Bead and Rocket Lightning

[摘要] Three photographs of lightning flashes were taken on the evening of Aug. 20, 1924 at about 7 o'clock by Mr. T. Takayama, my assistant, at the Central Meteorological Observatory, Tokyo. Two of them are shown in Pl. 1. The camera with film was left open until the moment when a lightning fiash was seen, then it was closed and the film was changed with a new one and then again the camera was open. Thus seven films were exposed, of which only three had the picture of flashes which are none of the ordinary fork or zigzag lightning, but are something of the nature of bead and rocket lightnings discharging into air. In fig. a or Pl. 12, 4 groups and in fig. b 3 groups of lightning flashes of nearly the same height are shown. In the other photograph (omitted) one group is seen very near the horizon. Each group of flashes consists of luminous spots and branching line-flashes. The following points perhaps are worth mentioning. (1.) The photographs were taken facing towards the north and the thunder clouds were then shifting to the east. The luminous spots, circular in the photographs perhaps were actually sphericel, assemble in western part of each group and those in the eastern part have line lightnings starting from them. (2) The luminous spots are mostly arranged along some curved lines (invisille), which lie mainly in east-west direction with more or less inclination. (3) There are various sizes of spots. (4) Most of the spots are circular; only 2 out of nearly 100 are elongated a little in the east-west direction (See fig. b, the central group, central part) (5) The line lightnings are not those. bridging one electric polo to the other, but they are radiating from same _??_mmon center into air. (6) They have always spot lights at their feet. The line lighnings bave pin shape, lecoming gradually slender, ending at last at shatp _??_nds. (8) The terminal parts of the line lightnings have a tendency to curve towards the east. (9) The biggest line lightning of each group extends. always toward the most approximate east and smaller ones are gradually distributed upeard and downward in the order of magnitude. (10) The line lightnings have branches. which have no spot light at their feet. (11) Some of the line lightnings have zigzag outline as if they were bracteated. (12) In the central part of each groups diffused light is seen.Many hypotheses may be formed to explain the above phenomana, but they cannot be conchusive. Only the conclusion that we can draw is that the so called bead and rccket lightnings are real. phenomena having objective existence.

[学科分类] 大气科学