Observation of Isolated Breakdown Lightning Flashes in a Tropical Region

Abstract

The impact of lightning on humans and its threats on life and structures have encouraged the scientists to pursue study in this field. Lightning flash is a high current electric discharge that can be classified into five categories which are intra-cloud discharges, cloud to cloud, cloud to air, ground to cloud and cloud to ground discharges. Intra-cloud discharges have the main portion of the lightning flashes. The most damages and disturbances of lightning flashes are due to cloud to ground and ground to cloud flashes. The discharge phenomenon has various behaviors even in the same thunderstorm. The cloud to ground lightning discharge starts with preliminary breakdown pulses followed by leaders which cause return strokes. The subsequent strokes happen after the first return stroke in a typical lightning flash, but in few flashes the discharges do not lead to any subsequent strokes. This research investigates on these types of flashes which are called isolated breakdown lightning flashes, in Malaysia. The isolated breakdown flashes have rarely been seen in tropical regions compared with temperate areas. Among 150 selected waveforms on 9thMay 2013 in our measurement station, only 10 isolated lightning flashes were observed in our dataset, which make up less than 7% of total flashes in one thunderstorm.