Evidence for strongly damped gravity waves in the earth's atmosphere

Data from a series of pitot tube rocket soundings of the atmosphere are examined. The experiments consist of four soundings carried out over a twoday period at Fort Churchill, Canada in January and February 1967 by Smith, Theon and Horvath. Temperature data from the four soundings were averaged, and a smooth curve was drr-.wn through the points. A hydrostatically determined atmosphere based on the above lapse rate was calculated. Deviations from the above mean atmosphere were calculated, and a wavelike structure was observed. The waves grow very slowly below approximately 80 km, and acquire a more rapid growth rate at higher altitudes. The density and temperature variations have a wavelength of 10-20 km and appear to consistently be about 180 degrees out of phase. The pressure variation is somewhat irregular. However, in regions '%,here pressure variation is well behaved it is out of phase with temperature and density by about 90 degrees. Volland's theory of thermally damped gravity waves was used to compute wave patterns like those observed experimentally. A highly damped., upward propagating wave gives good results. Damping by conduction, turbulence and radiative transfer is examined, and turbulence is found to be the most important. *NRC-NASA Research Associate I