抄録
Electric filed changes due to lightning discharges are analyzed by means of Wavelet. Since the electric field changes are the non-stationary phenomena, the conventional Fast Fourier Transform (FFT) Analysis is not sufficient to investigate the transition of electric field spectra as functions of time. The main objective of this paper is to discuss the feasibility of the forecasting of lightning to the ground to consult the transition of electric fields. For this purpose the typical electric field changes of the positive cloud to ground strokes, which were observed during winter thuderstorms, are analyzed. The transition of spectra corresponding to the preliminary breakdown pulses, return strokes and continuing currents with pulses are shown and the feasibility of forecasting is suggested.
