Tidal Oscillations in the Thermosphere and Their Implications for Upper Atmosphere Density Models.
A study of the variation of atmospheric parameters in the lower thermosphere (80-150 km) in terms of the theory of atmospheric tides. The existing tidal theory is expanded to include the effects of dissipation and excitation in the thermosphere. The effects of heat conductivity and absorption of solar radiation in the thermosphere are added to the existing tidal theory. The results are then compared with observations of winds in the lower thermosphere to determine the extent to which the tidal theory can explain the observed variations of meteorological variables in the lower thermosphere. Results indicate that many features of lower thermospheric wind profiles can be explained in terms of tidal theory, including the effects of dissipation and thermospheric heating. However, additional dissipation and, for some tidal modes, additional excitation is indicated. Further development of the tidal theory will lead to an atmospheric density model in the range of 100-150 km that can be used for improved satellite position predictions.