Multiple Strokes Along the Same Channel to Ground in Positive Lightning Produced by a Supercell
Yanan Zhu, Phillip M. Bitzer, Vladimir A. Rakov, Michael Stock, Jeff Lapierre, Elizabeth DiGangi, Ziqin Ding, Bruno L. Medina, Lawrence D. Carey, Timothy J. Lang
Abstract
Abstract Previous studies have shown that subsequent leaders in positive cloud‐to‐ground lightning (+CG) flashes rarely traverse pre‐existing channels to ground. In this paper, we present evidence that this actually can be common, at least for some thunderstorms. Observations of +CG flashes in a supercell storm in Argentina by Córdoba Argentina Marx Meter Array (CAMMA) are presented, in which 54 (64%) of 84 multiple‐stroke +CG flashes had subsequent leaders following a pre‐existing channel to ground. These subsequent positive leaders are found to behave similarly to their negative counterparts, including propagation speeds along pre‐existing channels with a median of 8 × 10 6 m/s, which is comparable to that of negative dart leaders. Two representative multiple‐stroke +CG flashes are presented and discussed in detail. The observations reported herein call for an update to the traditional explanation of the disparity between positive and negative lightning.