Characteristics of lightning echoes observed with VHF ST radar
Article first published online: 7 DEC 2012
Copyright 1995 by the American Geophysical Union.
Volume 30, Issue 4, pages 1085–1097, July-August 1995
How to Cite
1995), Characteristics of lightning echoes observed with VHF ST radar, Radio Sci., 30(4), 1085–1097, doi:10.1029/95RS00648., , , and (
- Issue published online: 7 DEC 2012
- Article first published online: 7 DEC 2012
- Manuscript Accepted: 6 DEC 1994
- Manuscript Received: 1 JUN 1994
The development of tropospheric convection was observed with the Chung-Li VHF stratosphere-troposphere (ST) radar in Taiwan, Republic of China. Deep convection evolved into thunderstorms during which radar echoes from lightning were recorded with a particular high time resolution program. These lightning echoes usually exist for only several tens to a few hundred milliseconds. To investigate the fine structure in the amplitude and phase of the lightning returns, the necessary time resolution has to be in the order of a few milliseconds. Such time resolutions are for the first time applied with VHF ST radar and the initial results are presented in this paper. Rapid jumps in the phase path were occurring together with sudden amplitude changes. This indicates that the scattering regions change their position, which could be on different branches of the lightning stroke. Large radial velocities of the lightning scattering regions up to several tens of meters per second were observed. Also, strong velocity shears were noticed in these lightning echo regions. Power peaks in Doppler spectra corresponding to velocities of about 300 m s−1 were occasionally detected. It is contemplated that these are caused by Bragg scattering from sound waves resulting from the lightning shock wave. Also a periodic velocity and amplitude modulation of a thin sheet of radar reflectivity was observed which one could attribute to infra-sound with a frequency of about 6–7 Hz. Preliminary conclusions are drawn finally to confirm that our observations are generally consistent with backscatter from lightning.