| Astrophysics (Index) | About |
The Rossby radius of deformation is the length scale at which rotational effects are as significant as buoyancy or gravity waves. This gives some idea (regarding weather or ocean phenomena), based upon the phenomenon's size, whether rotation (e.g., Earth rotation) needs consideration. The radius is significant for atmospheres and oceans, and arises in astrophysics in regard to disks. The associated dimensionless parameter is the Rossby number.
If you quickly dumped some water at a single spot within a large pool, it would cause outward movement and waves. In a sufficiently large body of water like the (rotating) Earth's ocean, after some outward distance, the Coriolis force will have turned the water's movement ninety degrees so it is no longer moving outward, the distance until this happens being the Rossby radius of deformation, which depends (in this case) upon the Earth's gravitational acceleration, the water depth, and the "degree" of coriolis force at that point, which on the Earth's surface, depends upon latitude.