Characteristics of Negative Cloud‐To‐Ground Flashes Observed in the Brazilian Amazon Region

Abstract

AbstractFeatures of negative cloud‐to‐ground (CG) flashes in the eastern Amazon region of Brazil, near the equator line, were analyzed from their wideband (160 Hz–10 MHz) electric field records acquired at the UFPA‐Lightning Research Laboratory in Belem, Para, Brazil in the rainy season of 2020. Records of CG flashes were synchronized in time with the Geostationary Lightning Mapper (GLM) data. We found that the GLM relative detection efficiency for negative CG flashes in the region of study is 78.5%. For a subset of 613 flashes that were detected by the GLM, we segregate the events into three categories (close‐, intermediate‐ and distant‐range) according to the GLM reported locations. Flash multiplicity, interstroke time interval, flash duration, leader duration, preliminary‐breakdown (PB) pulse train duration, PB to first return‐stroke (RS) time interval, and the ratio of PB to first RS are determined for 781 negative CG flashes containing 2,383 strokes. The results were compared with previous results obtained in different parts of the globe with an emphasis on studies performed in similar regions such as in the tropics. For all flashes, the average number of strokes per flash is 3.1 and the percentage of single‐stroke flash is 30%. The geometric mean of interstroke intervals, flash duration, PB to first RS time interval, and PB pulse train duration are 63, 186, 10, and 1.5 ms, respectively.