Gravity wave excitation through resonant interaction in a compressible atmosphere

Abstract

Starting from a set of fully nonlinear equations, the whole process of a gravity wave excited through resonant interaction under sum resonant conditions is clearly exhibited. In the whole interaction, the wavelength and frequency of the excited wave are in agreement with the values derived from the sum resonant conditions. And the energy growth of the excited wave is mainly from the primary wave. Moreover, strong energy exchange in the interaction shows that the nonlinear interaction may play a significant role in determining the atmospheric wave spectrum and transporting the momentum to higher altitudes. A discussion on the resonant and nonresonant interactions is also presented, and the detuning degree of interaction is proposed, which may be applied to measure whether or not the effective energy exchange occurs in the nonlinear interactions of gravity waves.