Observation of compact intracloud discharges using VHF broadband interferometers: CHARACTERISTICS OF CID CHANNELS

[1] Compact intracloud discharge (CID) is a distinct intracloud lightning discharge characterized by strong VHF emissions, and it is one of the most mysterious lightning events. In this paper the CID channel evolution images obtained by using VHF broadband interferometers are presented for the first time. Analysis of 11 CIDs shows that the channels of CIDs develop mainly in a vertical direction. The vertical scale of CIDs is in the range of 0.40–1.9 km. The average duration of VHF broadband emissions is 15 μs. The average apparent speed of CIDs is in a range of 0.44–1.0 × 108 m/s with a mean value of 0.61 × 108 m/s. The temporal-spatial evolution of the radiation sources of the CID shows an oscillation pattern, confirming the previous prediction that there is an oscillating current being reflected at the two ends of the CID channel. The estimated speed of the current wave in the CID channel is in a range of 0.56–2.6 × 108 m/s with a mean value of 1.4 × 108 m/s.

[1]  X. Shao,et al.  Estimating lightning channel characteristics of positive narrow bipolar events using intrachannel current reflection signatures , 2007 .

[2]  K. Eack.  Electrical characteristics of narrow bipolar events , 2004 .

[3]  Paul Krehbiel,et al.  Observations of VHF source powers radiated by lightning , 2001 .

[4]  Wansheng Dong,et al.  Broadband interferometer observations of a triggered lightning , 2001 .

[5]  Ting Wu,et al.  Comparison of positive and negative compact intracloud discharges , 2011 .

[6]  T. E. Light,et al.  Bimodal radio frequency pulse distribution of intracloud-lightning signals recorded by the FORTE satellite , 2003 .

[7]  Paul Krehbiel,et al.  A GPS‐based three‐dimensional lightning mapping system: Initial observations in central New Mexico , 1999 .

[8]  Helin Zhou,et al.  Estimation of channel characteristics of narrow bipolar events based on the transmission-line model , 2010 .

[9]  Wansheng Dong,et al.  Observations on the leader-return stroke of cloud-to-ground lightning with the broadband interferometer , 2002 .

[10]  Helin Zhou,et al.  Observations of narrow bipolar events in East China , 2010 .

[11]  David M. Le Vine,et al.  Sources of the strongest RF radiation from lightning , 1980 .

[12]  David A. Smith,et al.  A distinct class of isolated intracloud lightning discharges and their associated radio emissions , 1999 .

[13]  Xiushu Qie,et al.  Using lightning locating system based on time-of-arrival technique to study three-dimensional lightning discharge processes , 2010 .

[14]  David M. Suszcynsky,et al.  Coordinated observations of optical lightning from space using the FORTE photodiode detector and CCD imager , 2001 .

[15]  D. M. Suszcynsky,et al.  Narrow Bipolar Events as indicators of thunderstorm convective strength , 2003 .

[16]  Vladimir A. Rakov,et al.  Compact intracloud lightning discharges: 1. Mechanism of electromagnetic radiation and modeling , 2010 .

[17]  Abram R. Jacobson,et al.  A method for determining intracloud lightning and ionospheric heights from VLF/LF electric field records , 2004 .

[18]  Shi Qiu,et al.  An improved method for broadband interferometric lightning location using wavelet transforms , 2009 .

[19]  Vladimir A. Rakov,et al.  On phenomenology of compact intracloud lightning discharges , 2010 .

[20]  Vladimir A. Rakov,et al.  Compact intracloud lightning discharges: 2. Estimation of electrical parameters , 2010 .

[21]  Jeffrey C. Bailey,et al.  A class of unusual lightning electric field waveforms with very strong high‐frequency radiation , 1989 .