Side Discharges Involved in an Intracloud-Initiated Positive Cloud-to-Ground Lightning

Abstract:
Due to the weak radiation generated by positive leaders, our understanding of how positive leaders are initiated and reach the ground remains limited. This study investigated positive cloud-to-ground (CG) lightning induced after the long intra-cloud lightning based on high-speed video and fast antenna mapping results. Below the cloud base in the field of view, re-breakdowns of decayed negative branches occurred consecutively beneath the horizontal negative channel in the form of bidirectional leaders. These bidirectional leaders advanced along the same channel, and eventually, the third reached the ground, generating a positive return stroke (RS) with a peak current of 157 kA. After the RS, new side negative discharges occurred alongside the vertical return stroke channel, and they continued to propagate, forming a more than 200-ms-long continuing current (CC).