Time causal operational estimation of electric fields induced in the Earth's lithosphere during magnetic storms

Geophysical Research Letters
By:  and 

Links

Abstract

In support of projects for monitoring geomagnetic hazards for electric power grids, we develop a simple mathematical formalism, consistent with the time causality of deterministic physics, for estimating electric fields that are induced in the Earth's lithosphere during magnetic storms. For an idealized model of the lithosphere, an infinite half‐space having uniform electrical conductivity properties described by a galvanic tensor, we work in the Laplace‐transformed frequency domain to obtain a transfer function which, when convolved with measured magnetic field time series, gives an estimated electric field time series. Using data collected at the Kakioka, Japan observatory, we optimize lithospheric conductivity parameters by minimizing the discrepancy between model‐estimated electric field variation and that actually measured. With our simple model, we can estimate 87% of the variance in storm time Kakioka electric field data; a more complicated model of lithospheric conductivity would be required to estimate the remaining 13% of the variance. We discuss how our estimation formalism might be implemented for geographically coordinated real‐time monitoring of geoelectric fields.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Time causal operational estimation of electric fields induced in the Earth's lithosphere during magnetic storms
Series title Geophysical Research Letters
DOI 10.1002/2014GL059568
Volume 41
Issue 7
Year Published 2014
Language English
Publisher AGU
Contributing office(s) Geologic Hazards Science Center
Description 9 p.
First page 2266
Last page 2274