Orientation of Initial Breakdown Pulses and Leader Discharges by Magnetic Direction Finder

Lü, Zhigang; Qiu, Shi; Wang, Ruichao; Shi, Lihua; Zhang, Peng

doi:10.1029/2019jd031407

Cited by 6 publications

(5 citation statements)

References 30 publications

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“…A magnetic antenna which contained two crossed orthogonal rectangle coils oriented in EW and NS direction was also deployed. The output of each coil was connected to an integrating amplifier circuit, with the −3 dB bandwidth of 3 kHz to 2 MHz (Lu et al, 2020). In Site B, a traditional broadband interferometer system consisting of three VHF antennas was deployed, operated in sequence recording mode.…”

Section: Observation and Datamentioning

confidence: 99%

Broadband VHF Observations of Two Natural Positive Cloud‐to‐Ground Lightning Flashes

Qiu

Shi

et al. 2020

Geophysical Research Letters

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The characteristics of two natural positive cloud‐to‐ground flashes are analyzed in detail with the broadband very high frequency (VHF) mapping system. The bidirectional leader processes at the lightning initiation are observed, with negative leaders propagating upward and positive leaders propagating downward. The downward positive leaders can be divided into two stages, with scattered and slowly extending sources in the first stage and more concentrated and faster sources in the second stage. The overall extension speeds of the first stages are 1.8 × 104 and 2.7 × 104 m/s for the two flashes, and the speeds of the second stages are 7.8 × 105 and 1.0 × 106 m/s, respectively. The received peak power of the positive leaders is substantially lower than that for the negative leaders. The frequency characteristics show that the second stage emits more high‐frequency radiation than the first stage, while there is no significant difference in low‐frequency radiation content.

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Section: Observation and Datamentioning

confidence: 99%

Broadband VHF Observations of Two Natural Positive Cloud‐to‐Ground Lightning Flashes

Qiu

Shi

et al. 2020

Geophysical Research Letters

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“…It is mainly used to find the azimuth angle of the return stroke in CG lightning. MDF systems are implemented using a vertical magnetic loop or cross-loop antenna [33], [34]. The MDF technique requires at least two sensors to determine the location of a lightning strike.…”

Section: Magnetic Direction Findermentioning

confidence: 99%

Lightning Mapping: Techniques, Challenges, and Opportunities

et al. 2020

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Despite the significant progress in the understanding of the phenomenon of lightning and the physics behind it, locating and mapping its occurrence remain a challenge. Such localization and mapping of very high frequency (VHF) lightning radiation sources provide a foundation for the subsequent research on predicting lightning, saving lives, and protecting valuable assets. A major technical challenge in attempting to map the sources of lightning is mapping accuracy. The three common electromagnetic radio frequencybased lightning locating techniques are magnetic direction finder, time of arrival, and interferometer (ITF). Understanding these approaches requires critically reviewing previous attempts. The performance and reliability of each method are evaluated on the basis of the mapping accuracy obtained from lightning data from different sources. In this work, we review various methods for lightning mapping. We study the approaches, describe their techniques, analyze their merits and demerits, classify them, and derive few opportunities for further research. We find that the ITF system is the most effective method and that its performance may be improved further. One approach is to improve how lightning signals are preprocessed and how noise is filtered. Signal processing can also be utilized to improve mapping accuracy by introducing methods such as wavelet transform in place of conventional cross-correlation approaches. INDEX TERMS interferometer, lightning mapping, magnetic direction finder, time of arrival.

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“…It is mainly used to find the azimuth angle of return stroke in CG lightning. The MDF systems are implemented by using a vertical magnetic loop or cross-loop antenna [29,30]. The MDF technique requires at least two sensors to determine the lightning strike location.…”

Section: Magnetic Direction Findermentioning

confidence: 99%

Lightning Mapping: Techniques, Challenges, and Opportunities

Alammari¹,

Alkahtani²,

Ahmad³

et al. 2020

Preprint

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Despite the significant progress made in studying the lightning phenomenon, precise location and mapping of its occurrence remain a challenge. Lightning mapping can be determined by studying the electromagnetic radiation accompanying the lightning discharges. It can contribute substantially to efforts made to protect lives and valuable assets. There are three main methods used to locate lightning, which are Magnetic Direction Finder (MDF), Time of Arrival (TOA), and Interferometer (ITF). A thorough study of these methods provides researchers with a guide to better understand and progress in this field. This paper reviews existing approaches used to locate and map lightning within these three methods. We study the implemented techniques, analyze their merits and demerits, and sort them in a way that facilitates extracting opportunities for further improvements. We conclude that for better development in determining the location and map of lightning, improving the processing of lightning signals and filtering the associated noise with it is essential. This includes introducing new processing methods such as wavelet transformation instead of the traditional cross-correlation. The use of artificial intelligence may also contribute a lot, particularly deep learning, to determining the type of lightning, which enables better mapping for the lightning and its occurrence. We also could conclude that unlike MDF and TOA, which can locate the lightning strike points, ITF can produce lightning discharge propagation images that can unveil the mechanism of lightning discharges. Finally, this paper serves as a reference for researchers focusing on lightning mapping to give them insight into the field.

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Orientation of Initial Breakdown Pulses and Leader Discharges by Magnetic Direction Finder

Cited by 6 publications

References 30 publications

Broadband VHF Observations of Two Natural Positive Cloud‐to‐Ground Lightning Flashes

Broadband VHF Observations of Two Natural Positive Cloud‐to‐Ground Lightning Flashes

Lightning Mapping: Techniques, Challenges, and Opportunities

Lightning Mapping: Techniques, Challenges, and Opportunities

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