Imputation of geomagnetic disturbance fields with non-linear regression
based on synthetic data
Abstract
Geomagnetic disturbance, or perturbations in ground-level magnetic field
vectors relative to the quasi-static terrestrial main field, induces
geoelectric fields at and below Earth’s surface. This leads to
geomagnetically induced currents in high-voltage electric power systems
that can interfere with their operations. The sparse geospatial
distribution of reliable real time ground magnetometers is not presently
adequate for accurate geoelectric field estimation using traditional
interpolation techniques, or even more sophisticated inverse models (for
example, a spherical elementary current system) alone. To address this
shortcoming, we first generate multivariate statistics on a regular grid
using state-of-the-art global magneto-hydrodynamics (MHD) simulations.
These synthetic data strongly resemble real observations in a
statistical sense, although they do not generally reproduce the detailed
time evolution of observations due to poorly known MHD boundary
conditions. However, these statistics can and are used to regress on
sparse observations in order to fill in, or “impute”, the unobserved
points on a regular grid over North America.