In atmospheric dynamics and oceanography, the Rossby radius of deformation is the length scale at which rotational effects become as important as buoyancy effects in the evolution of the flow about some disturbance.

$L\_\{R\}\; \backslash equiv\; \backslash frac\{NH\}\{f\_\{0\}\}$, where $N$ is the Brunt-Väisälä frequency, $H$ is the scale height, and $f\_\{o\}$ is the Coriolis parameter at some latitude.