Using a quasi one-dimensional model, in which the latitudinal distributions of variables are assumed and only the vertical dependence is explicitly treated, the general circulation of the middle atmosphere interacting with internal gravity waves is treated. An ensemble of internal gravity waves with an isotropic spectrum are introduced at the lower boundary and their propagation in the prevailing zonal wind field are determined incorporating the effect of eddy viscosity, in the same way as done by Plumb and McEwan (1978). As the result of selective transmission due to the background wind effect, deceleration of the stratomesospheric wind system and generation of a reverse flow take place near and above the mesopause level, owing to the wave momentum flux. Results of numerical calculations are compared with those obtained by using the conventional Rayleigh friction.
Meteorological Society of Japan