O bserved Electric Field Changes o f Positive Lightning Flashes Preceded b y Preliminary Breakdown i n Padang

Abstract

Positive lightning can do more damage than negative lightning. We have observed 77 positive cloud to ground (CG) flashes preceded by preliminary breakdown (PB) in Padang, Indonesia. It was found that there were two types of polarity between the PB pulse train and the following first return stroke (RS) pulses, namely the same polarity (type S) and composite polarity (type C). The occurence percentages of type S and type C were 92.2% and 7.8%, respectively. The aritmathic mean (AM) and geometric mean (GM) PB/RS separations and durations were 97.31 ms, 76.33 ms and 98.15 ms, 77.49 ms, respectively. The AM and GM PB/RS ratios were 12.26% and 10.20%, respectively. In addition, the characteristics of the PB pulse such as individual pulse duration, pulse train duration, and interpulse duration are discussed in this paper.

Unravel the extent of the existence of positive ground flash in Malaysia

“…[12] discovered a numerous +CG data from a single storm with 102 event which is extraordinary abundance from a single storm. Next, [13] and [14] discovered a relatively low percentage of +CG lightning in Indonesia with only 0.68%. In this study, 4.44% positive lightning are detected from overall electric field data thus aligned with initial literature which stated that the occurrence of positive ground flashes is only about 10% compared to negative ground flashes.…”

“…The characteristics of positive flashes in the tropics of Indonesia were presented by [13] and [14] in 2017. The data analyzed in this study were recorded on 31 thunderstorms from May to October 2014 by using a circular flat-plate parallel antenna that was connected to buffer electronics and digitized with a 12-bit digitizing oscilloscope.…”

Reconstruction of Lightning Channel Based on Acoustic Radiation

“…When the stepped leader approaches the ground (downward leader), its negative charge attracts concentrated positive charge on the ground (upward leader) [6][7][8][9]. Furthermore, one of these upward leaders will attach with a branch of the downward leader, causing a return stroke.…”