The Rossby Number (Ro) is a dimensionless number consisting of the ratio of internal to Coriolis Force. It is used in modeling Atmosphere and ocean dynamics. It is defined as:
Ro = U / Lf
The Convective Rossby Number, of interest in the study of convection in stars and planets and the resulting Dynamos, is the ratio of a buoyancy force to the Coriolis force.