We have examined an unusual rocket-triggered lightning flash during the summer campaign of the SHAndong Triggered Lightning Experiment(SHATLE)in 2018.High-speed video camera observations and three-dimensional(3D)light...We have examined an unusual rocket-triggered lightning flash during the summer campaign of the SHAndong Triggered Lightning Experiment(SHATLE)in 2018.High-speed video camera observations and three-dimensional(3D)lightning mapping show that the upward positive leader split into two branched channels(referred to as branch A&branch B,respectively)at a height of about 370 m,and then progressed into different charge regions of the thundercloud.Branch A initially developed upward before turning northwest from the trigger point;ten pronounced intermittent negative leaders were observed propagating downward along this branch channel,causing strong current pulses.Branch B propagated obliquely upward towards the northeast before continuing northward to a region of weak radar echo at 3 km altitude,resulting in a large-scale charge transfer of approximately–250 C(C=Coulomb)and generating a sustained,strong current exceeding 2 kA.Furthermore,downward dart leaders propagating along branch A connected to the active channel of branch B at the bifurcation point.This connection generated a surge of large current pulses(M-components)superimposed on the continuing current.Evidence from 3D lightning mapping and concurrent channel-base current measurements suggests that the 10th negative dart leader split during its downward propagation,with one branch propagating to ground,while the other entered into a positive charge reservoir.This initiated a positive charge transfer to ground via the existing channel,ultimately triggering the final stroke which exhibited a bi-polarity current pulse.展开更多
基金supported by National Key R&D Program of China(2023YFC3007703,2017YFC1501501)the CAS Project of Stable Support for Youth Team in Basic Research Field(YSBR-018)+2 种基金National Natural Science Foundation of China(41875006,and U1938115)Youth Innovation Fund Project of the University(WK2080000172)the Chinese Meridian Project.
文摘We have examined an unusual rocket-triggered lightning flash during the summer campaign of the SHAndong Triggered Lightning Experiment(SHATLE)in 2018.High-speed video camera observations and three-dimensional(3D)lightning mapping show that the upward positive leader split into two branched channels(referred to as branch A&branch B,respectively)at a height of about 370 m,and then progressed into different charge regions of the thundercloud.Branch A initially developed upward before turning northwest from the trigger point;ten pronounced intermittent negative leaders were observed propagating downward along this branch channel,causing strong current pulses.Branch B propagated obliquely upward towards the northeast before continuing northward to a region of weak radar echo at 3 km altitude,resulting in a large-scale charge transfer of approximately–250 C(C=Coulomb)and generating a sustained,strong current exceeding 2 kA.Furthermore,downward dart leaders propagating along branch A connected to the active channel of branch B at the bifurcation point.This connection generated a surge of large current pulses(M-components)superimposed on the continuing current.Evidence from 3D lightning mapping and concurrent channel-base current measurements suggests that the 10th negative dart leader split during its downward propagation,with one branch propagating to ground,while the other entered into a positive charge reservoir.This initiated a positive charge transfer to ground via the existing channel,ultimately triggering the final stroke which exhibited a bi-polarity current pulse.
