中层大气对对流层扰动的响应

By applying the numerical simulation method, we systematically study the excitation and propagation of gravity waves and their effects on the dynamical structure of the middle and upper atmosphere. In the numerical studies, we focus on the influences of nonlinearity on the wave-energy transport. The numerical results show that: the characteristic time of the excitation of gravity wave by a tropospheric disturbance is approximately 2 times of wave period, and the energy conversion efficiency depends on the disturbance type; during the nonlinear propagation of gravity waves, their vertical wavelengths and frequencies are smaller then the prediction of linear gravity wave theory; the height variation of molecular viscosity coefficient will lead to the blockade of upward transport of gravity wave energy at the mesopause region, which brings us a new idea about the energy coupling mechanism of the mesosphere and the upper atmosphere; the saturation of gravity waves are mainly caused by the overturning of potential temperature, and the wave breaking, convection with smaller scales and turbulences are essentially only subsequent results. Accept above, we founded fully nonlinear 3-dimensional numerical model for the global middle and upper atmosphere, which is unique in the world

建立一个实用的数值模型，对具有不同背景风场、背景温场、耗散、扰动尺度、扰动振幅的重力波波包在平流层、中层的非线性传播过程进行数值模拟。探明在可压大气中多种因素作用下重力波的能量传输规律，对中层大气的动力学结构和普适谱的形成提供一个合理的解释，深入了解中层大气对对流层振动的响应和各层区之间的能量耦合过程。