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JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, D20104, doi:10.1029/2007JD008575, 2007

Analysis of the first gigantic jet recorded over continental North America

Oscar A. van der Velde

Laboratoire d'Aérologie, CNRS, Université de Toulouse, Toulouse, France


Walter A. Lyons

FMA Research, Inc., Fort Collins, Colorado, USA


Thomas E. Nelson

FMA Research, Inc., Fort Collins, Colorado, USA


Steven A. Cummer

Electrical and Computer Engineering Department, Duke University, Durham, North Carolina, USA


Jingbo Li

Electrical and Computer Engineering Department, Duke University, Durham, North Carolina, USA


James Bunnell

Benbrook, Texas, USA


Abstract

Two low-light cameras near Marfa, Texas, recorded a gigantic jet over northern Mexico on 13 May 2005 at approximately 0423:50 UTC. Assuming that the farthest of two candidate storm systems was its source, the bright lower channel ended in a fork at around 50–59 km height with the very dim upper branches extended to 69–80 km altitude. During the time window containing the jet, extremely low frequency magnetic field recordings show that there was no fast charge moment change larger than 50 coulomb times kilometers (C km) but there was a larger and slower charge moment change of 520 C km over 70 ms. The likely parent thunderstorm was a high-precipitation supercell cluster containing a persistent mesocyclone, with radar echo tops of at least 17 km. However, photogrammetric analysis suggests that the gigantic jet occurred over the forward flank downdraft region with echo tops of 14 km. This part of the supercell may have had an inverted-polarity charge configuration as evidenced by positive cloud-to-ground lightning flashes (+CG) dominating over negative flashes (−CG), while −CGs occurred under the downwind anvil. Four minutes before the gigantic jet, −CG activity practically ceased in this area, while +CG rates increased, culminating during the 20 s leading up to the gigantic jet with four National Lightning Detection Network–detected +CGs. A relative lull in lightning activity of both polarities was observed for up to 1.5 min after the gigantic jet. The maturing storm subsequently produced 30 sprites between 0454 and 0820 UTC, some associated with extremely large impulse charge moment change values.

Received 22 February 2007; accepted 20 June 2007; published 17 October 2007.

Keywords: gigantic jet; supercell; lightning.

Index Terms: 3304 Atmospheric Processes: Atmospheric electricity; 3324 Atmospheric Processes: Lightning; 2427 Ionosphere: Ionosphere/atmosphere interactions (0335); 3314 Atmospheric Processes: Convective processes; 2411 Ionosphere: Electric fields (2712).

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Citation: van der Velde, O. A., W. A. Lyons, T. E. Nelson, S. A. Cummer, J. Li, and J. Bunnell (2007), Analysis of the first gigantic jet recorded over continental North America, J. Geophys. Res., 112, D20104, doi:10.1029/2007JD008575.