Abstract: Characteristics of non-linear mountain gravity waves and atmospheric ship waves generated by three-dimensional multi-layer flow over an isolated mountain were investigated using the numerical model, ARPS. Results show that the transverse and diverging modes of atmospheric ship waves generated by two layer flow over an isolated mountain are the same as that of mountain gravity waves in linear models. However, non-linear mountain gravity waves and atmospheric ship waves generated by three-dimensional three-layer flow over an isolated mountain show completely different characteristics from linear mountain gravity waves. In the nonlinear case, due to non-linear interactions there exist two ship waves involving in two diverging modes on the lee side, which propagate downstream. These ship wave modes have more complex wave characteristics compared with that in two layer and linear models.

Key words: mountain gravity waves, multi-layered model, atmospheric ship waves, diverging waves, transverse waves

摘要： 利用中尺度数值模式ARPS研究了分层流动大气中的非线性山脉重力波。分层流动过孤立山脉所产生的山脉重力波的数值模拟表明，具有两层模式结构的气流过孤立山脉产生一个发散模态的拦截背风波，同线性理论模式计算结果具有基本相同的流动特征。但是具有三层模式结构的气流过孤立山脉所产生的非线性山脉重力波和大气船波表现出同两层模式结构的气流完全不同的流动特征，因非线性相互作用在山脉背风面产生了2个发散波模态的拦截背风波向山脉下游传播，具有同两层模式和线性理论模式相比更加复杂的波动特征。

关键词: 山脉重力波, 多层模式, 大气船波, 发散模态, 拦截模态