Rossby radius of deformation
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In atmospheric dynamics and physical oceanography, the Rossby radius of deformation is the length scale at which rotational effects become as important as buoyancy or gravity wave effects in the evolution of the flow about some disturbance.
- , where is the gravitational acceleration, is the water depth, and is the Coriolis parameter at the reference latitude.
For f = 1×10−4 s−1 appropriate to 45° latitude, and D = 4 km, LR ≈ 2000 km; and for D = 40 m, LR ≈ 200 km.
The nth baroclinic Rossby radius is:
The ratio N/f0 is typically of order 100, so the Rossby radius is about 100 times the vertical scale height, H. For a vertical scale associated with the height of the tropopause, LR, 1 ≈ 1000 km, which is the predominant scale seen on weather charts for cyclones and anticyclones. This is commonly called the synoptic scale.
- Gill, A. E., 1982: Atmosphere-Ocean Dynamics, Academic Press, Orlando, 662 pp.