Upward lightning flashes characteristics from high‐speed videos

Saba, Marcelo M. F.; Schumann, Carina; Warner, Tom A.; Ferro, Marco; Paiva, Amanda R. de; Helsdon, John H.; Orville, Richard E.

doi:10.1002/2016jd025137

Cited by 47 publications

(62 citation statements)

References 27 publications

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“…The taller the object, the greater the chances that it will initiate upward lightning. Saba et al (2016) found that all the 100 upward flashes they studied in Brazil and in the United States were triggered by other discharges, in contrast to the observation in Austria (Diendorfer et al, 2018) that 80% of the 307 upward flashes from the Gaisberg Tower were self-initiated. Wang et al (2008) classified upward lightning into self-initiated and other-triggered flashes, depending on whether or not there was nearby lightning activity immediately preceding the initiation of an upward leader.…”

Section: Introductionmentioning

confidence: 68%

“…While most of cloud-to-ground lightning flashes are initiated by downward leaders, initiation by a leader propagating upward from the grounded object to the overhead thundercloud is also possible. The proportion of self-initiated and other-triggered lightning flashes apparently depends on storm type, its stage of development, and other factors and varies significantly in different studies (e.g., Diendorfer et al, 2018;Heidler et al, 2014;Jiang et al, 2014;Saba et al, 2016;Smorgonskiy et al, 2015;Takagi & Wang, 2011;Warner, Cummins, & Orville, 2012;Zhou et al, 2012). Berger and Vogelsanger (1969) suggested that the high electric field needed for the initiation of upward lightning is rapidly created by an in-cloud discharge, rather than being a consequence of the slower charge buildup in the cloud produced by the cloud electrification processes.…”

Section: Introductionmentioning

confidence: 99%

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Evolution of an Upward Negative Lightning Flash Triggered by a Distant +CG From a 257‐m‐Tall Tower, Including Initiation of Subsequent Strokes

Zhu

Ding

Rakov

et al. 2019

Geophysical Research Letters

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Using the high‐speed optical and electric field records, in conjunction with Earth Networks Total Lightning Network and radar data, we examined in detail the morphology and evolution of an upward negative flash containing six downward leader/upward return stroke sequences terminated on a 257‐m tower in Florida. The upward flash was induced (triggered) by a single‐stroke 50‐kA +CG that occurred about 45 km from the tower. The in‐cloud part of +CG was optically detected to extend toward the tower and appeared to stop at a height of about 3 km above the tower top. The six leader‐return‐stroke sequences were each initiated by a bidirectional leader utilizing the remnants of branches created during the initial stage. Electric field signatures of bidirectional leaders were similar to K‐changes. The upper end of the return‐stroke channel in all six cases exhibited branching and appeared to extend to higher altitudes or/and move closer to Lightning Observatory in Gainesville with increasing stroke order.

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Section: Introductionmentioning

confidence: 68%

Section: Introductionmentioning

confidence: 99%

Evolution of an Upward Negative Lightning Flash Triggered by a Distant +CG From a 257‐m‐Tall Tower, Including Initiation of Subsequent Strokes

Zhu

Ding

Rakov

et al. 2019

Geophysical Research Letters

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“…In fact, all of the above flashes (F1–F4) are other‐triggered upward flashes [ Wang et al , ; Saba et al , ]. Such flashes are initiated by a rapid electric field change caused by other nearby lightning flashes, so it is an expected result that they do not have any relationship with corona discharges.…”

Section: Resultsmentioning

confidence: 92%

Corona discharges from a windmill and its lightning protection tower in winter thunderstorms

Wang

Rison

et al. 2017

JGR Atmospheres

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This paper presents lightning mapping array (LMA) observations of corona discharges from a windmill and its lightning protection tower in winter thunderstorms in Japan. Corona discharges from the windmill, called windmill coronas, and those from the tower, called tower coronas, are distinctly different. Windmill coronas occur with periodic bursts, generally radiate larger power, and possibly develop to higher altitudes than tower coronas do. A strong negative electric field is necessary for the frequent production of tower coronas but is not apparently related with windmill coronas. These differences are due to the periodic rotation of the windmill and the moving blades which can escape space charges produced by corona discharges and sustain a large local electric field. The production period of windmill coronas is related with the rotation period of the windmill. Surprisingly, for one rotation of the windmill, only two out of the three blades produce detectable discharges and source powers of discharges from these two blades are different. The reason for this phenomenon is still unclear. For tower coronas, the source rate can get very high only when there is a strong negative electric field, and the source power can get very high only when the source rate is very low. The relationship between corona discharges and lightning flashes is investigated. There is no direct evidence that corona discharges can increase the chance of upward leader initiation, but nearby lightning flashes can increase the source rate of corona discharges right after the flashes. The peak of the source height distribution of corona discharges is about 100 m higher than the top of the windmill and the top of the tower. Possible reasons for this result are discussed.

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“…Continuing current (CC) is defined as the relatively low‐level current lasting for tens to hundreds of milliseconds that immediately follows a return stroke (RS) in both natural flashes (Kitagawa et al, ; Rakov & Uman, ) and triggered flashes (W. Lu et al, ; Saba et al, ). In order to distinguish from CC, the term initial continuous current is used, which follows an upward positive leader that occurred before a RS in the initial stage in both rocket‐triggered (Fisher et al, ; G. Lu et al, ) and object‐initiated lightning (Flache et al, ; Miki et al, ).…”

Section: Introductionmentioning

confidence: 99%

Observation Results and Discussion on an Upward Leader Followed by a Long Continuing Current After a Return Stroke

Shi

Qiu

et al. 2018

Geophysical Research Letters

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An abnormal discharge process after a return stroke (RS) in a negative cloud‐to‐ground flash was studied in detail. Correlating high‐speed video images and electric field data, it was found that the abnormal discharge process was initiated at ground and transported positive charge from ground toward cloud. Moreover, there was a long continuing current (CC) initiated by the abnormal upward discharge process. Compared with the characteristics of RSs, CCs and M components, we conclude that the upward discharge process is a kind of upward positive leader. The 3‐D speeds of the positive leader range from 3.72 × 106 m/s to 14.48 × 106 m/s with average value of 6.5 × 106 m/s. As far as we know, it is the first report that a long CC follows the upward positive leader after RS, which is obviously different from traditional CCs. The discovery is helpful to gain a deeper understanding of the mechanism and physical process of negative cloud‐to‐ground flashes.

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Upward lightning flashes characteristics from high‐speed videos

Cited by 47 publications

References 27 publications

Evolution of an Upward Negative Lightning Flash Triggered by a Distant +CG From a 257‐m‐Tall Tower, Including Initiation of Subsequent Strokes

Evolution of an Upward Negative Lightning Flash Triggered by a Distant +CG From a 257‐m‐Tall Tower, Including Initiation of Subsequent Strokes

Corona discharges from a windmill and its lightning protection tower in winter thunderstorms

Observation Results and Discussion on an Upward Leader Followed by a Long Continuing Current After a Return Stroke

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