Initial stage in lightning initiated from tall objects and in rocket‐triggered lightning

Abstract

[1] We examine the characteristics of the initial stage (IS) in object-initiated lightning derived from current measurements on the Gaisberg tower (100 m, Austria), the Peissenberg tower (160 m, Germany), and the Fukui chimney (200 m, Japan) and their counterparts in rocket-triggered lightning in Florida. All lightning events analyzed here effectively transported negative charge to ground. For rocket-triggered lightning the geometric mean (GM) values of the three overall characteristics of the initial stage, duration, charge transfer, and average current, are similar to their counterparts for the Gaisberg tower flashes and the Peissenberg tower flashes, while the Fukui chimney flashes are characterized by a shorter GM IS duration and a larger average current. The GM IS charge transfer for the Fukui chimney flashes is similar to that in the other three data sets.The GM values of the action integral differ considerably among the four data sets, with the Fukui action integral being the largest. The observed differences in the IS duration between the Fukui data set and all other data considered here are probably related to the differences in the lower current limits, while the differences in the action integral cannot be explained by the instrumental effects only. There appear to be two types of initial stage in upward lightning. The first type exhibits pulsations (ringing) during the initial portion of the IS, and the second type does not. The occurrence of these types of IS appears to depend on geographical location. The characteristics of pulses superimposed on the initial continuous current (ICC pulses) in object-initiated (Gaisberg, Peissenberg, and Fukui) lightning are similar within a factor of 2 but differ more significantly from their counterparts in rocket-triggered lightning. Specifically, the ICC pulses in object-initiated lightning exhibit larger peaks, shorter risetimes, and shorter half-peak widths than do the ICC pulses in rocket-triggered lightning.

Geometrical and electrical characteristics of the initial stage in Florida triggered lightning

“…The UPL/ICC for flash UF 11-32 was of unusually long duration (about 945 ms) and charge transfer (about 225 C), about three times the duration and about eight times the charge transfer of the typical values reported by Wang et al [1999] (GM duration of 279 ms and GM charge transfer of 27 C) and Miki et al [2005] (GM duration of 305 ms and GM charge transfer of 30.4 C) for triggered lightning discharges at the ICLRT.…”

Influence of the lightning triggering rocket wire and its corona on the electric field at ground level

“…The decrease of the electric field at ground level, at a given distance from the wire and for a given conductor radius r representing the wire with its corona sheath, can be expressed as (3) in which Eo is the background electric field, and Ez(h = 300 m) is the vertical electric field determined when the rocket reaches a height of300 m above ground. Fig.…”

“…Lightning discharges triggered by small rockets trailing a thin wire are widely used in lightning research [1,2] since there are many similarities between triggered lightning and subsequent strokes in natural lightning [3] . In addition, the triggered lightning technique allows the simultaneous measurement of various lightning parameters.…”

Self-initiated and other-triggered positive upward lightning measured at the Peissenberg Tower, Germany

“…The leader produces a slow-varying initial continuous current (ICC) (e.g. see [1]), which typically lasts some tens to some hundreds of milliseconds and has the magnitude up to some thousands of amperes. For a positive upward lightning, the polarity of the upward leader is negative due to the transfer of positive charge from the leader to ground.…”