Excitation of Earth-ionosphere cavity resonances by sprite-associated lightning flashes



Simultaneously recorded discrete excitations of Earth-ionosphere cavity resonances at Silberborn, Germany, and Hollister, California, ∼9.1 Mm apart, are used to triangulate source locations of lightning flashes in the continental United States with an accuracy of ∼0.8 Mm, as verified by the National Lightning Detection Network. The identified lightning flashes are mainly associated with positive cloud-to-ground discharges with first return stroke peak currents ∼20–70 kA. 80% of these particular lightning flashes are associated with sprites, as verified by simultaneous low-light level TV camera observations at Yucca Ridge, Colorado. This high probability of sprite detection is attributed to particularly large cloud-to-ground lightning currents, simultaneously exciting both Earth-ionosphere cavity resonances and sprites.