Energetics and dynamics of the Earth’s thermosphere

The Earth's thermosphere, i.e., the region above the mesopause (∼80–90 km) where the neutral gas temperature increases towards an asymptotic value determined by the variable sources of solar heating, has remained the subject of extensive experimental and theoretical study during the last few years. Since the time of the previous IUGG quadrennial report, results from several comprehensive experimental undertakings have been reported and the theoretical and semi‐empirical models of the region have matured considerably. Previous reviews in this series by Dickinson (1975), Mayr and Harris (1979), and Roble (1983a) have charted the progress made in our understanding of the thermosphere up to 1982. Other valuable review articles have appeared over the years that have concentrated on various aspects of thermospheric research including composition and variability [Carignan, 1975; Hedin, 1979; Prölss, 1980; Prölss and Roemer, 1985, 1987], incoherent scatter radar observations [Evans, 1975], tides and tidal forcing [Evans, 1978; Forbes and Garrett, 1979; Lindzen, 1979; Forbes, 1984], gravity waves [Hunsucker, 1982; Fritts 1984], ionospheric processes and electrodynamics [Richmond, 1983, 1986], thermospheric photochemistry [Torr, 1985; Torr and Torr, 1982; Roble, 1986a], atmospheric emissions [Bates, 1982, 1983; Vallance Jones et al, 1985] and thermospheric winds and temperatures [e.g., Straus, 1978; Rishbeth, 1979, 1982; Meriwether, 1983; Killeen, 1985; Rees, 1985; Mayr et al, 1985; Roble, 1983b,1986b].