Miki M., Shindo T., Rakov V.A., Uman M.A., Rambo K.J., Schnetzer G.H., Diendorfer G., Mair M., Heidler F., Zischank W., Thottappillil R., Wang D.:
Characterization of the initial stage of upward-initiated lightning
International Conference on Lightning Protection (ICLP), Cracow, Poland, 2002
We compare the characteristics of the initial stage (IS) in natural upward lightning as observed on (1) the Gaisberg tower (100 m, Austria), (2) the Peissenberg tower (160 m, Germany), and (3) the Fukui chimney (200 m, Japan) with their counterparts in rocket-triggered lightning in Florida. All current records in Japan and some of the current records in Germany and Austria were obtained in winter, whereas all triggered-lightning data were obtained in summer. All lightning events analyzed here effectively transported negative charge to ground. The geometric mean (GM) values of the overall characteristics of the IS, duration (T), charge transfer (Q), and average current (I), for rocket-triggered lightning (T = 305 ms, Q = 30.4 C, I = 99.6 A) are similar to their counterparts for Gaisberg-tower flashes (T = 235 ms, Q = 29.6 C, I = 126 A) and Peissenberg-tower flashes (T = 290 ms, Q = 38.5 C, I = 133 A), while the Fukui-chimney flashes are characterized by a somewhat shorter GM initial-stage duration (T = 77.1 ms) and a larger average current (I = 505 A). The GM initial stage charge transfer for the Fukui-chimney flashes is 38.9 C. The observed differences in the IS duration is probably related to the difference in the lower current measurement limits: about 200 A for the Fukui data set vs. 15 to 20 A for the other three data sets. The characteristics of the initial continuous current (ICC) pulses in object-initiated (Gaisberg, Peissenberg, and Fukui) lightning are similar within a factor of two to three, but differ more significantly from their counterparts in rocket-triggered lightning. Specifically, the ICC pulses in object-initiated lightning exhibit larger peaks, shorter rise times, and shorter half-peak widths than do the ICC pulses in rocket-triggered lightning.
PDF File (522 KB)