Nonlinear Propagation of Finite-Amplitude Gravity Wave Packet in an Isothermal Compressible Atmosphere

By using the Alternative-Direction-Implicit(ADI) scheme,a fully nonlinear,compressible and two-dimensional model is developed to numerically study the nonlinear propagations of gravity-wave-packets with different initial amplitude.The simulations show that the nonlinear effects depend strongly on the wave amplitude.The nonlinearity will damp the wave amplitude growth significantly,change the vertical wave numbers,and alter obviously the vertical velocity of energy transmission.The mean flows are accelerated extensively and greatly in the nonlinear propagation of a gravity wave packet with large amplitude.