Characteristics of lightning-generated electric fields measured in the Bogotá Savanna, Colombia

Abstract

In this paper, important features of electric fields produced by cloud-to-ground (CG) lightning flashes in the central region of Colombia are analyzed. This study is the first conducted in the country where more than 100 CG lightning flash signatures are analyzed. The measurements were conducted at Bogotá, Colombia between August-September 2016. A total of 138 electric field waveforms obtained from 7 thunderstorms events with an average duration of 2.7 hours were included. The distance of the electric field signatures with respect to the measuring system was in the range between 40 and 249 km. The statistical analysis showed that 38% of the recorded negative CG flashes were singlestrokes, which is a high percentage in comparison with other tropical and sub-tropical regions. The maximum multiplicity during the season was 9 strokes per flash and the average duration of the multiple-stroke flashes was 165 ms. In addition, although electric field signatures present a signal-to-noise ratio (SNR) with a medium level, the preliminary breakdown pulse train was identified in 22.8% of the recorded flashes. The minimum and maximum duration of preliminary breakdown for the examined negative flashes were 800 ns and 22 ms, respectively. KEYWORDS:Cloud-to-ground lightning, Electric field, Negative return stroke, Preliminary breakdown pulses. RESUMENEn este artículo se presentan y analizan características importantes de los campos eléctricos producidos por rayos (flashes) nube-tierra (CG) en la región central de Colombia. Este estudio es el primero llevado a cabo en el país donde se analizan más de 100 registros de rayos CG. Las mediciones se realizaron en Bogotá, Colombia entre agosto y septiembre de 2016. En total, se incluyeron 138 formas de onda de campo eléctrico obtenidas a partir de 7 tormentas eléctricas con una duración media de 2,7 horas. La distancia de los registros de campo eléctrico estuvo entre 40 y 249 km con respecto al sistema de medición. El análisis estadístico mostró que el 38% de los rayos CG negativos registrados presentaron una sola descarga de retorno (return stroke), lo cual es un porcentaje alto en comparación con otras regiones tropicales y subtropicales. La multiplicidad máxima registrada durante la temporada fue de 9 strokes por flash y la duración media de los flashes con múltiples strokes fue de 165 ms. Además, aunque las formas de onda del campo eléctrico presentan una relación señal-a-ruido (SNR) con un nivel medio, se identificó el tren de impulsos asociados a las descargas preliminares en el 22,8% de los flashes registrados. La duración mínima y máxima de la descarga preliminar para los flashes negativos examinados fue de 800 ns y 22 ms, respectivamente.

Lightning generated electric field over land and sea at Northern Region of Peninsular Malaysia: Measuring Setup

“…A number of researchers presented new findings on lightning event characteristics via electrical field sensors [15][16][17][18][19]. All lightning activities are correlated with charge movement and therefore, it can be studied using measurement of electrostatic field (slow field changes), radiation field (fast field changes) and magnetic field affiliated with charge movement.…”