Abstract
Three-dimensional imaging of lightning channels by means of UHF interferometers is performed. To realize this, a field campaign was conducted with two observation sites in Darwin Australia. The distance between two sites is about 14km, and the triangulation scheme is applied to estimate locations of UHF radiation sources. Since the UHF radiation during the leader progression is more expected than the return stroke phase, imaging of lightning channels is obtained mainly for the downward leaders. Velocities of downward leaders are estimated and statistics are shown for first and subsequent strokes. The result is consistent with those of former investigators obtained by optical observations. The statistics for the velocity of leader propagation inside thunderclouds is shown in this paper. By using optical measurement, velocity estimation of leader progressions inside thundercloud is impossible, and presented results is concluded to be the first results.
