1991 Volume 111 Issue 1 Pages 93-98
Characteristics of lightning flashes with multiple strikes to the ground within 1s are investigated, based on the data of video pictures of lightning channels and the electric field changes. In winter, the occurrence frequency of lightning flashs with multiple strikes to the ground is 55% which is roughly twice as large as that in summer. The number of strike points in winter is also larger than that in summer. The largest number of strike points is 17 in winter, whereas 4 in summer. The polyphase fault on a power transmission line in winter might be caused by a lightning flash of this type. The average time intervals between strokes are less than 17 ms (one TV field) in winter and 90ms in summer respectively. The average distance between strike points are 1.3km in winter and 1.9km in summer.