Thunderstorms without tropopause penetration in Central Africa produce cloud-top jet events

Using multi-satellite observations, we examined 20 upward discharge events from thunderstorms (15 blue jets (BJs)/blue starters (BSs) and 5 gigantic jets (GJs)) observed by ISUAL (Imager of Sprites and Upper Atmospheric Lightning) between 2009 and 2015. Our analyses reveal that these BJ/BS and GJ discharges consistently originated from thunderstorms with vigorous convection, strong mixed-phase microphysics, and high CAPE (convective available potential energy) of greater than 1000 J kg −1 in most cases, yet cloud tops remained 1–3 km below the 16–17 km tropical tropopause. Notably, one GJ emerged from a shallow thunderstorm with exceptionally low CAPE (∼140 J kg −1 ) and cloud tops of only ∼6 km, exposing previously unrecognized initiation pathways. It is concluded that thunderstorms in Central Africa can produce BJ/BSs and GJs without penetrating the tropopause, challenging the prevailing overshooting-top paradigm that has dominated jet initiation theory. Our results demonstrate that tropopause penetration is probably not a prerequisite for jet production and identify Central Africa as a critical natural laboratory for advancing our understanding of troposphere–ionosphere coupling and the dynamics of transient luminous events. 利用多颗卫星协同观测研究了2009-2015年由ISUAL (精灵与中高层大气放电成像仪) 记录的20次雷暴上行放电事件 (其中15次为蓝色喷流/蓝色启辉器, 5次为巨大喷流) .分析显示, 这些喷流事件几乎都起源于具有强对流,显著混合相态微物理过程且对流有效位能 (CAPE) 普遍大于1000 J kg -1 的雷暴, 但其云顶高度仍比热带对流层顶16–17 km低1–3 km.值得注意的是, 我们发现一例巨大喷流源自一场发展高度较低的雷暴, 其CAPE较低 (约140 J kg -1) , 云顶仅高约6 km, 展现了此前未被认知的喷流起始路径.研究结果表明, 中非地区的雷暴在未穿透对流层顶的情况下也能产生喷流事件, 这一结果挑战了长期主导喷流起始理论的“过冲云顶”范式, 说明雷暴穿透对流层顶很可能并非喷流产生的必要条件, 同时凸显了中非是推进对流层—电离层耦合以及瞬态发光事件动力学认识的天然实验室.