COMPARISON OF ACOUSTIC LOCATION, VHF MAPPING, AND HIGH-SPEED VIDEO RECORDINGS OF LIGHTNING FLASHES

摘要

In this study we compare acoustic source location results for a triggered lightning flash showing good agreement with VHF mapping by the Lightning Mapping Array (LMA) and with high-speed video recordings. A low cost acoustic array consisting of a GPS-synchronized data-logger and four acoustic pressure sensors proves to be a good lightning mapping system for flashes occurring at distances up to 12 km from the array. The luminous channel that carries continuous current and remains luminous for hundreds of ms produces acoustic sources, located by the acoustic array, while other branches that appear dark produce dart leaders but no acoustic sources are located in those channels; suggesting that the two types of branches come from different physical processes or are heated differently.