基本流场切变对赤道长Rossby波的影响

INFLUENCE OF THE SHEARED BASIC FLOWS ON LONG EQUATORIAL ROSSBY WAVES

中文关键词:  赤道Rossby波  不稳定性  大气波动

英文关键词:Equatorial rossby waves  Instability  Atmosphere wave

中文摘要:

      文中应用赤道β平面近似,建立一个简单的斜压大气半地转模式,在热力学方程中引入表征基本位温场(θ)经向分布特征的无量纲参数σ,对线性化的扰动方程进行了频率分析,研究基本位温场经向非均匀分布以及基本气流垂直切变对赤道纬向超长尺度Rossby波动的影响,并指出仅考虑基本气流垂直切变或者基本位温场变化的作用是不合适的。定性分析结果表明:基本位温场经向温差必然有基本气流垂直切变与其相匹配,而基本气流垂直切变将导致赤道长Rossby波动不稳定并影响其纬向传播速度。

英文摘要:

      A simple baroclinic semi-geostrophic model on an equatorial β-plane is employed the effects of the vertical shearof the basic zonal geostrophic flow and the variation of the basic potential temperature on the longequatorial Rossby waves.Adimensionless parameter σ is introduced to represent the variation of basic potintial temperature field, in the thermody namics equation.Theoretical analyses show that the vertical shearof the basic flow will cause instability of the longequatorial Rossby waves and affectthe po pagation speed of the Rossby waves.