Research of Atmospheric Electric Field Characteristics in the Process of Lightning in Time and Frequency Domain

This paper takes four typical lightning occur in Chengdu area as the research objects, analyzing the atmospheric electric field that before, during and after the lightning in time domain and frequency domain, selecting 30 minutes as the research time. It found that the volatility and amplitude of electric field intensity and the electric field gradient with time in local is small before the lightning occurs, larger and obvious during lightning occurs, decreasing after the lightning. Through the analysis of the energy, it found that the electric field energy is greater before lightning, the largest during lightning occurs, and reduced after the lightning in frequency domain. With the approach of the lightning, in frequency domain, the amplitude and energy of the electric field increases gradually, in the same time, curves fluctuate more obviously. Set the lightning warning level in time domain and frequency domain respectively and forecast lightning in Chengdu area as this standard, for further validating the effect on early warning system for lightning. The Ts score above 70%, missing report rate to zero, false alarm rate below 25%, which shows that these two warning levels can be effective to forecast near lightning warning.