Observations of upper stratospheric short period gravity waves using the Jicamarca VHF radar

Reliable upper stratospheric vertical wind velocities have been, for the first time, observed in the so-called “gap region” from 30 to 60 km heights using the Jicamarca VHF Doppler radar in Peru, which has been recently improved in height resolution. These wind velocities indicate conspicuous short-period oscillations with time scale of 10-20 min both in stratosphere and mesosphere. Spectral analysis shows that these oscillations are related to the same mode of internal gravity wave. The height profiles of the wave amplitude suggests standing wave-like structure of upward and downward propagating waves with vertical scale of about 60 km