# Convective richardson number

From AMS Glossary

## convective Richardson number

A dimensionless number that contains factors similar to the bulk Richardson number, but where the velocities, temperatures, and depths are based on mixed-layer scaling parameters.

The convective Richardson number Ri* can be written as where

*g*is gravitational acceleration, Δ_{EZ}θ_{v}is the change of virtual potential temperature across the depth of the entrainment zone,*z*_{i}is the depth of the mixed layer, θ_{v}is the average virtual potential temperature within the mixed layer, and*w*_{*}is the Deardorff velocity. The depth of the entrainment zone, and the entrainment rate, are related to this convective Richardson number.Nelson, E., R. Stull, and E. Eloranta 1989. A prognostic relationship for entrainment zone thickness. J. Appl. Meteor.. 28. 885–903.