The Coupling of Gravity Waves and Turbulence at White Sands, New Mexico, from VHF Radar Observations

Doppler spectra taken with the VHF Doppler radar at White Sands Missile Range are used to describe the winds and turbulence for 10 days in March-April 1991. The large power aperture product of this radar provides excellent data coverage in 150-m layers over the entire height range used, about 5-20 km. The results show that gravity-wave activity and small-scale turbulence are significantly enhanced at all levels during times when wind speeds in the troposphere, near 5.6 km (about 500 hPa). are strong. Largest enhancements are found in the lower stratosphere, near 16-18 km, where the mean logC;; is increased by over 10 dB during times of strong winds at low levels. Mean winds, wind shears, and static stability in the lower stratosphere were found to be nearly the same, regardless of wind speeds at low levels. The authors conclude that the enhanced turbulence is due to an effect not described by the local background wind and static stability, and suggest that this effect is upward-propagating gravity waves launched in the troposphere during the periods of strong winds.