ELF sferic energy as a proxy indicator for sprite occurrence

Broadband ELF/VLF measurements of sferics near Ft. Collins, Colorado, demonstrate that ELF sferic energy is a proxy for sprite occurrence which can be used to estimate the number of sprites produced by a thunderstorm. Ultra-long range (similar to 12,000 km) measurements at Palmer Station, Antarctica, confirm the application of this proxy to storms where no video observations of sprites are available. Comparison with high-resolution photometer measurements demonstrate the simultaneity of sprite luminosity and an ELF "second pulse" believed to be radiated by electrical currents within the sprite body [Cummer et al., 1998]. Measurements of the second ELF pulse are used to identify a quantitative relationship between the current in sprites and total sprite luminosity.