GENERATION OF TURBULENCE IN THE UPPER ATMOSPHERE BY INTERNAL GRAVITY WAVES.

If turbulence is a produced, rather than intrinsic, property of the upper atmosphere, then it is necessary to identify mechanisms that can create turbulence in an initially quiescent region of the atmosphere. Wind shears of sufficient magnitude to do this have a very slight probability of occurrence. However, the density fluctuations that must accompany internal gravity waves must often be of sufficient amplitude to produce convective instabilities in thin layers that propagate with the waves. This is suggested as an important mechanism for the production of turbulence in an initially quiescent region of the upper atmosphere.