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

ABSTRACT

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 of β with latitude (called the δ-effect).

摘要

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。

KEYWORDS:

• Trajectory
• Rossby waves
• β-plane
• δ-effect

关键词:

• 迹线
• Rossby波
• β-平面
• δ-平面

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This study was supported by the National Natural Science Foundation of China [grant numbers 11362012, 11562014, 41465002, and 41765004] and the High School Science Research Project of the Inner Mongolia Autonomous Region [grant number NJZY16096], the Natural Science Foundation of Inner Mongolia[grant number 2018LH04005].