A diagnostic model of turbulent transport in a cumulus cloud layer

Results are presented from a mixed-layer model which has been used to diagnose the average turbulent flux profiles in cumulus-capped boundary-layers. The model makes use of separate mixed layer models for the clear and cloudy parts of the broken cloud layer. It is shown, by comparison with aircraft observations, that the model can be applied to estimate the area-averaged flux profiles under conditions in which the clouds penetrate the capping inversion. It is also shown that a small but significant part of the vertical transport results from the displacement of air from above the inversion around the growing clouds.