| Radio Physics and Radio Astronomy |
Vol. 11, 2006, No.1, March, p.49 |
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Atmospheric Gravity Waves Generation by Solar Terminator According to “Atmosphere Explorer-E” Satellite Data
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G.V. Lizunov and A.K. Fedorenko1
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Киевский национальный университет имени Тараса Шевченко, пр. Академика Глушкова, 6, г. Киев, 03022, Украина, E-mail:liz@ikd.kiev.ua 1Институт космических исследований НАНУ-НКАУ, пр. Академика Глушкова, 40, г. Киев, 03680, Украина, E-mail:aurora@space.is.kiev.ua
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| The upperatmospheric neutral and ionized components dynamical response on a moving solar terminator is investigated employing the direct satellite measurements. The observations from “Atmosphere Explorer-E” are analyzed for the period of the satellite being in a circular near-equatorial orbit with the inclination i=19.7° and height 250-300 km. It came to light that the terminator generates the large-scale atmospheric gravity waves (AGW) and traveling ionospheric disturbances (TID) with the following parameters: the horizontal wavelength of about 1200-1600 km; the calculated period of about 50 min; the wavetrain duration of four-to-six periods; the relative AGW amplitude of several percent; the relative TID amplitude at sunrise terminator of about several percent, rising to tens percent at sunset terminator. The primary ion O+ density oscillates in opposite phase, while that of molecular ions NO+ and O2+ does in phase, with the density oscillations of the main neutral components N2 and O. The experimental findings are interpreted in terms of the theory of AGW propagation in a multi-component gas medium. It is shown that the amplitude and phase distinctions in the oscillations of atmospheric components (including the main ionic component O+) are caused by the differences in their vertical distributions above the turbo-pause. The mechanism of AGW and TID generation at the F-region heights due to electron gas pressure gradient is suggested. |
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