By using the spectral allocation method, the energy propagation and the characteristics of energy conversion in the excitation of gravity waves by initially given two-variable wave-like disturbances is numerically studied. The simulation results show that when the relative amplitudes and phases of the two initially given wave-like disturbance variables satisfy strictly the polarization relation of gravity waves, only this two-variable disturbance which variables are horizontal wind and temperature can restrict the downward energy propagation of gravity waves. In general cases, A two-variable wave-like disturbance will excite two gravity-wave packets, one propagates upward and the other downward, moreover, the ratio of wave energy for those two gravity waves is decided evidently by the relation of the amplitudes for the two initial disturbance variables, when the ratio satisfies certain condition, only one upward propagating gravity wave can be excited. Further numerical analysis shows that, both the energy propagation paths and velocities in all numerical cases are identical with each other. Compared with the results of energy conversion for gravity waves excited by single-variable disturbances, the characteristic times of the energy conversion for gravity waves in the cases present in this paper are the same, but the efficiencies of energy conversion are larger.
DownLoad: