# Ekman number

From AMS Glossary

## Ekman number

Explicitly, the vertical Ekman number is in which in which

*K*_{v}is the vertical eddy viscosity,*f*the Coriolis parameter, and*D*the characteristic vertical length scale. The horizontal Ekman number is*K*_{h}is the horizontal eddy viscosity and*L*is the characteristic horizontal length scale. The Ekman number gives a measure of the rate at which stresses at a boundary (e.g., wind-induced stresses at the ocean surface) are communicated to the fluid interior.