[1] A study of cloud-to-ground lightning characteristics based on high-speed camera observations of 455 flashes related to 40 thunderstorms is presented. The Brazilian Lightning Location Network (RINDAT) was used to calculate the polarity and the distance of the flashes to the camera. In some cases, a fast electric field flat antenna was also used to calculate the time difference between strokes on a microsecond-scale. Some general features of the data set are briefly presented. This paper is focused on two specific characteristics observed in video records with a frame a rate of 1,000 frames/s: (i) six strokes presenting two ground terminations that were simultaneously connected for some milliseconds, (ii) and a high number of continuing current occurrences with durations less than 10 ms.

/pdf/high-speed-camera-observations-of-negative-ground-flashes-on-2nti4slc4j.pdf

High-speed camera observations of negative ground flashes on a millisecond-scale

Characteristics of triggered lightning during Shandong artificial triggering lightning experiment (SHATLE)

[1] We have analyzed very high frequency lightning mapping observations and remote magnetic field measurements to investigate connections between lightning morphology and impulse charge moment change (iCMC) of negative cloud-to-ground (CG) strokes with high estimated peak currents. Four lightning morphologies are identified for a total of 2126 strokes within optimum detection range of the North Alabama Lightning Mapping Array, and statistical iCMC distributions are given for each of these types. Almost all (>90%) of the largest impulse charge moments (greater than −200 C km in this data set) are not produced by strokes in ordinary negative CG flashes. Instead, negative strokes with the largest iCMCs are almost exclusively associated with two unusual flash types that both initially develop as positive (normal) intracloud lightning. In the first type the negative stroke with high iCMCs results from a negative leader that descends from the midlevel negative charge region after the upper level negative leader ceases propagating. In the second type, the upper level negative leader of the intracloud lightning progresses toward ground as a so-called bolt from the blue to generate the negative stroke. Measurements of strokes associated with four negative polarity sprites suggest that all four were most likely produced in the first unusual lightning type. Our results highlight that estimated peak current and impulse charge transfer are not always well correlated and that the in-cloud lightning structure strongly influences charge transfer on short time scales in negative CG strokes.

/pdf/lightning-morphology-and-impulse-charge-moment-change-of-2v3f4r9wgh.pdf

Lightning morphology and impulse charge moment change of high peak current negative strokes

Electrical characteristics of thunderstorms in different plateau regions of China

http://www.lzb.cas.cn/kyjz/201405/P020140521403075395555.pdf

Electrical structure of a Qinghai–Tibet Plateau thunderstorm based on three-dimensional lightning mapping

The possible charge structure of thunderstorm and lightning discharges in northeastern verge of Qinghai Tibetan Plateau

Optical and electrical characteristics of in-cloud discharge activity and downward leaders in positive cloud-to-ground lightning flashes

During the summers of 2012 and 2013, field observations of lightning processes were conducted to investigate the characteristics of lightning discharges over a Chinese inland plateau. A total of 17 cloud-to-ground (CG) flashes were recorded by a high-speed video camera in 7 thunderstorm systems. Seven of the CG flashes had two or more contacts: 6 were multiple-channel flashes (MCFs) and 1 was a flash with multiple-ground-termination-stroke (MGTS). The percentage of CG flashes with multiple contacts was approximately 41% in Pingliang. The highest number of termination MCFs was three. The average percentage of such flashes recorded by the same camera in different regions of China was approximately 22%, ranging from 12% to 41%. The IC process before the return stroke occurred between the lower positive charge region and the middle negative charge region of the thunderstorm. Based on the optical images of the long-duration IC activity before the first stroke, it seems that the negative CG flashes can be initiated by a branch of a cloud flash or produced by a cloud flash.

http://or.nsfc.gov.cn/bitstream/00001903-5/406523/1/1000009011846.pdf

Research on natural cloud-to-ground lightning flashes over a chinese inland plateau

For the large positive charge region under the thundercloud base, we conducted the experiments during the summer of 2012 and 2013 in Pingliang, Gansu province, China, to invest the characteristics of lightning processes. The characteristics of CG flash have been analyzed based on both the images from high-speed video camera and electric field changes from fast and slow antennas. The luminescence of the leader which contacted with the ground was weaker than that of flash in other region of China. In the CG lightning flashes, four out of them had more than one contact on the ground and the most was three. The luminescence time of leader lasted time were about 3-25 ms. And the most return stroke order was nine.

http://www.nssl.noaa.gov/users/mansell/icae2014/preprints/Kong_136.pdf

Huaibin Wang

Papers

The possible charge structure of thunderstorm and lightning discharges in northeastern verge of Qinghai Tibetan Plateau

Optical and electrical characteristics of in-cloud discharge activity and downward leaders in positive cloud-to-ground lightning flashes

Research on natural cloud-to-ground lightning flashes over a chinese inland plateau

The Optical Characteristics of Cloud-to-ground Lightning Flashes in Pingliang of China ∗