A Strong Positive CG Flash That Was Simultaneously Recorded by Multiple Observation Systems

We have documented a super positive lightning flash with DALMA (Discone Antenna Lightning Mapping Array), FALMA (Fast Antenna Lightning Mapping Array), InLMA (Interferometer-type of Lightning Mapping Array) as well as LAPOS (Lightning Attachment Process Observation System) and a high speed video camera. Using the documented data, we found this positive flash started with a downward negative leader from an upper negative charge region. The initial negative leader progressed into the lower positive charge region at an average speed of 1.0$\times 10^{6}$ m/s and then was followed by many discharge activities in this region. These discharge activities consequently pumped positive charge to the negative leader initiation region and then produced a downward positive leader with a speed of 1.6× 106 m/s. This positive leader, accompanied by two steps, produced a positive return stroke with its peak current reaching to 268 kA. After the return stroke, a lot of discharge activities occurred between the upper negative charge and the lower positive charge regions. We estimated that the total electrical charge neutralized by this flash was over 1000 C. We also measured the speeds for the two step pulse discharges and the return stroke and found their speeds are 0.8$\times10^{8} m/s, 0.82$× 108 m/s, and 1.15×108 m/s, respectively.