Return stroke current during Shandong artificially triggered lightning from 2005–2009

Shandong artificial triggering lightning experiment (SHATLE) by means of rocket-wire technique, aimed to understand the close electromagnetic environment of lightning channel and its correlation to the discharge current, was started at 2005 in Binzhou, Shandong. Artificially triggered lightning is thought to be similar to the subsequent return strokes in natural lightning. Sixty seven negative return strokes were successfully triggered from 2005 to 2009. The discharge current at the base of the discharge channel and electromagnetic fields at different distances were measured simultaneously for 25 return strokes. Although the data is not enough, the distribution of peak current of the triggered strokes shows a probability of lognormal distribution. The geometric mean value was about 11.8 kA with a minimum of 5.8 kA and a maximum of 45.7 kA. The geometric mean of the 10-90% rise time was 1.9 μs, the geometric mean of the half peak width was 22.5 μs and the geometric mean of the charge transfer within 1 ms of return strokes was 0.7 C.