Journal cover Journal topic
Annales Geophysicae Sun, Earth, planets, and planetary systems An interactive open-access journal of the European Geosciences Union
Ann. Geophys., 16, 821-827, 1998
© European Geosciences Union 1998
31 Jul 1998
Incoherent scatter radar observations of AGW/TID events generated by the moving solar terminator
V. G. Galushko1, V. V. Paznukhov1, Y. M. Yampolski1, and J. C. Foster2 1Institute of Radio Astronomy, National Academy of Sciences of Ukraine, Kharkov, Ukraine
2MIT Haystack Observatory, Atmospheric Sciences Group, Westford, MA 01886, USA
Abstract. Observations of traveling ionospheric disturbances (TIDs) associated with atmospheric gravity waves (AGWs) generated by the moving solar terminator have been made with the Millstone Hill incoherent scatter radar. Three experiments near 1995 fall equinox measured the AGW/TID velocity and direction of motion. Spectral and cross-correlation analysis of the ionospheric density observations indicates that ST-generated AGWs/TIDs were observed during each experiment, with the more-pronounced effect occurring at sunrise. The strongest oscillations in the ionospheric parameters have periods of 1.5 to 2 hours. The group and phase velocities have been determined and show that the disturbances propagate in the horizontal plane perpendicular to the terminator with the group velocity of 300-400 m s-1 that corresponds to the ST speed at ionospheric heights. The high horizontal group velocity seems to contradict the accepted theory of AGW/TID propagation and indicates a need for additional investigation.

Key words. Ionosphere (wave propagation) · Meteorology and atmospheric dynamics (waves and tides)

Citation: Galushko, V. G., Paznukhov, V. V., Yampolski, Y. M., and Foster, J. C.: Incoherent scatter radar observations of AGW/TID events generated by the moving solar terminator, Ann. Geophys., 16, 821-827,, 1998.
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