文摘
Abstract
Shandong artificial triggering lightning experiment (SHATLE) has been continuously conducted at Binzhou, Shandong since the summer of 2005. Eight negative lightning flashes including 32 return strokes were successfully triggered from 2005 to 2007 during the passage of 5 mesoscale convective systems. The discharge current at the base of the discharge channel and close electromagnetic fields at 60 m and 550 m distance were measured simultaneously. The whole discharge process of the triggered lightning flashes lasted from 518 ms to 1900 ms. Two intense return strokes with peak currents of 41.6 kA and 38.0 kA were observed in two classical triggered flashes. The range of current peak value for 14 recorded strokes in 3 triggered flashes varied from 6.6 kA to 41.6 kA with an average value of 17.6 kA. The half peak width of the current waveform ranged from 0.9 to 47.0 µs with an average value of 30.7 µs. The electric field changes produced by the dart leader/return stroke sequences appeared as V-shape pulses, and the distance dependence of the dart leader electric field change was r− 1.18.
