抄録
In this paper, the characteristics of the positive lightning flashes in the coastal area of the Sea of Japan and the lightning stroke model for the estimation of an upward lightning current waveform were described based on observation results. The positive lightning flashes initiated upward from a radio tower were observed in winter 2001. The current peak value and the electric charge of the lightning flashes were much larger than those of summer lightning flashes. Slow front and fast transition, which are common characteristics of the electric field waveform associated with all the return strokes, were not recognized clearly at the rising portion of the lightning waveform. The calculated waveform using the lightning stroke model for the upward lightning, in which the current wave propagates downward from the cloud and reflects at the ground, agreed well with the observed waveform.
