Mapping lightning in the sky with a mini array

Martin Füllekrug , Zhongjian Liu , Kuang Koh , Andrew Mezentsev , Stéphane Pedeboy (1) , Serge Soula (2) , Sven-Erik Enno , Jacqueline Sugier , Michael J. Rycroft

1 METEORAGE
2 LAERO - Laboratoire d'aérologie

Mini arrays are commonly used for infrasonic and seismic studies. Here we report for the first time the detection and mapping of distant lightning discharges in the sky with a mini array. The array has a baseline to wavelength ratio ∼4.2·10^-2 to record very low frequency electromagnetic waves from 2 to 18 kHz. It is found that the mini array detects ∼69 lightning pulses per second from cloud-to-ground and in-cloud discharges, even though the parent thunderstorms are ∼900-1100 km away and a rigorous selection criterion based on the quality of the wavefront across the array is used. In particular, lightning pulses that exhibit a clockwise phase progression are found at larger elevation angles in the sky as the result of a birefringent subionospheric wave propagation attributed to ordinary and extraordinary waves. These results imply that long range lightning detection networks might benefit from an exploration of the wave propagation conditions with mini arrays.

Mots clés: atmospheric and space electricity; lightning discharges; array analysis; electromagnetic noise and interference; wave propagation

Domaines: Planète et Univers [physics]; Sciences de la Terre

Martin Füllekrug, Zhongjian Liu, Kuang Koh, Andrew Mezentsev, Stéphane Pedeboy, et al.. Mapping lightning in the sky with a mini array. Geophysical Research Letters, 2016, 43, pp.10,448-10,454. ⟨10.1002/2016GL070737⟩. ⟨insu-03671660⟩