Day-to-day differences in the characterization of lightning observed by multiple high-speed cameras

Abstract This study aims to analyze how the visible parameters of cloud-to-ground discharges such as the flash multiplicity and duration, the interstroke interval, the continuing current duration and the number of ground contacts per flash vary between observations conducted on different days. Several authors have already analyzed these parameters for groups of thunderstorms in some regions. Although some authors did not find differences on those characteristics for different regions, there has not been a comprehensive amount of lightning recordings from the same thunderstorm in order to evaluate such parameters in a storm-to-storm basis. The lightning data for this work was obtained by four high-speed cameras set to operate at 2500 frames per second. They were located in Sao Jose dos Campos, Brazil, and in its neighboring region as part of the RAMMER project (Portuguese acronym for Automated Multi-Camera Network for Monitoring and Study of Lightning Flashes). Five thunderstorm days were selected for this study, during which a total of 361 flashes were recorded. This is the first study in which four high-speed cameras observed the same thunderstorm from different locations. Because of the number of cameras and their positions, the coverage area is larger than usual single-camera studies, thereby increasing the number of flashes recorded from the same thunderstorm. These larger samples allow a more representative analysis of the lightning parameters mentioned above.