考虑β变化下的Rossby波

Rossby Waves with the Change of β

本文考虑了Rossby参数β随纬度的变化并引进了γ参数γ≡-dβ/dy=2Ωsin(?)/a^2.同时把β平面近似扩展为含γ参数的近似:f=f_0+β_0y-γ_0y^2/2.这就更接近实际,特特是在较高纬度地区.本文着重研究了γ参数对Rossby波的作用.研究指出:γ参数在较高纬地区有较强的作用.它可以形成纯γ参数所产生的Rossby波,并给出了在一般情况下的包含β变化的Rossby波相速公式,它在γ_0=0时退化为著名的Rossby公式.研究还指出:考虑了β的变化,即便基本气流(?)是y的线性函数也可以出现不稳定,但γ参数通常对Rossby波起稳定的作用.而且,它影响Rossby波的经向尺度和等位相线的结构,但都减缓Rossby波的增长或衰减.

In this paper, the change of the Rossby parameter ft with latitude is considered and the parameter is introduced and the -plane approxi- mamation is extended into which includes the parameter r. Such approximation closes further to practice especially in the high latitude regions. We give emphasis to the research of the effect of the parameter r on the Rossby waves. It is seen that the effect of the parameter r is remarkable in the high-latitude regions. It can produce the Rossby waves caused by the pure parameter V. And the phase speed formula of Rossby waves with the change of is generally given, which is degenerated into the well-known Rossby formula when r0=0. The researches also point out that when the change of is regarded, even if the basic current u is a linear function of y the unstable modes can also take place. However, the parameter r usually plays a stable part in the Rossby waves and it does affect the longitudinal scale and the structure of constant phase lines (trough-ridge lines) of Rossby waves and slow down the growing or decaying of Rossby waves.