Trajectory analysis of the propagation of Rossby waves on the Earth's δ-surface

本文通过迹线分析δ-平面近似下Rossby波传播的物理机制,结果表明:一方面,在正压大气和斜压大气模式下,通过位涡方程研究发现δ效应对Rossby波传播起到稳定的作用,特别在中高纬度其作用尤为明显;另外,利用WKB方法得到δ-平面近似下正压和斜压Rossby波色散关系说明了δ效应使Rossby波的移动速度增加。另一方面,在行波变换下通过迹线分析发现δ效应对正压和斜压Rossby波传播有着重要的影响。这些结果从理论上揭示了δ-平面近似下不论正压大气模式还是斜压大气模式δ效应对Rossby波作用的重要性不能忽视,为有助于进一步认识和探究Rossby波的演变提供详实的理论依据。

The propagation of Rossby waves on the Earth’s δ-surface is discussed in a reference frame propagation with the zonal phase speed of the wave.In this reference frame,trajectories and streamlines coincide;the propagation of Rossby waves has a different interpretation than in a reference frame fixed on the ground;and the mechanism for the propagation of Rossby waves depends not only on the different positions of the wave relative to the basic current,but also the variation ofβwith latitude(called theδ-effect).