The 2019–2020 Australian wildfire crisis broke the historical bushfire record and heavily contaminated the continental and offshore atmosphere. This study found that lightning strokes increase considerably, by 73% over land and 270% over ocean, during the wildfire season. Thermodynamic parameters support a weaker forcing, unfavorable for frequent lightning activity over ocean. Clear augmentation of smaller cloud ice particles is identified with aerosol, while cloud liquid water path changes are feeble over ocean. Added aerosol invigorates positive intra‐cloud (IC) strokes and negative cloud‐to‐ground (CG) strokes in moist oceanic convection and facilitates a noticeable positive correlation between precipitation and lightning strokes. Rainfall events accompanied by lightning increase by 240% with added aerosol. Aerosol advected from land to ocean can lead to a larger hydrometeor concentration and smaller‐size ice crystals above the freezing level and thereby, invigorate convective strength systematically to stimulate more frequent and more robust mixed‐phase development, energizing the lightning discharge process.
This content will become publicly available on January 11, 2025
We observed two Terrestrial Gamma‐ray Flashes (TGFs) in Uchinada, Japan associated with negative cloud‐to‐ground lightning strokes exactly 1 year apart on 18 December 2020 and 2021. The events were remarkable for their lateral distance from the associated strokes—each about 5 km away from the detector site. Not only was that lateral distance remarkable on its own for a ground based detection, but the low‐altitude profile of winter thunderstorms in Japan would suggest the detections occurred at unprecedented nadir angles—73.3° off axis for the 2020 event with the standard assumption of a vertically oriented TGF. Unsurprisingly, Monte Carlo simulations of the straightforward interpretation of these events yield fluences 2 orders of magnitude lower than observed data. We investigate a variety of ways to attempt to resolve the contradiction between expected and observed behavior.
more » « less- Award ID(s):
- 2235299
- PAR ID:
- 10485471
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Atmospheres
- Volume:
- 129
- Issue:
- 2
- ISSN:
- 2169-897X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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