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雷暴电荷结构产生巨大喷流
发布时间:2019-11-29
 

论文标题:Thunderstorm charge structures producing gigantic jets

作者:Levi D. Boggs, Ningyu Liu, Jeremy A. Riousset, Feng Shi, Steven Lazarus, Michael Splitt, Hamid K. Rassoul

数字识别码: s41598-018-36309-z

巨大喷流是从雷暴云上方传播到电离层下部的大气放电。其最初是雷暴云内部的闪电前导物,雷暴云电荷结构主要决定了前导物能否向上逃逸并形成巨大的喷流。目前,关于巨大喷流风暴源的雷暴云电荷结构,并没有观察性的研究结果被报道过。

在《科学报告》发表的Thunderstorm charge structures producing gigantic jets一文中,来自佛罗里达理工学院的Levi D. Boggs及其团队展示了气象观测和闪电模拟结果,以确定这些风暴可能的雷暴云电荷结构。电荷结构的特点是在强对流脉冲的末端附近形成一个狭窄的上部电荷区。对流脉冲会产生强烈的风暴顶部辐散和湍流,会有较大的风暴顶部径向速度差和谱宽。模拟结果表明,电荷结构产生与观测值高度匹配的前导树。由于对流脉冲的短暂特性,这种电荷结构可能在雷暴演变过程中以很短的间隔发生,这或许解释了与其他形式的大气放电相比,巨大喷流的稀有性。

雷暴电荷结构产生巨大喷流

图1:四种产生巨大喷流的雷暴的共同特征

摘要:Gigantic jets are atmospheric electrical discharges that propagate from the top of thunderclouds to the lower ionosphere. They begin as lightning leaders inside the thundercloud, and the thundercloud charge structure primarily determines if the leader is able to escape upward and form a gigantic jet. No observationally verified studies have been reported on the thundercloud charge structures of the parent storms of gigantic jets. Here we present meteorological observations and lightning simulation results to identify a probable thundercloud charge structure of those storms. The charge structure features a narrow upper charge region that forms near the end of an intense convective pulse. The convective pulse produces strong storm top divergence and turbulence, as indicated by large values of storm top radial velocity differentials and spectrum width. The simulations show the charge structure produces leader trees closely matching observations. This charge structure may occur at brief intervals during a thunderstorm’s evolution due to the brief nature of convective pulses, which may explain the rarity of gigantic jets compared to other forms of atmospheric electrical discharges.

阅读论文全文请访问:http://t.cn/E5c7XmZ

期刊介绍:Scientific Reports(https://www.nature.com/srep/) is an online, open access journal from the publishers of Nature. We publish scientifically valid primary research from all areas of the natural and clinical sciences.

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(来源:Scientific Reports)