A Climatological Analysis of Geoelectric Field Variations

Abstract:

Geomagnetic variations induce currents that flow along natural and artificial conducting pathways including critical infrastructure such as the electrical power grid. The level of induction is controlled by the geoelectric field at the Earth's surface, which may be calculated by convolving the geomagnetic variations with an earth-conductivity model. We carry out a long-term statistical analysis of calculated geoelectric field variations using about 30 years of geomagnetic observations from selected locations. We find two dominant classes of geoelectric field events: those that are driven by shock arrival at the Earth which produces a sudden impulse or sudden storm commencement, and those that are associated with geomagnetic storm activity. We provide a historical perspective on the distribution of the geoelectric field for these types of events and compare the geoelectric field with other measures of geomagnetic activity. We also demonstrate the sensitivity of these results to different conductivity models and to geomagnetic latitude.