Observation Results and Discussion on an Upward Leader Followed by a Long Continuing Current After a Return Stroke

Abstract

AbstractAn abnormal discharge process after a return stroke (RS) in a negative cloud‐to‐ground flash was studied in detail. Correlating high‐speed video images and electric field data, it was found that the abnormal discharge process was initiated at ground and transported positive charge from ground toward cloud. Moreover, there was a long continuing current (CC) initiated by the abnormal upward discharge process. Compared with the characteristics of RSs, CCs and M components, we conclude that the upward discharge process is a kind of upward positive leader. The 3‐D speeds of the positive leader range from 3.72 × 106 m/s to 14.48 × 106 m/s with average value of 6.5 × 106 m/s. As far as we know, it is the first report that a long CC follows the upward positive leader after RS, which is obviously different from traditional CCs. The discovery is helpful to gain a deeper understanding of the mechanism and physical process of negative cloud‐to‐ground flashes.