Use of passive radar for mapping lightning channels in a thunderstorm

Researchers at the Severe Storms Research Center (SSRC), Georgia Institute of Technology are attempting to detect tornado formation within severe thunderstorms occurring within the vicinity of Atlanta, Georgia using Doppler radar and non-radar sensors that may provide early tornado warning. The goal of these studies is to increase the warning time of tornado formation within the parent thunderstorm. Currently, GTRI researchers use real time S-band Doppler weather radar data from three National Weather Service (NWS) WSR 88D NEXRAD radars displayed on a work station developed and optimized for tornado detection by the National Severe Storms Laboratory (NSSL). Three NWS radars provide severe weather surveillance coverage of the north Georgia area to determine if a thunderstorm contains the Doppler signature that indicates tornado formation. There is also the capability to display cloud to ground (CG) lightning strikes provided by a national monitoring network. The symbology indicating CG strike location is imposed on the radar reflectivity map. GTRI also uses a local lightning direction finder (DF) system that supplies azimuth and range to the lightning strike. This paper discusses the early lightning channel research and the passive parasitic radar system being operated by the SSRC. Lightning detection tests are also presented.