Seasonal and diurnal variation of ELF emission occurrences at 750-Hz band observed at geomagnetically conjugate stations

Journal Article · Mon Jun 01 00:00:00 EDT 1987 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/JA092iA06p06153· OSTI ID:5993662

Suzuki, Hiroyuki ^[1]; Sato, Natsuo ^[2]

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1. Yamagata Univ. (Japan)
2. National Inst. of Polar Research, Tokyo (Japan)

Statistical characteristics of emission occurrence are examined, using digital data of 750-Hz intensity records obtained at the conuugate pai of statins, Syowa Station in Antarrctica and Husafell in Iceland. The geographic local time at Syowa and Husafell is magnetic local time plus 3 hours and minur 1 hour, respectively. The following notable diurnal variations and seasonal variations were found: (1) The emissions were mostly observed during the daytime in the conjugate region. However, the magnetic local time when the emission occurrence rate reached maximum at Husafell was 2-3 hours later than that at Syowa. (2) The seasonal variations of emission occurrence showed the same tendency at the conjugate stations. The emission intensities showed a maximum during local summer and a minimum during local winter in both hemispheres. The ratio fo average emission intensity in each season to the intensity in winter is approximately 2.1-2.2 for summer, 1.7-1.9 for autumn, and 1.7 for spring. From these statistical characteristics, ELF emission intensity strongly depends on not only magnetic local time but also geographic local time and seasons, suggesting that ELF emissions observed on the ground are strongly controlled by the sunlight effects. The sunlight may affect the asymmetry of wave duct enhancement and wave propagation from the magnetosphere to the ionosphere in both hemisphers. Other effects are also discussed in this paper.

• OSTI ID: 5993662
• Journal Information: Journal of Geophysical Research; (United States), Vol. 92:A6; ISSN 0148-0227
• Country of Publication: United States
• Language: English

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71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AURORAL ZONES
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ANTARCTICA
AURORAL HISS
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GEOMAGNETIC CONJUGACY
ICELAND
NORTHERN HEMISPHERE
RADIO NOISE
SEASONAL VARIATIONS
SOLAR RADIATION
SOUTHERN HEMISPHERE
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ANTARCTIC REGIONS
DEVELOPING COUNTRIES
EARTH PLANET
EUROPE
ISLANDS
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NOISE
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STELLAR RADIATION
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661320* - Auroral
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