A procedure is developed to derive the vertical phase and group velocities of waves from measurements of ionograms. We apply the developed procedure to a sequence of ionograms recorded by the digisonde portable sounder in Taiwan and find numerous waves occuring in the ionosphere during the solar eclipse of 24 October 1995. A detailed analysis of an 87-min period wave shows that the vertical phase velocities of the wave below and above the F1 ledge are about 100 m/s in the downward and upward directions, respectively. The associated group velocities below and above the ledge are found to be about 10 m/s in the downward and upward directions, respectively, which indicates that during the solar eclipse the wave source is near the F1-ledge.
|頁（從 - 到）||1679-1686|
|期刊||Journal of Atmospheric and Solar-Terrestrial Physics|
|出版狀態||已出版 - 15 11月 1998|