损耗大气中惯性重力波的非线性相互作用方程及其初步讨论

根据弱相互作用理论，本文建立了损耗大气中惯性重力波的非线性相互作用方程，这组方程在三个方面推广了前人的工作：考虑了波的空间传播；包含了粘滞产生的衰减，波谱可以是连续的。粘滞衰减率的大小与空间尺度以及传播方向有关，Ｃｏｒｉｏｌｉｓ力的引入使相互作用系数成为复量。根据这组方程，考察了惯性重力波的参量激发，结果表明：在共振条件满足时，主波存在一个值，阈值大小与次级波的损耗率成正比，当主波振幅大于这个阈值

NONLINEAR INTERACTION EQUATIONS OF INERTIAL GRAVITY WAVES IN A DISSIPATIVE ATMOSPHERE AND THEIR PRELIMINARY DISCUSSION

A set of the interaction equations of inertial gravity waves in a dissipative atmosphere on the basis of the weak nonlinear theory is derived. This work generalizes previous studies by including the effects of spatial propagation, viscous dissipation and continuous spectrum. It is shown that the wave dissipation rate produced by viscosity depends on the spatial scale and propagation direction of inertial gravity waves. Coriolis effect makes the interaction coefficients complex. Starting from the equations we examined the parametric instability of inertial gravity waves. It is indicated that there exists a threshold of primary wave amplitude. The magnitude of the threshold is proportional to the dissipation rate of secondary waves. When the primary wave amptitude exceeds the threshold, the secondary waves grow exponentially.The interaction brings about a variation in the frequencies of the secondary waves. The magnitude of the variation is proportional to the energy density of the primary wave.