High‐Speed Video and Lightning Mapping Array Observations of In‐Cloud Lightning Leaders and an M Component to Ground

This is the authors' abstract. We don't add key points for this paper.

High‐speed video (46,000 frames per second) and lightning‐mapping‐array (LMA) data are correlated to determine three‐dimensional properties of in‐cloud lightning leaders (altitudes ranging from 2.78 to 3.81 km) observed in a rocket‐and‐wire triggered lightning flash. Three positive leaders were observed with speeds ranging from 6.1 × 10 4 to 1.0 × 10 5 m/s, one of which branched within the camera frame. The upper branch was then traversed twice by attempted negative leaders propagating toward the main channel to ground (speeds of 2.4 × 10 6 and 1.1 × 10 7 m/s). Both attempted negative leaders terminated abruptly at the branch point of the remnant channel. In the remnants of a separate positive leader channel, a bidirectional leader initiated, which resulted in an M component whose luminosity and current were measured at ground. Analysis shows that the luminosity wave associated with the entire M component process (propagating 8.8 km from initiation to ground) is highly dispersive, with calculated group velocities ranging from 1 × 10 7 to 5 × 10 7 m/s over the dominant signal bandwidth of DC (0 Hz) to 2 kHz.