Testing the hypothesis of lightning initiation by runaway air breakdown with ALOFT data

Martino Marisaldi; Nikolai Østgaard; Andrey Mezentsev; David Sarria; Nikolai Lehtinen; Ingrid Bjørge-Engeland; Anders Fuglestad; Øystein Færder; Timothy J. Lang; Mason Quick; Richard Blakeslee; Hugh Christian; J. Eric Grove; Daniel Shy; Steven A. Cummer; Yunjiao Pu; Marni Pazos

doi:https://doi.org/10.5194/egusphere-egu25-18036

[Back] [Session NH1.6]

EGU25-18036, updated on 15 Mar 2025

https://doi.org/10.5194/egusphere-egu25-18036

EGU General Assembly 2025

© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.

Poster | Tuesday, 29 Apr, 10:45–12:30 (CEST), Display time Tuesday, 29 Apr, 08:30–12:30

Hall X3, X3.10

Testing the hypothesis of lightning initiation by runaway air breakdown with ALOFT data

Martino Marisaldi¹, Nikolai Østgaard¹, Andrey Mezentsev¹, David Sarria¹, Nikolai Lehtinen¹, Ingrid Bjørge-Engeland¹, Anders Fuglestad¹, Øystein Færder¹, Timothy J. Lang², Mason Quick², Richard Blakeslee², Hugh Christian³, J. Eric Grove⁴, Daniel Shy⁴, Steven A. Cummer⁵, Yunjiao Pu⁵, and Marni Pazos⁶

Martino Marisaldi et al.

¹University of Bergen, Department of Physics and Technology, Bergen, Norway (martino.marisaldi@uib.no)
²NASA Marshall Space Flight Center, Huntsville, AL, USA
³Department of Atmospheric Science, Earth System Science Center, University of Alabama in Huntsville, Huntsville, AL, USA
⁴U.S. Naval Research Laboratory, Washington, DC, USA
⁵Duke University, Durham, NC, USA
⁶Instituto de Ciencias de la Atmósfera y Cambio Climático, National Autonomous University of Mexico (UNAM), Mexico City, Mexico

Lightning initiation is one of the top unsolved problems in atmospheric electricity. Runaway electron breakdown of air has been suggested to play a key role in lightning initiation, by locally enhancing the ambient electric field above the conventional breakdown threshold. The recent results from the ALOFT flight campaign have shown a tight interconnection between highly convective cores, lightning activity, and high-energy particle acceleration observed as a wide range of gamma-ray phenomena (gamma-ray glows, Terrestrial Gamma-ray Flashes, and the recently reported Flickering Gamma-ray Flashes). Thanks to the combination of simultaneous, high-sensitivity gamma-ray, optical and radio measurements, the ALOFT dataset provides a unique opportunity to investigate the lightning initiation problem and test the runaway breakdown hypothesis. Here we focus on the lightning discharges observed within the field of view of the gamma-ray instrument and not associated to any detectable gamma-ray enhancement. We will try to answer the following questions: how many discharges are there unambiguously not associated to gamma-rays? What are the characteristics of these discharges? What can we infer about the hypothesis of lightning initiation triggered by runaway air breakdown?

How to cite: Marisaldi, M., Østgaard, N., Mezentsev, A., Sarria, D., Lehtinen, N., Bjørge-Engeland, I., Fuglestad, A., Færder, Ø., Lang, T. J., Quick, M., Blakeslee, R., Christian, H., Grove, J. E., Shy, D., Cummer, S. A., Pu, Y., and Pazos, M.: Testing the hypothesis of lightning initiation by runaway air breakdown with ALOFT data, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18036, https://doi.org/10.5194/egusphere-egu25-18036, 2025.