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Criteria for sprites and elves based on Schumann resonance observations

July 27, 1999
  |
Journal Article
Author:
Everest W. Huang
…
Published in:
J. Geophys. Res., Vol. 104, No. D14, 27 July 1999, pp. 16,943-16,964.
Topic:
weather
R&D area:
R&D group:

Summary

Ground flashes with positive polarity associated with both sprites and elves excite the Earth's Schumann resonances to amplitudes several times greater than the background resonances. Theoretical predictions for dielectric breakdown in the mesosphere are tested using ELF methods to evaluate vertical charge moments of positive ground flashes. Comparisons of the measured time constants for lightning charge transfer with the electrostatic relaxation time at altitudes of nighttime sprite initiation (50-70 km) generally validate the electrostatic assumption in predictions made initially by Wilson [1925]. The measured charge moments (Q dS = 200-2000 C-km) are large in comparison with ordinary negative lightning but are generally insufficient to account for conventional air breakdown at sprite altitudes. The measured charge moments, however, are sufficient to account for electron runaway breakdown, and the long avalanche length in this mechanism also accounts for the exclusive association of sprites with ground flashes of positive polarity. The association of elves with large peak currents (50-200 kA) measured by the National Lightning Detection Network in a band pass beyond the Schumann resonance range is consistent with an electromagnetic pulse mechanism for these events.
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Summary

Ground flashes with positive polarity associated with both sprites and elves excite the Earth's Schumann resonances to amplitudes several times greater than the background resonances. Theoretical predictions for dielectric breakdown in the mesosphere are tested using ELF methods to evaluate vertical charge moments of positive ground flashes. Comparisons of the...

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Criteria for sprites and elves based on Schumann resonance observations

Comparisons of long-term Schumann resonance records in Europe and North America

June 7, 1999
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Conference Paper
Author:
G. Satori
…
Published in:
11th Int. Conf. on Atmos. Electr. 7-11 June 1999, pp. 705-708.
Topic:
electrical engineering
R&D area:
R&D group:

Summary

Two stations at a distance comparable with the wavelength in the Schumann resonance (SR) frequency range, one in Europe (Nagycenk, Hungary) and one in North America (West Greenwich, Rhode Island) have simultaneously monitored the natural vertical electric and horizontal magnetic field components in the frequency range of 3-25 Hz. This is a unique opportunity, as Schumann resonance stations are scarce and even fewer station have records with 5-6 year durations. The main purpose of this paper is to make comparisons in the SR time series measured simultaneously at the two field sites, thereby providing access to global behavior on the seasonal and interannual time scales. The comparative measurements described here point out distinct differences in the nature of convection in South America and in Africa, and reveal new aspects about the behavior of tropical continental convection on the ENS0 time scale.
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Summary

Two stations at a distance comparable with the wavelength in the Schumann resonance (SR) frequency range, one in Europe (Nagycenk, Hungary) and one in North America (West Greenwich, Rhode Island) have simultaneously monitored the natural vertical electric and horizontal magnetic field components in the frequency range of 3-25 Hz. This...

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Comparisons of long-term Schumann resonance records in Europe and North America

The relationship between the background and transient signals in Schumann resonances

June 7, 1999
  |
Conference Paper
Author:
Earle R. Williams
…
Published in:
Proc. 11th Int. Conf. on Atmospheric Electricity, 7-11 June 1999, pp. 758-761.
Topic:
weather
R&D area:
R&D group:

Summary

Two distinct measures of the Earth's Schumann resonances -- the background and the transients -- are studied through comparisons at the mesoscale and at the continental scale. A rough proportionality is shown between the far more abundant afternoon lightning activity and the larger positive mesoscale discharges that make sprites and simultaneously ring the Earth- ionosphere cavity to levels higher than the integration of all other lightnings.
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Summary

Two distinct measures of the Earth's Schumann resonances -- the background and the transients -- are studied through comparisons at the mesoscale and at the continental scale. A rough proportionality is shown between the far more abundant afternoon lightning activity and the larger positive mesoscale discharges that make sprites and...

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The relationship between the background and transient signals in Schumann resonances

Total global lightning inferred from Schumann resonance measurements

December 27, 1998
  |
Journal Article
Author:
S. J. Heckman
…
Published in:
J. Geophys. Res., Vol. 103, No. D24, 27 December 1998, pp. 31,775-31,779.
Topic:
weather
R&D area:
R&D group:

Summary

Radiation with frequencies of 5-30 Hz is ducted between Earth's surface and ionosphere with little attenuation; at the lowest frequencies, waves travel several times around the Earth before losing most of their energy. Much of this radiation is produced by lightning. Here we assume that all of this radiation is produced by lightning, and attempt to invert the observed and electric and magnetic fields to infer global lightning activity. We show 10 days of inversions. For these 10 days, the inferred average rate of vertical charge transfer squared is only 1.7 105 (ten to the fifth) (Ckm)2/s Other studies suggest that the root mean square moment change of a flash is about 166 Coulomb kilometers. If we naively assume that each of these flashes is composed of four equally sized strokes, then we conclude that our entire observed signal could be produced by only 22 flashes per second.
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Summary

Radiation with frequencies of 5-30 Hz is ducted between Earth's surface and ionosphere with little attenuation; at the lowest frequencies, waves travel several times around the Earth before losing most of their energy. Much of this radiation is produced by lightning. Here we assume that all of this radiation is...

READ MORE
Total global lightning inferred from Schumann resonance measurements
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