Abstract:
Multi-station observation on lightning flashes in the Chinese Inland Plateau area was conducted in the summer of 2004 by using fast electric file change, slow electric file change and field mill. The high time-resolution GPS (its absolute timing accuracy was 50 ns) was used to synchronize the signals from each station. Based on the data obtained from multi-station lightning observations, characteristics of the lightning activities in the thunderstorms and pulses in the lightning flashes were analyzed. By using the technique of differential time of arrival (DTOA), a lightning radiation location technique, based on the fast electric field changes, was developed. Radiation pulses in the initial stages of five intracloud (IC) lightning discharges which occurred on Aug 20, 2004 were located with the developed technique. The results indicate that the location technique could effectively locate the lightning radiation sources. The lightning sources were found to be nicely associated with the storm activity. When the storm was at mature stage, with echo top of 9 km, the lightning sources were located from 3.3 to 6.4 km above ground; when the storm gradually became weak, with echo top of 6 km, the lightning sources were located from 1.1 to 4.0 km. Especially, one of IC lightning discharges were located from 1.1 to 3.0 km during the weaken stage of the storm. Compared with the Doppler radar echo, the location of the radiation sources were found to be nicely associated with the high reflectively storm regional, and the echo intensity was between 25 dBz and 50 dBz. It is not only conformed the reliability of the location results to some extent but also showed that the fast electric filed change detection system can be used to monitor the overall storm development with the height and rate of the sources. In addition, the results and the location error were also analyzed with the Doppler radar data and the simulated location results. The results show that the location error is small when the radiation sources near the detect net, and the error increases steadily for more distant sources. It is found that the modeled result can effectively reflect the location errors by compared with the limited experimental observations.