A Novel Stroke to Flash Clustering Algorithm to Investigate Storm Coupling

Abstract:

Recent statistical studies have revealed with greater resolution the time and distance distributions of strokes within a lightning flash. Stroke to flash clustering algorithms stand to benefit greatly from the results of this research. The goal of this study is to develop a novel stroke to flash clustering algorithm that more accurately captures the observed patterns in cloud to ground (CG) lightning. First, we compare previous algorithms using National Lightning Detection Network (NLDN) stroke data through statistical methods with the assumption that flash inter-arrival times should be uniform. With this result and the knowledge of the distance versus time distributions of strokes, we propose a new algorithm to cluster strokes into flashes that preserves the uniformity of flash inter-arrival times. This novel algorithm allows for further studies of lightning flashes without added bias from previous stroke to flash clustering methods. One such investigation involves recent studies on spatially separated storms and storm cells that exhibit flash synchronization due to electrical coupling. We use our newly developed algorithm to further explore the validity of this phenomenon. Our results show that the new method to cluster strokes to flashes successfully results in uniform flash inter-arrival times and also fails to find any significant link or synchronicity with regards to storm coupling.