波状扰动激发的重力波波包在中层大气中能量传播和转换特性的数值研究

采用谱配置方法对具有高斯分布的波状扰动激发重力波过程中的能量传播和转换特性进行数值研究．模拟结果表明：初始时刻单一的水平风、垂直风、密度或温度的波状扰动都可以激发出两支重力波波包，其中一文向上传播，而另一支则向下传播；在相同的波参数下，4种波状扰动所激发的重力波波包的能量传播路径几乎完全一致，与线性理论给出的射线路径却有些差异．进一步的数值分析则表明：4种波状扰动转化为波动的特征时间基本相等，约为2个波动周期，但是在这个转换过程中，不同扰动的能量转换效率却差别很大．

A NUMERICAL STUDY ON THE ENERGY PROPAGATION AND CONVERSION OF GRAVITY-WAVE PACKETS EXCITED BY WAVE-LIKE DISTERBANCE IN THE MESOSPHERE

By using the spectral allocation method, the characteristics of the energy propagation and conversion in the excitation of gravity wave by an initially given Gaussian wave-like disturbance is numerically studied. The simulation results show that any single wave-like disturbance component (horizontal wind, vertical wind, density or temperature) can independently excite two gravity-wave packets, one propagates upward and another propagates downward. With the same wave parameters, the energy propagation paths of the packets under the above mentioned four kinds of disturbances are almost identical with each other and slightly different from the ray paths derived by the linear theory. A further numerical analysis indicates that the characteristic time of the energy conversion from a disturbance to a wave is almost identical for those different disturbances, equal to two times of wave period. However, the energy conversion efficiencies for different disturbances depart significantly from each other.