ROSSBY WAVES WITH THE CHANGE OF β |
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摘 要: | In this paper, the change of the Rossby parameter β with latitude is considered and the parameter γ≡-dβ/dy=2sinφ/a2 is introduced and the β-plane approximation is extended into f=f0+β0y-γ0y2/2 which includes the parameter γ. Such approximation closes further to practice especially in the high latitude regions.We give emphasis to the research of the effect of the parameter γ on the Rossby waves. It is seen that the effect of the parameter γ is remarkable in the high latitude regions. It can produce the Rossby waves caused by the pure parameter γ. And the phase speed formula of Rossby waves with the change of ft is generally given, which is degenerated into the well-known Rossby formula when γ0=0. The researches also point out that when the change of β is regarded, even if the basic current u is a linear function of y the unstable modes can also take place. However,the parameter γ 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.
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关 键 词: | Rossby waves Rossby parameter parameter γ |
收稿时间: | 4 March 1991 |
Rossby waves with the change of β |
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Authors: | Liu Shi-kuo Tan Ben-kui |
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Institution: | (1) Dept. of Geophysics, Peking University, Beijing;(2) Dept. of Atmospheric Sciences, Nanjing University, Nanjing |
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Abstract: | In this paper, the change of the Rossby parameter β with latitude is considered and the parameter γ≡−dβ/dy=2Ωsinϕ/a2 is introduced and the β-plane approximation is extended into f=f0+β0y-Y0y2/2 which includes the parameter γ. Such approximation closes further to practice especially in the high latitude regions.
We give emphasis to the research of the effect of the parameter γ on the Rossby waves. It is seen that the effect of the parameter
γ is remarkable in the high latitude regions. It can produce the Rossby waves caused by the pure parameter γ. And the phase
speed formula of Rossby waves with the change of β is generally given, which is degenerated into the well-known Rossby formula
when Y0=0. The researches also point out that when the change of β is regarded, even if the basic current ū is a linear function
of y the unstable modes can also take place. However, the parameter γ 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. |
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Keywords: | Rossby waves Rossby parameter parameter γ |
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