A Study of Preliminary Breakdown and Return Stroke Processes in High-Intensity Negative Lightning Discharges

Atmosphere

Vladimir A. Rakov¹  Yanan Zhu¹  Manh D. Tran¹ 

[1] Department of Electrical and Computer Engineering, University of Florida, 1064 Center Drive, Gainesville, FL 32611, USA;

关键词: negative cloud-to-ground lightning;    preliminary breakdown;    stepped leader;    return stroke;    electric field waveforms;   

DOI  :  10.3390/atmos7100130

来源: DOAJ

【 摘 要 】

Using an automated data processing algorithm, we examined electric field records of 5498 negative cloud-to-ground flashes reported by the U.S. National Lightning Detection Network (NLDN) within 50 to 500 km of the Lightning Observatory in Gainesville (LOG), Florida. Out of the 5498 flashes, 3496 (64%) had detectable preliminary breakdown (PB) pulse trains. Only 3077 flashes with a single PB pulse train and NLDN-reported first-return-stroke (RS) peak current ≥50 kA were selected for detailed analysis. The arithmetic mean values of PB pulse train duration, PB-RS interval, and PB/RS pulse peak ratio were 2.7 ms, 8.8 ms, and 0.15, respectively. The PB-RS interval was found to decrease with increasing RS peak current (Spearman correlation coefficient was statistically significant and equal to −0.80). The range-normalized PB pulse peak exhibited statistically significant positive correlation with the RS peak current, with Spearman correlation coefficient being 0.48. Thus, it appears that the high-intensity (≥50 kA) negative lightning is characterized by shorter (and, by inference, faster) stepped leaders and more pronounced PB pulse trains.

【 授权许可】

Unknown