On steady- state one- dimensional models of cumulus convection

Abstract

A critical examination is undertaken of current steady- state one- dimensional cloud models which postulate lateral entrainment. It is found that such models cannot simultaneously predict values of liquid water content and cloud depth which are in agreement with observations. It is suggested that the success claimed for these models is based on a choice of arbitrary constants which may be valid only for a limited range of atmospheric conditions; in other conditions, predictions from the model may be seriously in error. In addition, since the physical basis of these models is invalid, there is no way of knowing what conditions are most important or how to avoid the ne%cessity of selecting fresh constants by trial and error with each fresh use of the model.