Liu Feifan, Neubert Torsten, Chanrion Olivier, Lu Gaopeng, Wu Ting, Lyu Fanchao, Lyu Weitao, Köhn Christoph, Li Dongshuai, Zhu Baoyou, Lei Jiuhou
CAS Key Laboratory of Geospace Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China.
CMA-USTC Laboratory of Fengyun Remote Sensing, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China.
Nat Commun. 2024 Aug 26;15(1):7344. doi: 10.1038/s41467-024-51705-y.
Blue corona discharges are often generated in thunderclouds penetrating into the stratosphere and are the optical manifestation of narrow bipolar events (NBEs) observed in radio signals. While their production appears to depend on convection, the cause and nature of such discharges are not well known. Here we show the observations by a lightning detection array of unusual amounts of 982 NBEs during a tropical storm on the coastline of China. NBEs of negative polarity are predominantly observed at the cloud top reaching the stratosphere, and positive NBEs are primarily at lower altitudes. We find that the dominant polarity changes with the typical time of development of thunderstorm cells, suggesting that the polarity depends on the phase of the storm cells. Furthermore, we find that the lightning jump of negative NBEs is associated with above-anvil cirrus plumes of ice crystals and water vapor in the lower stratosphere. We propose that variations in updrafts induce changes in the altitude and charge concentrations of the cloud layers, which lead to the polarity transition. Our results have implications for studies of the chemical perturbations of greenhouse gas concentrations by corona discharges at the tropopause.
蓝色电晕放电通常在穿透平流层的雷云中产生，是在无线电信号中观测到的窄双极事件（NBEs）的光学表现。虽然它们的产生似乎取决于对流，但这种放电的原因和性质尚不清楚。在这里，我们展示了中国海岸线一场热带风暴期间，闪电探测阵列对982次异常数量的NBEs的观测结果。负极性的NBEs主要在到达平流层的云顶观测到，而正极性的NBEs主要在较低高度观测到。我们发现主导极性随雷暴单体的典型发展时间而变化，这表明极性取决于雷暴单体的阶段。此外，我们发现负极性NBEs的闪电跃变与平流层下部冰晶和水汽的砧上卷云羽状物有关。我们提出上升气流的变化会引起云层高度和电荷浓度的变化，从而导致极性转变。我们的结果对研究对流层顶电晕放电对温室气体浓度的化学扰动具有启示意义。
