While narrow bipolar events (NBEs) could be related with lightning initiation, their intrinsic physics remains in question. Here we report on optical measurements by the Atmosphere‐Space Interactions Monitor (ASIM) on the International Space Station (ISS) of blue flashes associated with NBEs. They are observed in a narrow blue band centered at 337 nm, with no simultaneous activity at 777.4 nm, considered a strong lightning emission line. From radio waves measured from the ground, we find that 7 of 10 single‐pulse blue events can be identified as positive NBEs. The source altitudes estimated from optical and radio signals agree and indicate that the sources of the blue flashes are located between ∼8.5 and ∼14 km, in a cloud reaching 14–15 km altitude. The observations suggest that single‐pulse blue flashes are from cold ionization waves, so‐called streamers, and that positive NBEs are corona discharges formed by many streamers.

中文翻译：

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ASIM对窄双极事件的蓝色光学观测表明雷暴中的电晕流光活动

虽然狭窄的双极事件（NBE）可能与雷电引发有关，但它们的内在物理仍存在疑问。在这里，我们报告了国际空间站（ISS）上的大气-空间相互作用监测器（ASIM）进行的与NBE相关的蓝色闪烁的光学测量。在以337 nm为中心的窄蓝带中观察到它们，而在777.4 nm处没有同时活动，被认为是强雷电发射线。从地面测得的无线电波中，我们发现10个单脉冲蓝色事件中有7个可以识别为正NBE。从光学和无线电信号估计源海拔同意并指示该蓝色闪烁的源位于之间〜 8.5和〜14公里，在达到14-15公里的高度的云中。这些观察结果表明，单脉冲蓝闪光来自冷的电离波，即所谓的拖缆，而正NBE则是由许多拖缆形成的电晕放电。