Electric field change waveforms produced by the strongest negative lightning strokes in winter thunderstorms
Abstract
Strong electric field change pulses having the same polarity as those produced by negative return strokes and having estimated peak current larger than 150 kA (absolute value) are examined. It is found that these strongest negative pulses share some similarities with typical negative return stroke pulses but also have some clear differences. First, most pulses have comparable rise time and fall time, different from return stroke pulses which usually have much larger fall time than rise time. Second, discharges preceding these pulses have very short durations (<700 s), while discharges preceding first return strokes in negative CG flashes consist of preliminary breakdown and stepped leader processes, normally having durations of several to tens of ms. Based on a statistical analysis of waveform characteristics and a direct optical observation of the discharge producing a 335-kA pulse, We provide conclusive evidence that these pulses are produced by strong first strokes in negative CG flashes. In other words, strongest negative return strokes in winter produce E-change waveforms that are generally different from normal return strokes. We also demonstrate that these strongest negative return strokes are preceded by a fast downward negative leader with large peak currents.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFMAE25A1922W