Onset conditions for equatorial spread F

Journal Article · Tue Sep 01 04:00:00 EDT 1992 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/92JA00647· OSTI ID:6967489

Mendillo, M; Baumgardner, J; Pi, Xiaoqing; Sultan, P J ^[1]; Tsunoda, R ^[2]

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1. Boston Univ., MA (United States)
2. SRI International, Menlo Park, CA (United States)

The problem of day-to-day variability in the occurrence of equatorial spread F (ESF) is addressed using multidiagnostic observations and semiempirical modeling. The observational results are derived from a two-night case study of ESF onset conditions observed at Kwajalein Atoll (Marshall Islands) using the ALTAIR incoherent scatter radar and all-sky optical imaging techniques. The major difference between nights when ESF instabilities did not occur (August 14, 1988) and did occur (August 15, 1988) in the Kwajalein sector was that the northern meridional gradient of 6300-[angstrom] airglow was reduced on the night of limited ESF activity. Modeling results suggest that this unusual airglow pattern is due to equatorward neutral winds. Previous researchers have shown that transequatorial thermospheric winds can exert a control over ESF seasonal and longitudinal occurrence patterns by inhibiting Rayleigh-Taylor instability growth rates. They present evidence to suggest that this picture can be extended to far shorter time scales, namely, that 'surges' in transequatoral winds acting over characteristic times of a few hours to a day can result in a stabilizing influence upon irregularity growth rates. The seemingly capricious nature of ESF onset may thus be controlled, in part, by the inherent variability of low-latitude thermospheric winds.

• OSTI ID: 6967489
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 97:A9; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

661320* -- Auroral
Ionospheric
& Magnetospheric Phenomena-- (1992-)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AIRGLOW
DAILY VARIATIONS
EARTH ATMOSPHERE
F REGION
INSTABILITY
INSTABILITY GROWTH RATES
IONOSPHERE
MATHEMATICAL MODELS
MEASURING INSTRUMENTS
PLANETARY IONOSPHERES
RADAR
RANGE FINDERS
RAYLEIGH-TAYLOR INSTABILITY
SPREAD F
THERMOSPHERE
VARIATIONS
WIND