This paper presents a diagnostic study of two models proposed by Betts (1973a). The first was a model for a well-mixed sub-cloud layer capped by a more stable transition layer. The downward heat flux at the base of this transition layer is here estimated from the thermal structure of the layer to be 15-25% of the surface sensible heat flux. The second model was a model for a two layer lapse-rate structure for the cumulus layer. A sensitivity analysis...

It is shown that a general class of nonlinear partial differential equations -- including those frequently used in predicting atmospheric motions -- can be converted to computational form by either the "finite difference" or "spectral" method to yield formally identical equations.