This project will develop a field-deployable instrument system for characterizing lightning discharges in thunderstorms. Different U.S. research sites have an increasing need for such an instrument, and the system would bring together several techniques which have successfully been used to study lightning and thunderstorms. The system will determine the three-dimensional structure and development of lightning within a storm, both of individual lightning discharges and of the overall sequence of lightning activity. This is to be done using (1) a time-of-arrival (TOA) system for locating the sources of radio frequency radiation from the lightning discharges, revealing the structure and development of the lightning channels, and (2) time-resolved electric field change measurements, indicating the amounts of charge transfer along the channels, and therefore the strength of the discharge. Additional measurements of the atmospheric electrostatic field will characterize the overall electrical state of the parent thunderstorm.
