Mapping thunder sources by inverting acoustic and electromagnetic observations

Abstract

We present a new method of locating current flow in lightning strikes by inversion of thunder recordings constrained by Lightning Mapping Array observations. First, radio frequency (RF) pulses are connected to reconstruct conductive channels created by leaders. Then, acoustic signals that would be produced by current flow through each channel are forward modeled. The recorded thunder is considered to consist of a weighted superposition of these acoustic signals. We calculate the posterior distribution of acoustic source energy for each channel with a Markov Chain Monte Carlo inversion that fits power envelopes of modeled and recorded thunder; these results show which parts of the flash carry current and produce thunder. We examine the effects of RF pulse location imprecision and atmospheric winds on quality of results and apply this method to several lightning flashes over the Magdalena Mountains in New Mexico, USA. This method will enable more detailed study of lightning phenomena by allowing researchers to map current flow in addition to leader propagation.

Detecting Lightning Infrasound Using a High‐Altitude Balloon

“…For the ray propagation and eigenray modeling we have assumed a point source for the lightning infrasound at 4‐km altitude. Infrasound sources from lightning have been mapped up to 12‐km altitude in the thundercloud (J. F. Anderson et al, ; Arechiga et al, ). Furthermore, the mapped current flow within lightning strokes suggests that the source geometry can resemble complex, dendritic structures (J. F. Anderson et al, ).…”

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

“…Acoustic Data Teer and Few [1974] 17 CG and 20 IC [Arizona storm, also studied in MacGorman et al 1981] MacGorman et al [1981] statistics on three storms: Arizona (26 + 11 flashes), Colorado (35 flashes), and Florida (9 flashes) Arechiga et al [2011] two triggered lightning flashes Johnson et al [2011] at least 24 natural lightning flashes Qiu et al [2012] two natural lightning flashes Bodhika et al [2013] two natural lightning flashes, no comparison with LMA Arechiga et al [2014] two intracloud natural lightning flashes Anderson et al [2014] eight natural lightning flashes camera . The authors found a good agreement between the acoustic reconstructions and the pictures when the discharge is visible, being outside the storm cloud.…”

“…The determination of uncertainties associated to acoustic reconstructions is an active research field: Arechiga et al [2014] and Anderson et al [2014] discussed the impact of meteorological profiles on localization.…”

Diverse Eruptive Activity Revealed by Acoustic and Electromagnetic Observations of the 14 July 2013 Intense Vulcanian Eruption of Tungurahua Volcano, Ecuador

“…These glitches include a one-sample voltage spike preceded and followed by brief oscillations (presumably induced by the data logger's antialiasing filter); they appear on all channels within the same sample interval (0.001 s) with distinct waveforms ( Figure S3). Such characteristics are unlikely for acoustic waves but are typical of glitches observed to coincide with lightning strikes during thunderstorms, which are interpreted as electromagnetic interference from radio waves generated during lightning strikes (Anderson et al, 2014). Volcanic lightning is common in explosive eruptions and forms as a result of charging due to violent interactions between ash particles or, if present, hydrometeors (Behnke et al, 2013;Cimarelli et al, 2014).…”