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Space Weather
First page 451
Last page 462
Country United States
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