Gigantic jets produced by an isolated tropical thunderstorm near Réunion Island

Abstract

[1] Five gigantic jets (GJs) have been recorded with video and photograph cameras on 7 March 2010 above an isolated tropical storm east of Réunion Island. Three of them were produced before the storm reached its coldest cloud top temperature (approximately −81°C), and two others occurred during the cloud extension. Thanks to the close distance of observation (∼50 km), the luminosity within the cloud was recorded, and the events are analyzed in unprecedented detail. The tops of the GJs are estimated between 80 and 90 km. All these GJs are accompanied by long, continuous cloud illumination, and they are preceded and followed by intermittent optical flashes from the cloud, most of time without any cloud-to-ground (CG) flash simultaneously detected, which suggests they originated mainly as intracloud discharges and without any charge transfer to Earth. The CG lightning activity is observed to cease a few tens of seconds before the jets. According to ELF data recorded at Nagycenk, Hungary, the five GJs serve to raise negative charge. Their duration ranges from 333 to 850 ms. The leading jet has the most variable duration (33-167 ms) and propagates faster at higher altitudes. The trailing jet exhibits a continuous decrease of luminosity in different parts of the jet (lower channel, transition zone and, for most events, carrot sprite-like top) and in the cloud, with possible rebrightening. The lower channels (∼20-40 km altitude) produce blue luminosity which decreases with altitude and become more and more diffuse with time. The transition zone (around 40-65 km) consists of bright red, luminous beads slowly going up (∼10 4 m s −1), retracing the initial leading jet channels.Citation: Soula, S., O. van der Velde, J. Montanya, P. Huet, C. Barthe, and J. Bór (2011), Gigantic jets produced by an isolated tropical thunderstorm near Réunion Island,

A gigantic jet event observed over a thunderstorm in mainland China

“…Even so, +CG flash rate was still much lower than that of Van der Velde et al [19]. Results in Soula et al [22] showed that no CGs occurred in tens of seconds before the GJ, and they suspected that the GJ was caused by intracloud lightning, in agreement with results obtained by Krehbiel et al [28], which was published in Nature. Further analysis on lightning location network data shows that 25 negative CGs occurred in 20 seconds before the GJ.…”

“…Three of the five gigantic jets occurred before the storm reached its coldest cloud top temperature (-81°C) and the other two occurred during the cloud extension. The extremely low frequency (ELF) data showed that the five gigantic jets reported by Soula et al [22] were also negative discharges.…”

“…Thereafter, Van der Velde et al [19], Cummer et al [20], and Chou et al [21] reported gigantic jet observations, re-spectively. However, Soula et al [22] reported five gigantic jets over an isolated thunderstorm.…”

“…This gigantic jet was the first recorded Type-II gigantic jet from the ground (classifications of gigantic jet are given in section 2). Soula et al [22] studied five gigantic jets observed at a very close distance of 50 km. Three of the five gigantic jets occurred before the storm reached its coldest cloud top temperature (-81°C) and the other two occurred during the cloud extension.…”

A Thermodynamic, kinematic and microphysical analysis of a jet and gigantic jet‐producing Florida thunderstorm

“…Early studies indicated that these events might be exclusively maritime [Su et al, 2003]. While this is no longer the case, jet events do appear to have a predilection for tropical disturbances [e.g., Cummer et al, 2009;Soula et al, 2011;Lu et al, 2011;Huang et al, 2012] and oceanic convection in general [van der Velde et al, 2010]. In contrast to jets, there is no direct evidence of a conductive current path to the cloud top below sprites, elves, or halos.…”