Lightning Discharges Producing Pulse Trains Indicative of Preliminary Breakdown in Cloud-to-Ground Lightning But Not Followed by Return Strokes
In this study, we identify and examine electric field pulse trains that are characteristic of preliminary breakdown in negative cloud-to-ground discharges, but are not followed by return-stroke waveforms. We refer to these events as “attempted cloud-to-ground leaders, although some of them were followed by full-fledged cloud discharges. Note that in the latter case polarity of the initial half-cycle of preliminary-breakdown-type pulses was the same as that of negative return-stroke pulses and opposite to the polarity of pulses characteristic of the initial breakdown in cloud discharges. We examined a total of 2475 electric field records of lightning events acquired in Gainesville, Florida, in 2006, and waveforms in 33 of them were found to satisfy criteria set for attempted cloud-to-ground leaders (with detectable preliminary-breakdown pulse trains). The preliminary-breakdown pulses associated with attempted leaders have durations that may satisfy NLDN criteria set for return strokes in negative cloud-to-ground flashes. As a result, some of the attempted cloud-to-ground leaders, which should belong to the cloud discharge category, can be misclassified by the NLDN, as negative cloud-to-ground discharges. Although the pulse trains considered here are rare (less than 1.5％ of the examined 2475 Florida electric field records), they might contribute significantly to the lower-intensity contamination of the NLDN output for negative flashes.
Amitabh Nag Vladimir A. Rakov
Department of Electrical and Computer Engineering, University of Florida,P.O. Box 116130, Gainesville, FL 32611-6130, USA
国际会议
第13届国际大气电学会议(The 13th International Conference on Atmospheric Electricity)
北京
英文
2007-08-13（万方平台首次上网日期，不代表论文的发表时间）