VHF Direction Finder Studies of Lightning

MacClement, W. D.; Murty, R. C.

doi:10.1175/1520-0450(1978)017<0786:vdfsol>2.0.co;2

Cited by 7 publications

(2 citation statements)

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“…The results we show are consistent with the observations of MacClement and Murty [1978] and Taylor [1978]. They are consistent with those of Proctor [1976] with the notable exception of his P pulse propagation at nearly (and even in excess of) the speed of light.…”

Section: Two Features Dominated the Initial And Intracloud Portionssupporting

confidence: 90%

Two‐dimensional interferometric positions of VHF lightning sources

Hayenga¹,

Warwick²

1981

J. Geophys. Res.

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Using a new radio interferometric technique, we present observations of VHF lightning radiation source positions. The crossed base line interferometer provides the directions of arrival (azimuth and elevation) of VHF lightning radiation. Much flexibility exists in the choice of instrument parameters such as operating frequency and sampling interval. The present instrument operates at 34.3 MHz and provides an average position for every 2.5 μs of lightning radiation. Observations indicate that each 2.5 μs position should be attributed to a single discrete source in the sky. The positions of such sources define the temporal and spatial development of breakdown and rapid charge acceleration during the lightning flash. We have obtained VHF source positions correlated in time with electric field measurements. This allows us to identify the various processes occurring during a discharge and to compare the VHF phenomena with previously observed lightning phenomena. We have analyzed six flashes completely and portions of others. All six flashes contained ground strokes and two had intracloud discharges following the ground flash. We present data from three flashes that showed features common to the flashes we analyzed. The initial (preceding the first return stroke) and intracloud portions consisted of a large number of bursts of 20 μs average duration occurring on the average every 100 μs. The positions within each burst developed in a systematic, nearly linear, sequence with apparent speeds of ∼107 m/s. The relative positions from burst to burst drifted through the sky with speeds ∼105 m/s. In intracloud portions this drift was predominantly horizontal. In ground flashes the VHF sources drifted downward, in effect the leader for the first return stroke. They terminated at the return stroke.

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Section: Two Features Dominated the Initial And Intracloud Portionssupporting

confidence: 90%

Two‐dimensional interferometric positions of VHF lightning sources

Hayenga¹,

Warwick²

1981

J. Geophys. Res.

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“…There are two main effective techniques applied to determine the position of VHF/UHF radiation sources in order to track the locus of the stepped leader. The first one is the time of arrival (TOA) technique (Oetzel and Pierce, 1969;Proctor, 1971;Cianos et al, 1972;Murty and MacClement, 1973;MacClement and Murty, 1978;Proctor et al, 1988;Rison et al, 1999) that determines the location of radiations by taking differences between the times at which the radiation pulses are detected at each receiver. The other one is the narrowband interferometer system (Warwik et al, 1979;Hayenga and Warwik, 1981;Richard and Auffray, 1985;Laroche et al, 1994;Rhodes et al, 1994;Shao et al, 1995;Kawasaki and Yoshihashi, 2000) which uses frequency domain by taking differences of phases instead of times.…”

Section: Introductionsupporting

confidence: 52%

Broadband VHF sources locating system using arrival-time differences for mapping of lightning discharge process

Tantisattayakul

Masugata

Kitamura

et al. 2005

Journal of Atmospheric and Solar-Terrestrial Physics

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Lightning Locators

Shirer¹,

Roeder²,

Shirer³

et al. 2002

Encyclopedia of Imaging Science and Technology

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Locating lightning in real time is an old problem. Radio techniques developed in the early to mid‐twentieth century used crossed‐loop cathode‐ray direction finders (CRDF) that provide the bearing but not the range to the lightning source. Direction‐finding (DF) systems typically sense the radio signal, known as atmospherics , spherics , or ‘ sferics , that is emitted by lightning and that most listeners of AM radios interpret as interference, static , or radio noise . Quite generally, lightning radiates electromagnetic pulses that span an enormous range of frequencies. In this article, the radio signal refers to the portion of the electromagnetic spectrum that covers frequencies less than 3 × 10 8 kilohertz (denoted kHz), or 300 GHz, and the optical signal refers to frequencies greater than 3 × 10 8 kHz. Also, when not qualified here, electromagnetic radiation refers to the radio signal. Lightning sensing systems have important applications in meteorology. Certainly, these systems can help to detect and forecast the arrival of thunderstorms by monitoring their positions, motions, and intensities. Such systems are also important for lightning safety and for protecting natural resources in a diverse set of real‐time applications, including fire and personnel safety, aircraft routing, missile launch decisions, power grid operation, and weather forecasting. Lightning is a significant threat to people but far too often is underrated. Lightning sensing systems, especially those that detect intracloud lightning, are being investigated as tools for predicting severe thunderstorms, including tornadoes, microbursts, and hail. Lightning data are also being investigated as possible input for small‐scale numerical weather forecast models to supplement the usual observations of pressure, temperature, humidity, and winds. This article is not an exhaustive survey of all real‐time and research lightning location systems, but it provides a comprehensive overview of the topic. It is split into two major parts; the first reviews the many important concepts and defines the terminology used to describe them, and the second covers the different major types of operational lightning location systems by describing an example of each in detail. Many of the lightning facts herein are documented thoroughly in the references. The methods and detection systems reviewed in this article are also described on various World Wide Web (www) sites. The addresses for many of these sites are given.

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VHF Direction Finder Studies of Lightning

Cited by 7 publications

References 0 publications

Two‐dimensional interferometric positions of VHF lightning sources

Two‐dimensional interferometric positions of VHF lightning sources

Broadband VHF sources locating system using arrival-time differences for mapping of lightning discharge process

Lightning Locators

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