Simultaneous optical and electrical observations on the initial processes of altitude-triggered negative lightning

Lü, Weitao; Zhang, Yijun; Zhou, Xiuji; Qie, Xiushu; Zheng, Dong; Meng, Qingquan; Ma, Ming; Chen, Shaodong; Wang, Fei; Kong, Xiangzhen

doi:10.1016/j.atmosres.2008.01.011

Cited by 17 publications

(27 citation statements)

References 11 publications

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“…The overall development of the negative stepped leader presented here are consistent with observations of other negative stepped leaders in the initial stage of an altitude‐triggered flash [e.g., Laroche et al ., ; Lalande et al ., ; Chen et al ., ; Saba et al . ; Lu et al ., ]. Laroche et al .…”

Section: Discussionmentioning

confidence: 99%

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Negative leader step mechanisms observed in altitude triggered lightning

Biagi

Uman

Hill

et al. 2014

J. Geophys. Res. Atmos.

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We present 63 high-speed video frames (108 kilo-frames per second (kfps), 9.26 μs per frame) showing the development of the downward negative stepped leader in the initial stage of an altitude-triggered flash. The downward negative stepped leader initiated from the bottom of the triggering wire at a height of about 128 m above ground and, 553 μs later, it struck a lightning rod located at a distance of about 50 m from the launch tower. During the leader's development, electric field derivative pulses were detected associated with leader stepping. The interpulse intervals ranged from 3 to 27 μs with a mean value of 13 μs. Distinct segments of luminosity were observed ahead of the main leader channel that appear similar to space leaders were observed in the high-speed video frames. A total of eight luminous segments were observed that were 1 m to 6 m in length and were centered at distances from the main leader channel ranging from 3 m to 8 m. The new leader steps that appeared in the frames following the luminous segments were 5 m to 8 m in length. Two of the observed segments apparently never connected to the leader channel and thus failed to produce a new leader step.

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Section: Discussionmentioning

confidence: 99%

“…Lu et al . [] reported high‐speed video and electric field observations for an altitude trigger in August of 2005 at Binzhou, Shandong Province, China. The time intervals between steps ranged from 5 to 30 µs, and the mean time interval was 15 µs.…”

Section: Discussionmentioning

confidence: 99%

Negative leader step mechanisms observed in altitude triggered lightning

Biagi

Uman

Hill

et al. 2014

J. Geophys. Res. Atmos.

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“…Assuming that at these early times, the linear, fast‐rising portion of the optical waveform is dominated by the rapid geometric growth of the channel and that on average the channel is straight and vertical, then an estimate of the average luminous power per unit length (

ℓ_{o}

) that is emitted can be obtained from the following expression,

{scriptℓ}_{o} = \frac{4 π R^{2}}{v} \frac{italicdL}{italicdt}

where R is the distance to the stroke, v is the speed of propagation, and dL/dt is the measured slope of the irradiance, L, between T 1 and T 2 [ Guo and Krider , ]. In nature, each small segment of channel will actually radiate a luminosity that depends on how the current in that segment varies with time [ Jordan and Uman , ; Jordan et al ., ; Wang et al ., , , 1970; Chen et al ., ; Lu et al ., , ]; therefore, the values of

ℓ_{o}

actually represent a coarse spatial‐ and temporal‐average of the luminous power per unit length of channel at early times [ Guo and Krider , ]. The assumption that the channel is straight is likely to be valid only at the beginning of a return stroke when the bulk of the current is close to the ground, and at these early times, CG strokes will not usually have large branches.…”

Section: Datamentioning

confidence: 99%

“…The amplitudes and energies of lightning optical pulses are currently being used to detect and locate discharges from space [ Christian et al ., , ; Mach et al ., ; Hamlin et al ., ; Finke , ; Bankert et al ., ], and optical measurements have been used to estimate the power and energy dissipated by lightning [ Krider et al ., ; Hill , ; Guo and Krider , , ; Borucki and Chameides , ; Sisterson and Liaw , ; Paxton et al ., ; Borovsky , ]. Several previous ground‐based experiments have measured the irradiance from lightning strokes with fast time resolution [ Krider , ; Orville , ; Mackerras , ; Guo and Krider , , ; Jordan and Uman , ; Ganesh et al ., ; Orville and Henderson , ; Idone and Orville , ; Jordan et al ., , ; Chen et al ., ; Wang et al ., 1970; Lu et al ., ], and similar experiments have been performed on aircraft [ Christian et al ., ; Brook et al ., ; Christian and Goodman , ; Goodman et al ., ; Mach et al ., ] and on satellites [ Vorpahl et al ., 1970; Turman , , ; Orville , ; Christian et al ., ; Christian and Latham , ; Suszcynsky et al ., 2000, ; Kirkland et al ., ; Davis et al ., ; Boccippio et al ., ; Christian et al ., ; Noble et al ., ; Koshak , ; Jacobson et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Optical power and energy radiated by natural lightning

Quick

Krider

2013

JGR Atmospheres

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[1] Calibrated measurements of the visible and near-infrared radiation produced by both negative and positive cloud-to-ground (CG) lightning strokes have been made at distances of 5 to 32 km in southern Arizona (AZ) and the central Great Plains using a photodiode sensor with a flat spectral response between 0.4 and 1.0 mm. Time-correlated video images (60 fps) of the channel development provided information about the types of strokes that were detected and reports from the U.S. National Lightning Detection Network indicated their locations, polarities, and estimates of their peak current. In our sample of negative strokes that were suitable for analysis, there were 23 first (or only) strokes (FS), 19 subsequent strokes that created new ground contacts (NGC), and 101 subsequent strokes that re-illuminated a preexisting channel (PEC). We also analyzed 10 positive strokes (in nine flashes), and 73 of the larger impulses that were radiated by intracloud discharges (CPs). Assuming that these events can be approximated as isotropic sources and that the effects of atmospheric extinction are negligible, the peak optical power (P o ), total optical energy (E o ), and characteristic widths of the sources (t cw = E o /P o ) have been computed. Median values of P o for negative FS, NGC, and PEC strokes were 1.8 Â 10 10 W, 1.1 Â 10 10 W, and 4.4 Â 10 9 W, respectively. Median values of E o were 3.6 Â 10 6 J, 3.5 Â 10 6 J, and 1.2 Â 10 6 J, respectively. The median characteristic widths of negative FS, NGC, and PEC strokes were 229 ms, 244 ms, and 283 ms, respectively. Positive CG strokes produced a median P o , E o , and t cw of 1.9 Â 10 10 W, 9.3 Â 10 6 J, and 497 ms, respectively. Estimates of the space-and-time-average power per unit length (' o ) in the lower portion of negative FS, NGC, and PEC channels had medians of 2.8 Â 10 6 W/m, 3.2 Â 10 6 W/m, and 1.4 Â 10 6 W/m, respectively, and the median ' o for four positive strokes was 8.8 Â 10 6 W/m. Median values for the estimated peak electromagnetic power (P EM ) radiated at early times in the strokes are 2.0 Â 10 9 W, 2.5 Â 10 9 W, 1.0 Â 10 9 W, and 9.1 Â 10 9 W for FS, NGC, PEC and positive strokes, respectively. CP events produced a median P o , E o , and t cw of 2.0 Â 10 9 W, 0.7 Â 10 6 J, and 311 ms, respectively, and are in good agreement with aircraft and satellite measurements. The values of P o , E o , and ' o for negative CG strokes in AZ are significantly larger than prior measurements in Florida, likely because there is less atmospheric extinction in our dataset, and due to extinction, all the above values of P o , E o , and ' o are lower limits at the source.

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“…Large-amplitude bipolar current pulses are found to occur at the beginning of the upward negative leader pulse trains, and the corresponding electric field exhibits asymmetrical V-shaped pulses with a hump superimposed on the end of the pulse. The stepped leader characteristics in electric field waveforms at close range are similar to that of downward stepped leader pulses in altitude-triggered lightning flashes [7]. Distinct electric field changes prior to the upward negative leader inception are indicative of nearby lightning discharges.…”

Section: Instrumentation and Datamentioning

confidence: 56%

Simultaneous current and electric field observations of upward negative leaders initiated from the Gaisberg Tower

Zhou

Diendorfer

Thottappillil

et al. 2010

2010 Asia-Pacific International Symposium on Electromagnetic Compatibility

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In this paper, we present simultaneous current and electric field records of two upward negative leaders initiated from the Gaisberg Tower (GBT). It is shown that bipolar current pulses occur at the beginning of the upward negative leaders followed by regular unipolar leader pulse trains, and the corresponding electric field exhibits asymmetrical V-shaped pulses with a hump superimposed at the end of the pulse. The stepped leader characteristics in electric field waveforms at close range are similar to that of downward stepped leader pulses in altitude-triggered lightning flashes. Distinct electric field changes prior to the upward negative leader inception are indicative of nearby lightning discharges.

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Simultaneous optical and electrical observations on the initial processes of altitude-triggered negative lightning

Cited by 17 publications

References 11 publications

Negative leader step mechanisms observed in altitude triggered lightning

Negative leader step mechanisms observed in altitude triggered lightning

Optical power and energy radiated by natural lightning

Simultaneous current and electric field observations of upward negative leaders initiated from the Gaisberg Tower

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