18
th International Lightning Detection Conference (ILDC), Helsinki, Finland, 2004
201 lightning flashes with a total of 1015 strokes were recorded at the Gaisberg tower from January 2000 to September 2002. From these 201 recorded flashes 62 (31%) did not show any impulse current superimposed on or following the initial continuing current (ICC) being typical for upward initiated lighting.
From the remaining 139 events showing pronounced current pulses, 129 flashes were classified as upward discharges, 10 as downward flashes. This classification is based on the measured lightning channel current prior to the first stroke current pulse. Unfortunately video images showing the direction of channel branching are not available for many events due to bad visibility. The classification from the current flow only may be questionable in some cases.
In the presentation we will show cumulative frequency distributions for the different lightning current parameters as total charge (see Fig) and impulse charge (Q), peak current (Ip), specific energy (W/R) and current steepness (di/dt). The statistical analysis is done separately for the so called a -pulses (superimposed on the ICC) and ß-pulses (following a period of no current in the lightning channel).
In the contribution we will also discuss the differences and similarities to published current parameters measured at other elevated objects as the CN tower or the Peissenberg tower.
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