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 single-strokes, 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