Highly dynamic gamma-ray emissions are common in tropical thunderclouds

• 成果类型: Article
• 署名作者: Marisaldi, M.; Ostgaard, N.; Mezentsev, A.; Lang, T.; Grove, J. E.; Shy, D.; Heymsfield, G. M.; Krehbiel, P.; Thomas, R. J.; Stanley, M.; Sarria, D.; Schultz, C.; Blakeslee, R.; Quick, M. G.; Christian, H.; Adams, I.; Kroodsma, R.; Lehtinen, N.; Ullaland, K.; Yang, S.; Qureshi, B. Hasan; Sondergaard, J.; Husa, B.; Walker, D.; Bateman, M.; Mach, D.; Cummer, S.; Pazos, M.; Pu, Y.; Bitzer, P.; Fullekrug, M.; Cohen, M.; Montanya, J.; Younes, C.; van der Velde, O.; Roncancio, J. A.; Lopez, J. A.; Urbani, M.; Santos, A.
• 署名单位: University of Bergen; Istituto Nazionale Astrofisica (INAF); National Aeronautics & Space Administration (NASA); NASA Marshall Space Flight Center; United States Department of Defense; United States Navy; United States Naval Research Laboratory; National Aeronautics & Space Administration (NASA); NASA Goddard Space Flight Center; New Mexico Institute of Mining Technology; University of Alabama System; University of Alabama Huntsville; Universities Space Research Association (USRA); Duke University; Universidad Nacional Autonoma de Mexico; University of Bath; University System of Georgia; Georgia Institute of Technology; Universitat Politecnica de Catalunya; Universidad Nacional de Colombia
• 刊物名称: Nature
• ISSN/ISSBN: 0028-3786
• DOI: 10.1038/s41586-024-07936-6
• 发表日期: 2024-10-03
• 关键词: x-rays; thunderstorm; aircraft; flashes

摘要

Thunderstorms emit fluxes of gamma rays known as gamma-ray glows1,2, sporadically observed by aircraft1,3-7, balloons8-11 and from the ground12-18. Observations report increased gamma-ray emissions by tens of percent up to two orders of magnitude above the background, sometimes abruptly terminated by lightning discharges1,3-5. Glows are produced by the acceleration of energetic electrons in high-electric-field regions within thunderclouds8 and contribute to charge dissipation3. Glows had been considered as quasi-stationary phenomena3,5,12, with durations up to a few tens of seconds and spatial scales up to 10-20 km. However, no measurements of the full extension in space and time of a gamma-ray-glow region and their occurring frequency have been reported so far. Here we show that tropical thunderclouds over ocean and coastal regions commonly emit gamma rays for hours over areas up to a few thousand square kilometres. Emission is associated with deep convective cores; it is not uniform and continuous but shows characteristic timescales of 1-10 s and even subsecond for individual glows. The dynamics of gamma-glowing thunderclouds strongly contradicts the quasi-stationary picture of glows and instead resembles that of a huge gamma-glowing 'boiling pot' in both pattern and behaviour. Tropical thunderclouds over ocean and coastal regions are shown to emit gamma rays for several hours over areas of up to a few thousand square kilometres, contradicting the quasi-stationary picture of glows.