Open AccessEstimation of channel characteristics of narrow bipolar events based on the transmission‐line model
Author(s) -
Zhu Baoyou,
Zhou Helin,
Ma Ming,
Lv Fanchao,
Tao Shanchang
Publication year - 2010
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2009jd012021
Subject(s) - waveform , amplitude , attenuation , channel (broadcasting) , physics , lightning (connector) , transmission line , radiation , transmission (telecommunications) , computational physics , optics , acoustics , telecommunications , computer science , voltage , power (physics) , quantum mechanics
Narrow bipolar event (NBE) is a distinct class of intracloud lightning discharge, which is associated with the strongest radio frequency emissions and produces typical narrow bipolar radiation field waveforms. On the basis of the transmission‐line model, we introduce a direct technique to measure the time taken by the current front to propagate along the channel from distant radiation field pulses; the channel length of the NBE can then be estimated by multiplying this time by an assumed propagation speed. Our method involves integrating over the initial half cycle of narrow bipolar waveform of the NBE. The ratio of the integral result to the initial peak amplitude makes a good approximation to the time taken by the current front to travel along the channel, even though the current amplitude suffers heavy attenuation along the propagating channel. This method can be applied to all NBEs which produce narrow bipolar radiation field waveforms. Besides, if both the far radiation field and the near‐electrostatic field measurements were available, one could combine the method here and that of Eack (2004) to obtain the channel length of the NBE.