A numerical simulation on gravity waves propagation in mesospheric thermal duct
重力波包在中层大气温度波导中传播的数值模拟

The linear theory of antisymmetric ducted gravity waves supported by mesospheric thermal duct is presented, propagation and evolution of gravity wave packets in thermal duct is also simulated by using a nonlinear two-dimensional model. Numerical results show that lower atmospheric wave disturbance can penetrate into the duct area and be trapped. Gravity waves keep reflecting between two boundaries of the thermal duct, and wave energy is transported horizontally through the duct. Characteristics of gravity waves calculated from simulated results are little different to those derived from the linear duct theory. While wave packets propagate in the thermal duct, wave energy will be leaked. However some energy is always restricted in the duct area, for the loss rate of energy gradually decreases. Wave structures keep well after propagating horizontally for hundreds of kilometers, and evolution of the energy density distribution in the duct is also presented.