Upward propagation of gigantic jets revealed by 3D radio and optical mapping

Abstract

Occasionally, lightning will exit the top of a thunderstorm and connect to the lower edge of space, forming a gigantic jet. Here, we report on observations of a negative gigantic jet that transferred an extraordinary amount of charge between the troposphere and ionosphere (∼300 C). It occurred in unusual circumstances, emerging from an area of weak convection. As the discharge ascended from the cloud top, tens of very high frequency (VHF) radio sources were detected from 22 to 45 km altitude, while simultaneous optical emissions (777.4 nm OI emitted from lightning leaders) remained near cloud top (15 to 20 km altitude). This implies that the high-altitude VHF sources were produced by streamers and the streamer discharge activity can extend all the way from near cloud top to the ionosphere. The simultaneous three-dimensional radio and optical data indicate that VHF lightning networks detect emissions from streamer corona rather than the leader channel, which has broad implications to lightning physics beyond that of gigantic jets.

High Production of Gigantic Jets by a Thunderstorm Over Indian Ocean

“…(2011) also with 5 jet events in one hour, Boggs et al. (2019) with 11 jet events within 5 hr, and even less for other studies (Boggs et al., 2022; Liu et al., 2015). All jet events were visually found to reach between 85 and 89 km of altitude which is well in the range found by Peng et al.…”

“…Six jets were triangulated thanks to several cameras, one of which was a multiple-jet event. Other cases of observations report much less events for one storm, as for example, Su et al (2003) with 5 jet events, Soula et al ( 2011) also with 5 jet events in one hour, Boggs et al (2019) with 11 jet events within 5 hr, and even less for other studies (Boggs et al, 2022;Liu et al, 2015). All jet events were visually found to reach between 85 and 89 km of altitude which is well in the range found by Peng et al (2018) who could triangulate several jet events and therefore better determine the distance for an accurate evaluation of the top height.…”

“…In that case, the detections suggest strong +IC flash initiations occurring in a stronger electric field region between the central negative and upper positive charge region. Gigantic jets may develop as a second stage of an intracloud discharge, as shown by Lu et al (2011) and Boggs et al (2022) using VHF Lightning Mapping Arrays. The initial upper level negative leader may neutralize the positive charge and pave the way for the GJ development (as a negative leader escaping the upper cloud charge region) by creating an imbalance in the vertical charge distribution (Krehbiel et al, 2008) available to the remainder of the discharge.…”

“…(2011) and Boggs et al. (2022) using VHF Lightning Mapping Arrays. The initial upper level negative leader may neutralize the positive charge and pave the way for the GJ development (as a negative leader escaping the upper cloud charge region) by creating an imbalance in the vertical charge distribution (Krehbiel et al., 2008) available to the remainder of the discharge.…”

“…However, van der Velde et al ( 2022) recorded 70 cases of GJ occurring in Colombia (tropical region), between 2016 and 2022 for most of them, and found a majority over land, and Singh et al (2017) reported 4 GJ over India, far from the coast. Other cases, most of the time with one GJ event, were reported outside the tropics, mostly in or around the southern United States, but sometimes related to tropical airmass (Boggs et al, 2022;Cummer et al, 2009;Lazarus et al, 2015;Meyer et al, 2013;van der Velde et al, 2007). Different from tropical GJs, shallow winter thunderstorms in mid-latitude regions are sometimes capable of producing GJ as well (van der Velde et al, 2010).…”