损耗大气中随机重力波场的传输方程

TRANSPORT EQUATION OF INTERNAL GRAVITY WAVES IN A DISSIPATIVE ATMOSPHERE

从包含分子粘性的非线性相互作用方程出发,采用随机相位近似,推导了损耗大气中重力波场的非线性传输方程。由于分子损耗的引入,谱演变的速率发生了改变,在某些情况下,还会得到与无耗条件下的传输规律相反的结论。损耗大气中重力波场的传输方程是研究中高层大气重力波能量收支平衡的出发点。

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.