Relation between lightning return stroke peak current and following continuing current

The magnitude of the return stroke peak current preceding continuing current ( CC) in ground flashes was investigated. This study was performed using a high-speed camera ( 1,000 frames/s), an electric field flat-plate antenna and data provided by the Brazilian Lightning Detection Network (RINDAT). The observation of 454 negative strokes followed by CC with durations from 4 ms to 542 ms revealed that negative strokes combining both peak current greater than 20 kA and CC greater than 40 ms are highly unlikely to occur. However, this was found to be possible for positive strokes. In addition, we found that on average the longer the CC, the lower the return stroke peak current preceding it. Therefore, the average detection efficiency of RINDAT was found to decrease from 62% for negative strokes followed by very-short CC ( less than 10 ms) to 36% for strokes followed by long CC, with an intermediate value of 57% for strokes followed by short ( from 10 to 40 ms) CC.