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Author Buonsanto, M. J.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS ♦ THERMOSPHERE ♦ WIND ♦ COLORADO ♦ DAILY VARIATIONS ♦ ELECTRIC FIELDS ♦ LAYER ♦ FOURIER ANALYSIS ♦ IONIZATION ♦ LATITUDE EFFECT ♦ MATHEMATICAL MODELS ♦ SEASONAL VARIATIONS ♦ SOLAR CYCLE ♦ DEVELOPED COUNTRIES ♦ EARTH ATMOSPHERE ♦ F REGION ♦ FEDERAL REGION VIII ♦ GEOGRAPHICAL VARIATIONS ♦ IONOSPHERE ♦ NORTH AMERICA ♦ PLANETARY IONOSPHERES ♦ USA ♦ VARIATIONS ♦ Atmospheric Physics
Abstract The magnetic meridional component of the thermospheric neutral wind at the F2 peak at Boulder, Colorado, is derived for days with magnetic index Ap {le} 20 over solar cycle (July 1975-June 1986). The servo model technique and ionosonde measurements of hmF2 are used, and the results are corrected for ionization drifts due to electric fields. A Fourier decomposition of the mean daily variation is carried out for each month. This reveals significant components with wave periods of 24, 12, 8, and 6 hours. The importance of ion drag in causing seasonal and solar cycle variations in the winds is inferred. Specifically, the conclusion of previous work that the diurnal amplitude is generally in the range 60-80 m s{sup {minus}1} at solar minimum but only 25-45 m s{sup {minus}1} at solar maximum. The diurnal phase maximum of the northward wind lies in the range 1115-1625 LT with latest values in winter and at solar maximum, when the daytime effects of ion drag are greatest. The amplitude of the semidiurnal component shows little solar cycle variation but tends to be smaller in summer compared to other seasons. It has a mean value of 41 m s{sup {minus}1} over the solar cycle. The amplitudes of the 8 and 6 hour waves are both in the range 4-25 m s{sup {minus}1}. The 8 and 6 hour waves both have later phase maxima in summer than in winter. The present results are generally consistent with currebt models of atmosperic tides, except for the large solar cycle variation in the diurnal component.
ISSN 01480227
Educational Use Research
Learning Resource Type Article
Publisher Date 1991-03-01
Publisher Place United States
Journal Journal of Geophysical Research
Volume Number 96
Issue Number A3


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