非纬向基本流上的斜压扰动  

Baroclinic Disturbances in Non-zonal Basic Flow

作　　者：林一骅 LIN Yihua(State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics(LASG),Institute of AtmosphericPhysics,Chinese Academy of Sciences,Beijing 100029;College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049)

机构地区：[1]中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室,北京100029 [2]中国科学院大学地球与行星科学学院,北京100049

出　　处：《大气科学》2024年第4期1357-1365,共9页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金项目42275057、42230403、42075008。

摘　　要：本文基于能量方法研究了时间平均的非纬向基本流的稳定性以及该基本流上斜压扰动的发展,并探讨了经向基本气流对于扰动发展的作用。从广义能量方程得到了时间平均的非纬向基本流的稳定性条件,并用扰动能量方程研究了正压发展(衰减)和斜压发展(衰减)的扰动结构及其与基本流的配置关系。研究发现,以急流轴为中心,对于正压发展的扰动,其流线在水平面上向基本气流来流方向的下游倾斜,而对于正压衰减的扰动,其流线在水平面上向基本气流来流方向的上游倾斜。对流层大气中,斜压发展的扰动,其流线在垂直剖面上随高度增加向基本气流来流方向的上游倾斜,而斜压衰减的扰动,其流线在垂直剖面上随高度增加向基本气流来流方向的下游倾斜。经向基本气流的存在会促进并加强扰动的发展,令扰动更加不稳定。The development of the baroclinic disturbance and stability of the time-averaged non-zonal basic flow in a baroclinic atmosphere are investigated by energy method.More attention is paid to the problems on the role of the meridional basic flow to the development of the disturbance.The sufficient condition for stability and the necessary condition for instability of the time-averaged non-zonal basic flow are obtained from the generalized energy equation.With the axis of jet stream as the center,for the barotropic developing(decaying)disturbance,the perturbation streamlines must be tilting(on average)towards the downstream(upstream)direction of the basic flow on the horizontal plane.In the troposphere,for the baroclinic developing(decaying)disturbance,the perturbation streamline must be sloping upward and tilting(on average)towards the upstream(downstream)direction of the basic flow on the vertical section.The existence of the meridional basic flow will promote and strengthen the development of the disturbance,making the developing disturbance more unstable.

关 键 词：非纬向基本流 稳定性 斜压扰动 发展 经向基本气流 

分 类 号：P401[天文地球—大气物理学与大气环境]