垂直切变流中非线性重力波及其相互作用

Nonlinear Gravitational Waves and Their Interactions in a Vertical Shearing Flow

利用多重尺度摄动法,推导出斜压大气中(基本风场具有垂直切变)两个非线性重力波相互作用方程,这两个方程联立组合为耦合非线性schrodinger方程组。两个重力波相互作用时可激发出重力驻波。数值计算表明:两个孤立重力波相遇,相追会使波振幅增大,波宽变窄。强烈对流天气突然爆发的可能原因之一是中尺度重力波非线性相互作用的结果。

In this paper,the nonlinear gravitational waves in a baroclinic atmosphere are studied.It is found by use of the WKB method that the interaction between two wave packets is governed by coupled nonlinear schrdinger equations and the immobile wave may occur.It is shown by numerical calculations that the waves amplify and the width of waves becomes narrow after the collision or chase of two solitary gravitational waves.The results indicate that the nonlinear interaction between the gravitational waves may be one of the causes for the outbreak of severe convective weather.