Time domain polarization analysis of Schumann resonance waveforms

Schumann resonance waveforms in the lower ELF band are produced by distant lightning
discharges. The multiplicity of world-wide thunderstorm centres provides a background spectrum which is
generally incoherent. Superimposed on this background are larger amplitude events from individual
thunderstorm centres. Source direction finding requires the determination of the polarization properties of
these complex and superimposed waveforms. A time domain polarization analysis technique is described
and applied to a variety of examples of Schumann resonance waveforms. The background waveforms
display the anticipated level of incoherent polarization properties. It is demonstrated that the technique can
isolate individual waveforms that are linearly polarized and which represent the arrival of short path signals
from single source locations.