TRANSPORT EQUATION OF INTERNAL GRAVITY WAVES IN A DISSIPATIVE ATMOSPHERE

Observed atmospheric gravity wave field consists of a large number of ensemble of spectral components with various spatial and temporal scales. Nonlinear interaction may yield energy transfers among the spectral components, consequently resulting in an evolution of wave spectrum. This is called the internal transfer process in the gravity wave spectrum. Starting from the nonlinear interaction equations of gravity waves in a disspative atmosphere, a transport equation is derived by using the ’random phase approximation’. Since the molecular dissipation is taken into account, the evolution rate of the gravity wave spectrum has been changed. The transport equation provides a basis for studying the budget and balance of gravity wave energy in the middle and upper atmosphere.