Characterization of Lightning Electric Field Waveforms Using a Large Database: 1. Methodology.

A new approach to the characterization of CG lightning electric field waveforms using a large database is presented. The waveforms, recorded in a wide (160 Hz–500 kHz) frequency range, are categorized into groups, depending on stroke order (first or subsequent), time of day (to distinguish between the daytime and nighttime ionosphere heights), and distance range. For each group, a representative waveform (including the ground wave and one-hop skywave) was found by averaging a large number of individual amplitude-normalized waveforms on a -100 to 500 μs time scale (t = 0 corresponds to the peak of the return-stroke ground wave). In this article, the methodology of waveform classification and averaging is presented and discussed. In the companion paper, the developed methodology is applied to analyzing variation of lightning electric field waveforms of different type with distance in the 10 to 500 km range. [ABSTRACT FROM AUTHOR]