High-Speed Camera Observation of a Cloud-to-ground Flash from a Tropical Thunderstorm

This study investigates the dynamics of a negative cloud-to-ground (CG) lightning flash captured during a tropical thunderstorm in Malaysia using a high-speed camera operating at 1057 frames per second and electromagnetic field sensors. Detailed analyses of the flash, including its channel length, return stroke speed, inter-stroke intervals, and peak current, were conducted. The lightning flash consisted of four return strokes, with channel lengths measured as 3.3 km for the first three strokes and 6.7 km for the fourth. Return stroke speeds ranged from <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1.37 \times 10^{8} ~\mathrm{m} / \mathrm{s}$</tex> to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$1.85 \times 10^{8} ~\mathrm{m} / \mathrm{s}$</tex>, and peak currents were estimated between 1.44 kA and 2.72 kA. Inter-stroke intervals varied from 7.57 ms to 19.87 ms. High-speed camera observations and electric field measurements showed a strong correlation, with an average time error of 4.6 %. The findings demonstrate the utility of combining high-speed imaging and electromagnetic field measurements for precise lightning analysis, contributing to advancements in understanding lightning dynamics in tropical thunderstorms. This methodology can be extended to study positive CG and intracloud lightning under diverse meteorological conditions, offering insights for improving lightning protection and disaster risk management systems.