切变基本纬向流中非线性赤道Rossby长波

NONLINEAR EQUATORIAL ROSSBY LONG WAVES IN A SHEAR FLOW

为了解决观测和理论研究中的一些问题以及更好地了解热带大气动力学 ,有必要进一步研究基本气流的变化对大气中赤道Rossby波动的影响 .本文研究分析基本气流对赤道Rossby长波的影响 ,利用一个简单赤道 β平面浅水模式和摄动法 ,研究纬向基本气流切变中非线性赤道Rossby波 ,推导出在切变基本纬向流中赤道Rossby长波振幅演变所满足的非线性KdV方程并得到其孤立波解 .分析表明 ,孤立波存在的必要条件是基本气流有切变 ,而且基流切变不能太强 ,否则将产生正压不稳定 .

In order to tackle the questions arising from the observations and theoretical studies, and to better understand tropical atmospheric dynamics, it is necessary to investigate further the effects of the varying basic states of the atmosphere upon the equatorial trapped nonlinear Rossby waves. The purpose of this study is to examine the effects of basic zonal flows on the equatorial Rossby long waves. A simple shallow water model on an equatorial β plane is employed to investigate the nonlinear equatorial Rossby waves in a mean zonal flow with meridional shear by the standard reductive perturbation method. The nonlinear Korteweg de Vries (KdV) equation, satisfied by the nonlinear equatorial Rossby long waves of small amplitude, is derived. The analyses indicate that a necessary condition of the soliton formation is the basic flow with shear, and the shear is not so strong as to create barotropic instability. [