Leader Polarity‐Reversal Feature and Charge Structure of Three Upward Bipolar Lightning Flashes

Shi, Dongdong; Wang, Daohong; Wu, Ting; Thomas, Ronald J.; Edens, H. E.; Rison, W.; Takagi, Nobuyuki; Krehbiel, P. R.

doi:10.1029/2018jd028637

Cited by 15 publications

(27 citation statements)

References 17 publications

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“…The high ratio of PCG lightning (100% for 12 November, 81% for 14 November, 38% for 2 December, and 66% for all three cases) and great positive peak current (medians of 39 kA for 12 November, 59 kA for 14 November, 78 kA for 2 December, and 67 kA for all three cases) and relatively frequent bipolar lightning (a total of three bipolar CG flashes) agreed with previous studies on the lightning characteristics in winter thunderstorms (Goto & Narita, 1995;Ishii & Saito, 2009;Narita et al, 1989;Shi et al, 2018;Suzuki, 1992;Takeuti et al, 1976;Wang et al, 2008). Compared with the LMA flashes (Table 1), the thunderstorm on 12 November had the lowest ratio of CG lightning (~6%), followed by 2 December (~32%), and 14 November (~52%).…”

Section: Cg Flash Datasupporting

confidence: 90%

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Charge Regions Indicated by LMA Lightning Flashes in Hokuriku's Winter Thunderstorms

et al. 2019

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The charge distribution of some cells in three winter thunderstorms in the Hokuriku region of Japan is investigated based on Lightning Mapping Array (LMA) flash data. The vertical arrangements of charge regions involved in lightning discharges suggest diverse charge patterns, including quad‐polar, tripole, positive dipole, inverted dipole, and inverted tripole. The riming electrification between graupel and ice crystals or their aggregations are thought to be responsible for the electrification of most cells. The charging process between snow/aggregates and ice crystals may be responsible for some inverted charge structure that occurred above 0 °C isotherm and accompanied with weak radar echoes. Convection indicated by the vertical development of radar reflectivity appears crucial to shaping the diverse charge distribution patterns by determining which charging mechanisms occur and where; it also influences changes in height or even the disappearance of the charge regions. The charged cores are distributed from 0.7‐ to 5.3‐km heights and 2‐ to –31‐ °C temperatures, while the distances between adjacent charged cores with opposite polarities change between 0.2 and 3.4 km, with a mean of 1.3 km. The mean flash duration and horizontal distance are 425.0 ms and 19.8 km, respectively. The average height, temperature, and power of flash initiations are 2.8 km, −11.9 °C, and 15.6 dBW, respectively.

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Section: Cg Flash Datasupporting

confidence: 90%

“…Its base current was measured; therefore, the polarities of the leaders were tested by investigating the synchronous recordings of the current and LMA sources. Shi et al () analyzed this flash and the current measurements in their study on the polarity reversal feature of the leader in upward bipolar lightning.…”

Section: Methodsmentioning

confidence: 99%

Charge Regions Indicated by LMA Lightning Flashes in Hokuriku's Winter Thunderstorms

et al. 2019

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“…Prior to the positive return stroke, there must be a positive leader propagating down to the ground. Although LMA did not detect the positive leader leading to the positive return stroke, likely due to the masking effect of the on‐going negative leader, we believe that the positive leader was formed from a defunct branch of the negative leader through a leader‐polarity reversal mechanism [23,24]. The return stroke of the flash in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…3. If a PCG flash initiated above the main positive charge, a negative leader will first propagate in the positive charge region and then transform into a positive leader to the ground producing a positive return stroke through a leader polarity reversal mechanism [23,24]. The later the leader polarity reversal occurs, the smaller the positive charge left for the positive leader due to the longer neutralization by the negative leader, consequently a smaller return stroke will be produced, and vice versa.…”

Section: Discussionmentioning

confidence: 99%

Winter Positive Cloud‐to‐Ground Lightning Flashes Observed by LMA in Japan

Wang

Zheng

et al. 2021

IEEJ Transactions Elec Engng

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Using a lightning mapping array (LMA), we have observed 24 positive cloud‐to‐ground (CG) flashes occurred in three thunderstorm days. These flashes can be apparently grouped into 5 clusters according to their occurrence times. We have obtained the charge structures for both the individual flashes and clusters. It was found that 4 out of 5 clusters of positive CG flashes exhibited either inverter dipolar or tri‐polar charge structures. This result indicates that the high percentage of positive CG flashes in Hokuriku winter thunderstorms originated from the inverted charge structure rather than the various deformations of normal charge structures widely accepted in literatures. The flash positive charge appeared to distribute usually in a layer with its thickness of around 1 km, its horizontal area of more than 100 km2 and its bottom altitude of around 1–2 km above the ground. For each of the flash, we have also obtained its duration, length, duration before the first stroke and convex area. It was found that all flashes with a large peak return stroke current had short durations before their first return strokes. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

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“…An alternative mechanism to explain the positive leader developing from the negative leader channel is similar to the polarity reversal mechanism proposed by Wang and Takagi (2008) and Shi et al (2018). Suppose a branch of the negative leader, which is not well resolved by the location results, becomes defunct while the main channel keeps propagating forward, positive charges from the head of the main channel may be transferred back to the defunct branch.…”

Section: 1029/2020jd033039mentioning

confidence: 85%

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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Leader Polarity‐Reversal Feature and Charge Structure of Three Upward Bipolar Lightning Flashes

Cited by 15 publications

References 17 publications

Charge Regions Indicated by LMA Lightning Flashes in Hokuriku's Winter Thunderstorms

Charge Regions Indicated by LMA Lightning Flashes in Hokuriku's Winter Thunderstorms

Winter Positive Cloud‐to‐Ground Lightning Flashes Observed by LMA in Japan

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

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