Statistical analysis of storm electrical discharges reconstituted from a lightning mapping system, a lightning location system, and an acoustic array

Abstract

In the framework of the European Hydrological Cycle in the Mediterranean Experiment project, a field campaign devoted to the study of electrical activity during storms took place in the south of France in 2012. An acoustic station composed of four microphones and four microbarometers was deployed within the coverage of a Lightning Mapping Array network. On the 26 October 2012, a thunderstorm passed just over the acoustic station. Fifty‐six natural thunder events, due to cloud‐to‐ground and intracloud flashes, were recorded. This paper studies the acoustic reconstruction, in the low frequency range from 1 to 40 Hz, of the recorded flashes and their comparison with detections from electromagnetic networks. Concurrent detections from the European Cooperation for Lightning Detection lightning location system were also used. Some case studies show clearly that acoustic signal from thunder comes from the return stroke but also from the horizontal discharges which occur inside the clouds. The huge amount of observation data leads to a statistical analysis of lightning discharges acoustically recorded. Especially, the distributions of altitudes of reconstructed acoustic detections are explored in detail. The impact of the distance to the source on these distributions is established. The capacity of the acoustic method to describe precisely the lower part of nearby cloud‐to‐ground discharges, where the Lightning Mapping Array network is not effective, is also highlighted.

Acoustical Measurement of Natural Lightning Flashes: Reconstructions and Statistical Analysis of Energy Spectra

“…Gallin et al () summarized the different works who compared and validated acoustic and EM reconstructions (see Arechiga et al, , ; Bodhika et al, ; Johnson et al, ; Qiu et al, ). Gallin et al () also presented an improved method of reconstruction using the Progressive MultiChannel Correlation (PMCC) algorithm (Cansi, ) briefly described in section 2.2 along with a statistical comparison to EM lightning channel reconstructions. In particular, Gallin et al (, figure 6d) pointed out the possibility to isolate in some cases return strokes within the overall signal.…”

“…Gallin et al () also presented an improved method of reconstruction using the Progressive MultiChannel Correlation (PMCC) algorithm (Cansi, ) briefly described in section 2.2 along with a statistical comparison to EM lightning channel reconstructions. In particular, Gallin et al (, figure 6d) pointed out the possibility to isolate in some cases return strokes within the overall signal. Signal spectrograms were also shown but were limited to the range of [0.1 − 40] Hz.…”

“…The objective of this paper is to reconstruct lightning channels from acoustic data over a wide frequency band and comparing these results to EM reconstructions. In particular, the separation method of return strokes suggested by Gallin et al () will be enhanced here and applied to 27 flashes in the range of [0.1 − 180] Hz. This will allow us to investigate more precisely the frequency content of return stroke spectra and to provide new insight into the origin of thunder infrasound.…”

Toward an Improved Representation of Middle Atmospheric Dynamics Thanks to the ARISE Project

“…An example of infrasound inversion, providing the origin of the infrasound sources inside the lightning structure, is shown in Fig. 9 (Gallin et al 2016). The good agreement between the infrasound observations and the observations of the lightning mapping array validated the infrasound inversions.…”

“…Large thunderstorm systems are able to produce high-energy transient events such as transient luminous events (TLE) or terrestrial gammaray flashes (TGF) which were both discovered in the 1990s (Sentman and Wescott 1993; (Gallin et al 2016). This method also allowed retrieving infrasound origin inside the sprite structures up in the stratosphere and mesosphere up to 100 km altitude.…”