Terrestrial gamma ray flashes and lightning discharges

Abstract

Analysis of ELF/VLF broadband data from Palmer Station, Antarctica indicates that 76% Terrestrial Gamma‐ray Flashes (TGFs) detected on the RHESSI spacecraft occur in association with lightning‐generated radio atmospherics arriving from near the footprint of RHESSI and within a few ms of the TGF. The remaining TGFs are not associated with any radio atmospheric, thus by implication CG lightning. The peak currents of TGF‐associated lightning discharges are often among the most intense from a given storm, with the degree of this association apparently varying between oceanic and land regions. The time‐integrated ELF energy of the associated sferics (and thus the lightning charge moment) exhibit much less tendency to be large. Statistical analysis of the spread in arrival time suggests a ∼2 ms variance due to factors other than geometry and measurement error.