Location of lightning discharges from a single station

Abstract

A new computer‐based ELF/VLF system for locating lightning discharges has been developed. Both the arrival azimuths of atmospherics and the distances to their sources are estimated. The direction‐finding technique uses the Poynting vector calculated directly in the time domain over the full band pass of the receiver. Both the distance of the lightning discharge and the ionospheric height can be estimated from the phase spectrum of the first‐order mode of the Earth‐ionosphere waveguide. The latter is approximated with a model function having the distance and the height as the main parameters. Two ways were applied to obtain the spectrum of the first mode: the radial component of the horizontal magnetic field was used, which contains only a minor component of the zeroth mode, or the mode decomposition problem was solved. The system has been used to locate lightning sources in Africa and Asia from a scientific vessel during its voyage in the Atlantic and Indian Oceans in 1991. The overall uncertainties are estimated to be a few degrees for the source bearing, 5% for distance, and 1% for the effective height of the ionosphere; yet these estimates need an additional confirmation by comparison with independent and more exact techniques.

Characteristics of VLF atmospherics near the resonance frequency of the Earth-ionosphere waveguide 1.6–2.3 kHz by observations in the auroral region

“…Transverse resonance of the Earth-ionosphere cavity is observed at ELF-VLF frequencies which is well documented and interpreted (e.g. Rafalsky et al, 1995). The transverse resonance frequencies are f p = p c 2h , where p=1, 2, .…”

“…Nickolaenko and Hayakawa, 2002). Special observations of transverse resonance were reported in a few works (Belyaev, 1991;Lazebnyi et al, 1988;Rafalsky et al, 1995;Shvets, 1997;Shvets and Hayakawa, 1998;Brundel et al, 2002;Shvets, 2008). Significant maxima of the power spectra were found at multiples of the frequency ∼2 kHz at the middle and low latitudes.…”

“…The idea of using the ELF-VLF natural pulsed radio signals to study the ionosphere and Correspondence to: E. E. Titova (lena.titova@gmail.com) the lightning strokes was addressed in many works (see e.g. Hayakawa et al, 1994Hayakawa et al, , 1995Rafalsky et al, 1995;Cummer, 1997, and references therein).…”

Location accuracy of long distance VLF lightning locationnetwork

“…One such technique was validated by comparing the single station determined positions with those reported by a commercial lightning detection network . Making use of 85 sferics observed at near Darwin, Australia, it was found that the 68% accuracy limits for the "Kharkov" single station lightning location method (developed by Rafalsky et al, 1995) were ∼4 • in bearing and ∼73 km in range . In this paper we will concentrate upon an another approach which makes use of the considerable sferic power present in the VLF band (3-30 kHz), such that very-long range remote sensing is possible; these VLF signals can be received thousands of kilometres from the source (Crombie, 1964)), as the electromagnetic energy propagates with low attenuation inside the waveguide formed by the conducting Earth and the lower boundary of the ionosphere, termed the Earth-Ionosphere Waveguide (EIWG).…”

“…Techniques have been developed to allow a single-station lightning location (which might be more appropriate for an aircraft or vessel), often by combining a direction finding method with a procedure by which the distance of the lightning discharge can be estimated (see the review in Rafalsky et al (1995)). One such technique was validated by comparing the single station determined positions with those reported by a commercial lightning detection network .…”