半地转近似下的非线性波

本文应用半地转的概念分析和求解了正压和斜压的大气运动。指出:(1)在水平无辐散或准地转条件下求单波解无法表现非线性作用的困难,可以应用半地转的假定来解决。为了避开上述困难,不得已仅保留部分非线性项,但为了准确表征大尺度运动,最好应用半地转假定,保留全部非线性项。(2)准地转的假定可以滤去快速波动,半地转的假定同样也可以滤去快速波动,而且半地转条件下的Rossby波具有充分的非线性特征。所以,它为讨论非线性问题提供了一个途径。

NONLINEAR WAVES WITH SEMI-GEOSTROPHIC FIOW

In this paper, we apply the semi-geostrophic approximation (or the geostropic momentum approximation) to analyse and solve the barotropic and baroclinic atmospheric motion. It is shown that the horizontal nondivergent or quasi-geostrophic approximation can not reflect the nonlinear effect. The semigeostrophic approximation can not only filter out the inertial gravity waves as the quasi-geostrophic approximation, but also find the solution of the nonlinear equations. The Rossby waves obtained by the semi-geostrophic approximation possess the nonlinear characterization. The semigeostrophic approximation provides the ways to discuss the nonlinear problem.