Acoustic-gravity waves (AGWs) observed in the upper atmosphere may be generated near the Earth’s surface due to different sources. Two–dimension simulation of vertical propagation and breaking of nonlinear AGWs in the atmosphere is made. Forcing near Earth’s surface is used as AGW source in the model. We use a numerical method based on finite–difference analogues of fundamental conservation laws for solving atmospheric hydrodynamic equations. This feature selects physically correct generalized solutions of the wave hydrodynamic equations. Numerical simulation was made in a region of the Earth atmosphere with dimensions up to 1200 km horizontally and 500 km vertically. Vertical profiles of temperature, density, molecular viscosity and heat conductivity were taken from the standard atmosphere model MSIS-90 for January. Calculations were made for different amplitudes and frequencies of lower boundary forcing. It is shown that after “switching on” tropospheric forcing atmospheric waves very quickly (for several