The importance of small-scale gravity waves in the middle atmosphere: a modeller's perspective (Invited Speaker)

Gravity waves are now realized to play a crucial role in the large-scale circulation of the middle atmosphere, especially the upper mesosphere and lower thermosphere where the drag they produce is responsible for the observed zonal mean wind and temperature structure. Since their horizontal scales are too small to be resolved by current middle atmosphere climate models, the effects of gravity waves must be parameterized if realistic simulations of the large-scale circulation are to be obtained. This talk, which is general in nature and aimed at a wide audience, will outline the problem of parameterizing gravity waves in middle atmosphere models. Robust versus nonrobust responses to gravity waves drag parameterizations will also be discussed.