| 一次多回击触发闪电全过程的连续干涉仪观测 |
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| 引用本文： | 张阳,陈泽方,王敬轩,樊艳峰,郑栋,吕伟涛,张义军.一次多回击触发闪电全过程的连续干涉仪观测[J].应用气象学报,2020,31(2):197-212. |
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| 作者姓名： | 张阳 陈泽方 王敬轩 樊艳峰 郑栋 吕伟涛 张义军 |
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| 作者单位： | 1.中国气象科学研究院灾害天气国家重点实验室/雷电物理和防护工程实验室, 北京 100081 |
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| 摘 要： | 基于自主研发的闪电连续干涉仪，对2019年6月11日在中国气象局雷电野外科学试验基地广州从化人工引雷试验场成功触发的一次多回击闪电放电全过程进行观测，结合通道底部电流数据和电场变化数据，共同揭示触发闪电全放电过程:连续干涉仪能够定位到最小为8 A的不连续的先驱电流脉冲辐射信号，初始先驱电流脉冲(IPCP)的平均转移电荷量约为先驱电流脉冲(PCP)的2倍；上行正先导连续发展后为初始连续电流(ICC)过程，最初正流光通道以105 m·s-1量级的速度继续发展延伸，之后出现反冲先导放电；在ICC阶段出现的经典M分量，可由向前的106 m·s-1量级速度的正流光(先导)产生，也可由已有通道头部产生的反冲先导产生，且整个M分量过程中，多个反冲先导维持了放电过程的持续；之后的回击间过程以反冲先导为主要放电形式，回击电流脉冲之前存在多次反冲先导过程，但多数未发展到接地通道，只处于企图先导阶段，直至成功的先导回击产生；而前两次回击具有超短的时间间隔，约为4.5 ms，这是由于两次回击前的先导来源于云内不同分支的反冲先导过程。
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| 关 键 词： | 触发闪电 全放电过程 连续干涉仪 多回击 |
| 收稿时间： | 2019-10-08 |
Observation of the Whole Discharge Process During a Multi-stroke Triggered Lightning by Continuous Interferometer |
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| Affiliation: | 1.Laboratory of Lightning Physics and Protection Engineering/State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 1000812.Department of Atmospheric and Oceanic Sciences & Institute of Atmospheric Sciences, Fudan University, Shanghai 200438 |
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| Abstract: | The discharge process is often discussed in the lightning physics. VHF (very high frequency) observations play an important role in studying lightning discharge processes, because they show where air breakdown occurs. Triggered lightning flashes are ideal research objects, because they are generated in a fixed time and place. Regular experiments of triggering lightning have been conducted by Chinese Academy of Meteorological Sciences since 2006, and 189 lightning flashes are triggered successfully. Besides regular observations, such as fast/slow antenna, channel-based current and high-speed video, the continuous interferometer (CINTF) is developed and deployed at the site for triggered lightning after 2016 in order to observe detailed discharge processes. The CINTF can provide high-precision location with time resolution of around 1 μs.A multi-stroke triggered lightning with 8 return strokes is observed by a self-developed lightning continuous interferometer during Guangdong Comprehensive Observation Experiment on Lightning Discharge on 11 June 2019. The whole discharge processes, including precursor current pulse, initial precursor current pulse, initial continuous current and return strokes, last for about 1600 ms. The channel-based current, electric field change and radiation source positions are obtained. CINTF results show that the radiation signal generated from discrete precursor current pulse with a minimum value of about 8 A can be detected. The average transfer charge of initial precursor current pulse is twice as much as that of the precursor current pulse. During the initial continuous current stage after continuously developing of the upward positive leader, the obviously forward channel extension is the main discharge form at the beginning, and then the extension can be accompanied by discontinuously backward propagation, and recoil leader often occurs in the following stage. M-component in the ICC stage is caused by two discharge processes:Forward positive streamer (or leader) or recoil leader generated in the existing channel. Multi recoil leaders occur during the whole M process, which maintain M discharge. The main discharge form in return stroke stage is recoiling discharge. There are multi recoil leaders before return strokes, however, most of them cannot develop to ground, keep as an attempted leader until the last leader-stroke occurs. Adjacent two strokes with a short duration time of 4.5 ms have the same optical channel in optical images, but they are obviously different in development paths, which lead to a very short RS interval. |
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