FORTE radio-frequency observations of lightning strokes detected by the National Lightning Detection Network

• Published in: Journal of Geophysical Research 2000-06, Vol.105 (D12), p.15
• Main Authors: Jacobson, Abram R, Cummins, Kenneth L, Carter, Michael, Klinger, Philip, Roussel-Dupre, Diane, Knox, Stephen O
• Format: Article
• Language: English
• ISSN: 0148-0227

This work compares simultaneous observations of lightning from two complementary systems: FORTE, an LEO satellite whose radio receivers observe VHF emissions from the air breakdown process preceding a lightning current, and the National Lightning Detection Network (NLDN), a ground-based sensor array which observes LF and VLF radiation from vertical currents. We have found that there is a statistically significant correlation, for a subset of FORTE events. This correlation is most likely to occur for intracloud and less likely to occur for cloud-to-ground discharges. The correlated VHF and NLDN events tend to occur within +/- 30 microsec of each other, after correction for the propagation of the VHF signal to FORTE from the NLDN-geolocated stroke location. Most correlations outside of +/- 30 microsec turn out to be merely a statistical accident. The NLDN-furnished geolocation allows the correlated FORTE-detected VHF pulses to be better interpreted. In particular, we can deduce, from the lag of the VHF ground-reflection echo, the height of the VHF emission region in the storm. (Author)