Characterization of Multitermination CG Flashes Using a 3D Lightning Mapping System (FALMA)

Gao, Panliang; Wang, Daohong; Shi, Dongdong; Wu, Ting; Takagi, Nobuyuki

doi:10.3390/atmos10100625

Cited by 4 publications

(5 citation statements)

References 19 publications

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“…It is interesting to note that distances between RSs in MS +CG flashes are generally larger than those between RSs creating new terminations in −CG flashes (Gao et al, 2019; Thottappillil et al, 1992). The difference is probably due to different origination mechanisms of leaders for subsequent strokes in +CG and −CG flashes.…”

Section: Resultsmentioning

confidence: 99%

“…As will be discussed in section 4, most subsequent strokes in +CG flashes are likely initiated by positive leaders originating from in‐cloud negative leader channels, so the distance between sequential positive strokes is approximately the distance traveled by a negative leader during the interstroke interval. On the other hand, subsequent RSs in −CG flashes are produced by recoil leaders propagating backward from positive leader channels to the initiation location and then deflecting from the previous main channel during the downward propagation (Gao et al, 2019; Stolzenburg et al, 2019). As a result, new terminations are usually very close to old terminations in −CG flashes.…”

Section: Resultsmentioning

confidence: 99%

“…This result indicates that first strokes in MS +CG flashes are usually much stronger than subsequent strokes. Similarly, first strokes in −CG flashes are also usually stronger than subsequent strokes, even when subsequent strokes create new terminations (Gao et al, 2019; Rakov & Uman, 1990).…”

Section: Resultsmentioning

confidence: 99%

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Multiple‐Stroke Positive Cloud‐to‐Ground Lightning Observed by the FALMA in Winter Thunderstorms in Japan

Wang

Takagi

2020

JGR Atmospheres

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Multiple-stroke (MS) positive cloud-to-ground (+CG) lightning flashes are rarely reported, especially those with high-quality location information. In this study, we report 47 MS +CG flashes observed in winter thunderstorms in Japan with a 14-site fast antenna lightning mapping array (FALMA). MS +CG flashes account for 18% of +CG flashes. The mean multiplicity of all +CG flashes is 1.24, and the maximum multiplicity is 5. Interstroke intervals have a very large range from 1.0 to 1,320.6 ms with the geometric mean of 64.4 ms. In three flashes, interstroke intervals smaller than 2 ms are observed, and corresponding positive strokes are inferred to be produced by two branches of the same positive leader. Horizontal distances between sequential positive strokes range from 1.1 to 37.3 km with the geometric mean of 9.7 km. No subsequent strokes struck at the same location as a previous stroke. Distances between sequential strokes are generally much larger than distances between first strokes and lightning initiation locations. Subsequent stroke peak amplitudes are on average 0.45 of first stroke peak amplitudes. In 39 flashes (83%), the first stroke is stronger than the largest subsequent stroke in the same flash. Subsequent stroke amplitudes are weakly correlated with the time difference from the previous stroke. Origination mechanisms of positive leaders initiating first and subsequent positive strokes are discussed. It is very likely that positive leaders for most subsequent strokes originate from in-cloud negative leader channels, but origination mechanisms for positive leaders initiating first strokes are more varied.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Multiple‐Stroke Positive Cloud‐to‐Ground Lightning Observed by the FALMA in Winter Thunderstorms in Japan

Wang

Takagi

2020

JGR Atmospheres

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“…Stolzenburg et al () labeled this group of subsequent stepped leaders as the “branch mode‐early leader” inception type. In a related study, Gao et al () studied 205 CG flashes with multiple ground strike locations (which implies the existence of one or more subsequent stepped leaders) and found that the average flash initiation height was 5.8‐km altitude, while the average “leader fork height” for the subsequent stepped leader was 4.7 km.…”

Section: Discussionmentioning

confidence: 99%

On the Transition From Initial Leader to Stepped Leader in Negative Cloud‐to‐Ground Lightning

2020

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High‐speed video and electric field change data are used to describe the first 5 ms of a negative cloud‐to‐ground flash. These observations reveal an evolution in character of the luminosity and electric field change pulses as two branches of the leader separately transition from initial leader to propagating as a negative stepped leader (SL). For the first time reported, there is evidence of weak luminosity coincident with the initiating event, a weak bipolar pulse 60 μs prior to the first initial breakdown (IB) pulse. During the IB stage, the initial leader advances intermittently at intervals of 100–280 μs, in separate light bursts that are bright for a few 20‐μs frames and are time coincident with IB pulses. In the intervals between IB pulses, the initial leader is dim or invisible during the earliest 1.8 ms. Within 2 ms, the leader propagation begins transitioning to an early SL phase, in which the leader tip advances at more regular intervals of 40–80 μs during relatively dim and brief steps which are coincident with SL pulses having short duration, small amplitude, and typically unipolar waveform. These data indicate that when the entire initial leader length behind the lower end begins to remain illuminated between bursts, the propagation mode changes from IB bursts to SL steps, and the IB stage ends. The results support a hypothesis that the early initial leader development occurs in the absence of a continuously hot channel, thus the initial leader propagation is physically unlike the self‐propagating SL advance.

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“…As shown in [17], using FALMA, a detailed 3D mapping for lightning flashes occurring inside the network can be produced. The estimated horizontal location accuracy for RSs was around 20 m. More information about FALMA and the results obtained in Japan with FALMA can be found in [19][20][21][22][23][24].…”

Section: Configuration Of Ningxia Falmamentioning

confidence: 89%

Initial Results of Long-term Continuous Observation of Lightning Discharges by FALMA in Chinese Inland Plateau Region

Gao

Wang

2021

Atmosphere

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We started a long-term continuous observation of lightning discharges in the Chinese inland plateau region using a fast antenna lightning mapping array (FALMA). During the first year of observation, 2019, we recorded lightning discharges on 25 days in Yinchuan city, the capital of Ningxia. Most of the lightning discharges appeared to occur in the afternoons of individual thunderstorm days in August. We studied the cloud-to-ground (CG) flash percentages, lightning discharge source spatiotemporal distributions, and preliminary breakdown (PB) process characteristics for the two thunderstorm cases that produced the most frequent lightning flashes in 2019 over a wide area. It was found that (1) CG flashes in these two thunderstorms accounted for 28.4% and 32.5% of total lightning flashes, respectively; (2) most lightning discharge sources in these two thunderstorms occurred at temperatures between 5 and −30 °C, with a peak at around −10 °C; and (3) more than 90% of well-mapped PB processes of intracloud (IC) flashes propagated downward. By overlapping the altitudes and the progression directions of the PB processes on the lightning source spatiotemporal distributions, we inferred that the main negative charge of the two storms observed in Ningxia, China, was at a height of around −15 to −25 °C (7 to 9 km) and the main positive charge was at a height of around 5 to 0 °C (2 to 4 km).

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Characterization of Multitermination CG Flashes Using a 3D Lightning Mapping System (FALMA)

Cited by 4 publications

References 19 publications

Multiple‐Stroke Positive Cloud‐to‐Ground Lightning Observed by the FALMA in Winter Thunderstorms in Japan

Multiple‐Stroke Positive Cloud‐to‐Ground Lightning Observed by the FALMA in Winter Thunderstorms in Japan

On the Transition From Initial Leader to Stepped Leader in Negative Cloud‐to‐Ground Lightning

Initial Results of Long-term Continuous Observation of Lightning Discharges by FALMA in Chinese Inland Plateau Region

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