Compact intracloud discharges: New classification of field waveforms and identification by lightning locating systems
Compact intracloud discharges: New classification of field waveforms and identification by lightning locating systems
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DOI：
10.1016/j.epsr.2019.04.016
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发表时间：
2019-08
影响因子：
3.9
通讯作者：
A. Leal;V. Rakov;B. Rocha
中科院分区：
文献类型：
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作者：
A. Leal;V. Rakov;B. Rocha
我们分析了1022个紧凑的云内放电（CID）的宽带电场波形，这些放电向上传输负电荷，并在2016年由佛罗里达盖恩斯维尔（Gainesville）闪电观测站的闪电探测和波形存储系统（LDWSS）记录。根据NLDN，所有检查的事件都发生在距赤道500公里的范围内。CID是地球上最强的HF-VHF辐射的自然产生者，可能对空中交通工具构成严重威胁。利用其在时域波形和频谱上的特征，将其与其他闪电过程区分开来。共发现了11种CID电场波形，其中7种以前没有单独报道过。观察到的CID中有一半以上在其双极电场波形的相反极性过冲上显示出明显的振铃，这表明存在反弹波过程。两个主要的闪电定位系统（NLDN和ENTLN）都将我们的大部分CID报告为CG（基本上都是+CG）。高强度事件的CID错误分类百分比较高：对于0-20 kA、20-50 kA和≥ 50 kA的峰值电流范围，NLDN分别错误分类了10%、97%和100%的CID。ENTLN的相应百分比为2%、63%和100%。
We analyzed wideband electric field waveforms of 1022 compact intracloud discharges (CIDs) that transported negative charge upward and were recorded in 2016 by the Lightning Detection and Waveform Storage System (LDWSS) operating at the Lightning Observatory in Gainesville (LOG), Florida. According to the NLDN, all the examined events occurred within 500 km of the LOG. CIDs, which are the strongest natural producers of HF-VHF radiation on Earth may represent a serious threat to airborne vehicles. They were distinguished from other lightning processes using their characteristic features in both the time-domain waveform and the frequency spectrum. Eleven types of CID electric field waveshapes were identified, seven of which have not been reported as separate types before. More than half of the observed CIDs showed pronounced ringing on the opposite-polarity overshoot of their bipolar electric field waveforms, which is indicative of a bouncing wave process. Two major lightning locating systems (NLDN and ENTLN) each reported most of our CIDs as CGs (essentially all as+ CGs). The percentage of misclassified CIDs was higher for higher-intensity events: for peak current ranges of 0–20 kA, 20–50 kA, and≥ 50 kA NLDN misclassified 10%, 97%, and 100% of CIDs, respectively. The corresponding percentages for ENTLN were 2%, 63%, and 100%.