High-resolution upper tropospheric and lower stratospheric (5-30 km) wind data were obtained during three periods from 1979 to 1981 with the aid of the high-power UHF radar at Arecibo. Detailed discussion of these data is made in light of internal inertia-gravity waves. The vertical scale and dominant period of the observed quasiperiodic oscillation are estimated. The vertical propagation characteristics of the wave are investigated with consideration for the Doppler shift effect due to the mean zonal flow. Quantitative results on the nature of the waves are obtained based on the dispersion equation for internal gravity waves with the Coriolis frequency (f-phase analysis) included. Oscillation with somewhat larger vertical scale is presented and its relationships with the inertia-gravity waves is discussed. Refs.