It is the first time, by using a high-speed camera system with the rate of 2000 frames per second (fps), that the optical evidences of the initiation processes of altitude-triggered negative lightning (ATNL) are observed with complete time series. The initiation contains several processes, I.e., the inception and propagation of the upward positive leader (UPL), the bi-directional leader process which contains the simultaneous propagation of UPL and downward negative leader (DNL), “mini-return stroke” (MRS), and the upward discharge from the bottom of the triggering wire after MRS, etc. Combined with the observation of electric field change with 0.2 μ s time resolution, those processes are analyzed in detail.
展开▼
