Thunderstorms emit fluxes of gamma rays known as gamma-ray glows^1,2, sporadically observed by aircraft^1,3,4,5,6,7, balloons^8,9,10,11 and from the ground^{12,13,14,15,16,17,18}. Observations report increased gamma-ray emissions by tens of percent up to two orders of magnitude above the background, sometimes abruptly terminated by lightning discharges^1,3,4,5. 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 phenomena^3,5,12, 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.

雷暴会发出称为伽马射线光^1,2 的伽马射线通量，飞机^1,3,4,5,6,7、气球^{8、9、10、11} 和地面^{12、13、14、15、16、17、18} 偶尔观察到。观测报告称，伽马射线发射增加了 10%，比背景高出两个数量级，有时会突然被雷电放电终止^1,3,4,5。辉光是由雷云⁸ 内高电场区域中的高能电子加速产生的，并有助于电荷耗散³。辉光被认为是准静止现象^3,5,12，持续时间长达几十秒，空间尺度可达 10-20 公里。然而，到目前为止，还没有关于伽马射线辉光区域在空间和时间上的完全延伸及其出现频率的测量报告。在这里，我们表明，海洋和沿海地区的热带雷云通常会在长达几千平方公里的区域内发射数小时的伽马射线。发射与深对流核心有关;它不是均匀和连续的，但显示出 1-10 秒甚至单个辉光的亚秒级特征时间尺度。伽马发光的雷云的动力学与发光的准静止图像强烈矛盾，相反，在模式和行为上都类似于一个巨大的伽马发光的“沸腾的锅”。