Winter lightning on Japan Sea coast-development of measuring system on progressing feature of lightning discharge

A Critical Review of Nonconventional Approaches to Lightning Protection

“…This value of leader speed is arbitrary, since it is not supported by experimental data, as discussed next. The only existing measurements of upward positive leader speeds in natural lightning are due to McEachron (1939), Berger andVogelsanger (1966, 1969), and Yokoyama et al (1990). McEachron (1939) reported that upward positive leaders initiated from the Empire State Building propagated at speeds ranging from 5.2 x 10 4 to 6.4 x 10 5 m s _1 , with the lengths of individual leader steps ranging from 6.2 to 23 m. Berger andVogelsanger (1966, 1969) measured speeds between 4 x 10 4 and about 10 6 m s _1 for seven upward positive leaders, with the individual leader step lengths ranging from 4 to 40 m. Further, for four of the seven leaders Berger and Vogelsanger (1966) measured speeds ranging from 4 to 7.5 x 10 4 m s _1 and step lengths from 4 to 8 m at altitudes ranging from 40 to 110 m from the tower top, where a connection between a downward leader and an upward-connecting leader would be expected.…”

“…McEachron (1939) reported that upward positive leaders initiated from the Empire State Building propagated at speeds ranging from 5.2 x 10 4 to 6.4 x 10 5 m s _1 , with the lengths of individual leader steps ranging from 6.2 to 23 m. Berger andVogelsanger (1966, 1969) measured speeds between 4 x 10 4 and about 10 6 m s _1 for seven upward positive leaders, with the individual leader step lengths ranging from 4 to 40 m. Further, for four of the seven leaders Berger and Vogelsanger (1966) measured speeds ranging from 4 to 7.5 x 10 4 m s _1 and step lengths from 4 to 8 m at altitudes ranging from 40 to 110 m from the tower top, where a connection between a downward leader and an upward-connecting leader would be expected. Yokoyama et al (1990) measured, for three cases, upward leader speeds between 0.8 to 2.7 x 10 5 m s _1 . They show figures in which the stepping of both the upward and downward leader is apparent.…”

Attachment of lightning flashes to grounded structures

“…This is partly due to the several experiments conducted at instrumented tall towers [44,61,[80][81][82][83][84][85][86] and to the use of rocket triggered lightning techniques [74][75][76], and partly due to the improvement in theoretical leader inception and propagation models [54][55][56][57][58][59]. From the experimental perspective, different experiments with natural and triggering lightning have provided valuable information about the physical properties of upward and downward leaders under natural conditions.…”

“…The first measurements of upward connecting leaders (under the influence of downward stepped leaders) reported in the literature appeared in 1990 [80]. The average propagation velocity of the observed upward connecting leaders initiated from a tall tower ranged from 8 × 10 4 to 2.7 × 10 5 m s -1 .…”

“…The average propagation velocity of the observed upward connecting leaders initiated from a tall tower ranged from 8 × 10 4 to 2.7 × 10 5 m s -1 . Unfortunately, it is not possible to distinguish between positive or negative upward connecting leaders in the dataset reported in [80] since neither the polarity nor the return stroke peak current were reported. Recently, the propagation of an upward connecting leader initiated from a tower under the influence of a branched descending stepped leader has been detected with an intensified, high-speed camera in the USA [84].…”