Analysis of Lightning Current Above the Strike Point of Side Flash to the Canton Tower

Abstract Characteristics of lightning current approximately 40 m above the strike point of side flashes to the 454‐m high observation deck of the Canton Tower were investigated for the first time. Observations show that the lightning current waveforms exhibited a bipolar feature with a primary positive peak followed by a negative one during the return‐stroke phase. The amplitudes of the peaks range from approximately 2 to 4 kA. The interval between the two peaks is approximately equal to the round‐trip time for the lightning current traveling from the strike point to the ground. The comprehensive analysis results of observation and numerical simulation indicate that lightning current injected into the strike point of side flashes to a tall object will diverge into two components, which propagate upward and downward, respectively, leading to partial lightning current wave traverse the part located above the strike point.