Speed and current for lightning stepped leaders near ground as determined from electric field records

摘要: The speed and current during the final stages of lightning stepped leader were determined from features electric field waveform. average tip was found below height where dE/dt zero for close lightning. This in range 0.6–2.0 km flashes at distances considered here, 3.6–5.7 km. For 10 leaders observed near Tampa, Florida, mean one-dimensional 4.4×105 m/s, standard deviation 3.8×105 1.0–14×105 m/s. These speeds are consistent with other reported literature that using optical techniques. estimated when ground last hundred microseconds before return stroke. 62 3.6–14 km, 1.3 kA, 1.0 geometric 110 A to 5.0 kA. Errors resulting uncertainties distance, charge center height, calibration, channel inclination, branching be about 40–50% rms both current.