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DOI	10.1016/j.atmosres.2019.04.013
	Initial electric field changes of lightning flashes in tropical thunderstorms and their relationship to the lightning initiation mechanism
	Sabri M.H.M.; Ahmad M.R.; Esa M.R.M.; Periannan D.; Lu G.; Zhang H.; Cooray V.; Williams E.; Aziz M.Z.A.A.; Abdul-Malek Z.; Alkahtani A.A.; Kadir M.Z.A.A.B.
发表日期	2019
ISSN	0169-8095
起始页码	138
结束页码	151
卷号	226
英文摘要	In this paper, the key finding is that all the examined first classic Initial Breakdown (IB) pulses in tropical flashes within the reversal distance were found to be initiated by a clearly detectable Initial E-field Change or IEC (45 –CG, 32 normal IC, and 3 IC initiated by +NBE). The durations of IECs for both –CG and IC flashes in tropical storms were longer than in Florida storms. On the other hand, for the magnitudes of the E-change, the values were smaller compared to Florida storms with averages of 0.30 V/m compared to 1.65 V/m for –CG flashes, and −0.81 V/m compared to −6.30 V/m for IC flashes. The IEC process of lightning flashes in tropical regions took longer to increase the local electric field in order to produce the first IB pulse because of the smaller magnitude of E-change. On the other hand, in Florida storms, the IEC process took a shorter time to increase the local electric field to produce the first IB pulse because of the larger magnitude of E-change. We found that very high frequency (VHF) pulses for tropical thunderstorms started sometime prior to the onset of the IECs. They started between 12.69 and 251.60 μs before the initiation of the IEC for two normal IC flashes. The first two VHF pulses were detected alone without narrow IB pulses (fast antenna and slow antenna records) or any pulses from the B-field and dE/dt records. Furthermore, the VHF pulses for three IC flashes initiated by +NBEs were also detected before the onset of the IEC. The IEC started immediately after the detection of the +NBE. It is clear that the IEC is initiated by VHF pulses. It can be suggested that lightning is initiated by Fast Positive Breakdowns or FPBs (which emit strong VHF pulses and large +NBEs) and is followed by several negative breakdowns (weak VHF pulses and/or weak NBE-type pulses) before the IEC started. For the case of normal IC flashes, several weaker VHF pulses (mean values of 41.97 mV and 46.4 mV compared to the amplitudes of the VHF pulses of +NBEs of around 800 mV) were detected before the onset of the IEC. As FPBs can occur with a wide range of VHF strengths and E-change amplitudes, it can be suggested these weak VHF pulses accompanied by narrow IB pulses or weak NBE-type pulses detected before the onset of IEC are actually FPBs followed by negative breakdowns or several attempted FPBs. © 2019 Elsevier B.V.
英文关键词	Fast positive breakdown; Initial breakdown pulse; Initial electric field changes; Narrow bipolar event; Negative breakdown
语种	英语
scopus关键词	Antennas; Lightning; Thunderstorms; Tropics; Electric field change; Fast positive breakdown; Initial breakdown pulse; Narrow bipolar events; Negative breakdown; Electric fields; amplitude; electric field; lightning; thunderstorm; Florida [United States]; United States
来源期刊	Atmospheric Research
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/162208
作者单位	Atmospheric and Lightning Research Laboratory, Centre for Telecommunication Research and Innovation (CeTRI), Fakulti Kejuruteraan Elektronik dan Kejuruteraan Komputer, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, Durian Tunggal, Melaka 76100, Malaysia; Institute of High Voltage and High Current (IVAT), Universiti Teknologi Malaysia (UTM), Skudai, Johor Bharu 81310, Malaysia; Key Laboratory of Middle Atmosphere and Global Environment Observation, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, 100029, China; Ångström Laboratory, Division for Electricity, Department of Engineering Sciences, Uppsala University, Box 534S-75121, Sweden; Massachusetts Institute of Technology (MIT), Cambridge, MA 02139-4307, United States; Universiti Tenaga Nasional (UNITEN), Jalan IKRAM-UNITEN, Kajang, Selangor 43000, Malaysia
推荐引用方式 GB/T 7714	Sabri M.H.M.,Ahmad M.R.,Esa M.R.M.,et al. Initial electric field changes of lightning flashes in tropical thunderstorms and their relationship to the lightning initiation mechanism[J],2019,226.
APA	Sabri M.H.M..,Ahmad M.R..,Esa M.R.M..,Periannan D..,Lu G..,...&Kadir M.Z.A.A.B..(2019).Initial electric field changes of lightning flashes in tropical thunderstorms and their relationship to the lightning initiation mechanism.Atmospheric Research,226.
MLA	Sabri M.H.M.,et al."Initial electric field changes of lightning flashes in tropical thunderstorms and their relationship to the lightning initiation mechanism".Atmospheric Research 226(2019).