Since February 1985, the 2-MHz narrow beam radar near Adelaide, Australia, has been used to measure the short-term root-mean-square fluctuating velocities of radio wave scatterers in the altitude range 80--100 km. Data have been recorded about every 2 to 3 hours. This is in addition to the routine measurement of winds in the region between 60 and 100 km altitude. Under certain assumptions, these fluctuating velocities can then be converted to turbulent energy dissipation rates and eddy diffusion coefficients. These measurements are presented, and their interpretation as turbulence is discussed. The possibility of contamination from high frequency, short wavelength gravity waves is considered and a correction procedure to allow for such contamination is developed. It is concluded that the corrected measurements represent a good indication of turbulence activity. Between 84 and 92 km, the turbulence intensities were approximately constant with increasing height, but between 80 and 84 km turblence was relatively weak. Seasonal variations are discussed, and important interannual differences between 1985 and 1986 are noted. ¿ American Geophysical Union 1988 |