Smith Deirdre, Trepanier Jill, Alnussirat Samer T, Cherry Michael L, Legault Marc D, Pleshinger Donald J
Department of Geography & Anthropology Louisiana State University Baton Rouge LA USA.
Department of Physics & Astronomy Louisiana State University Baton Rouge LA USA.
J Geophys Res Atmos. 2021 Aug 16;126(15):e2020JD033765. doi: 10.1029/2020JD033765. Epub 2021 Jul 27.
The terrestrial gamma-ray flash (TGF) and Energetic Thunderstorm Rooftop Array (TETRA-II) detected 22 X-ray/gamma-ray flash events associated with lightning between October 2015 and March 2019 across three ground-based detector locations in subtropical and tropical climates in Louisiana, Puerto Rico, and Panama. Each detector array consists of a set of bismuth germanate scintillators that record X-ray and gamma-ray bursts over the energy range 50 keV-6 MeV (million electron volts). TETRA-II events have characteristics similar to both X-ray bursts associated with lightning leaders and TGFs: sub-millisecond duration, photons up to MeV energies, and association with nearby lightning (typically within 3 km). About 20 of the 22 events are geolocated to individual lightning strokes via spatiotemporally coincident sferics. An examination of radar reflectivity and derived products related to events located within the Next Generation Weather Radar (NEXRAD) monitoring region indicates that events occur within mature cells of severe and non-severe multicellular and squall line thunderstorms, with core echo tops which are at or nearing peak altitude. Events occur in both high lightning frequency thunderstorm cells and low lightning frequency cells. Events associated with high frequency cells occur within 5 min of significant lightning jumps. Among NEXRAD-monitored events, hail is present within 8 km and 5 min of all except a single low-altitude cold weather thunderstorm. An association is seen with maximum thunderstorm development, lightning jumps, and hail cells, indicating that the TETRA-II X-ray/gamma-ray events are associated with the peak storm electrification and development of electric fields necessary for the acceleration of electrons to high energies.
地面伽马射线闪光（TGF）和高能雷暴屋顶阵列（TETRA-II）在2015年10月至2019年3月期间，于路易斯安那州、波多黎各和巴拿马的亚热带和热带气候区的三个地面探测器位置，检测到22次与闪电相关的X射线/伽马射线闪光事件。每个探测器阵列由一组锗酸铋闪烁体组成，可记录能量范围在50千电子伏特至6兆电子伏特（百万电子伏特）的X射线和伽马射线爆发。TETRA-II事件具有与闪电先导相关的X射线爆发和TGFs相似的特征：亚毫秒持续时间、高达兆电子伏特能量的光子，以及与附近闪电的关联（通常在3公里内）。通过时空重合的天电，22次事件中的约20次被定位到单个雷击。对与下一代天气雷达（NEXRAD）监测区域内事件相关的雷达反射率和衍生产品的检查表明，这些事件发生在严重和非严重多细胞及飑线雷暴的成熟细胞内，其核心回波顶处于或接近峰值高度。事件发生在高闪电频率雷暴细胞和低闪电频率细胞中。与高频细胞相关的事件发生在显著闪电跳跃的5分钟内。在NEXRAD监测的事件中，除了一次低空寒冷天气雷暴外，所有事件在8公里范围内和5分钟内都有冰雹。可以看到与最大雷暴发展、闪电跳跃和冰雹细胞之间存在关联，这表明TETRA-II X射线/伽马射线事件与风暴电气化峰值以及将电子加速到高能所需的电场发展有关。
