Partitioning mass, heat, and moisture budgets of explicitly simulated cumulus ensembles into convective and stratiform components

Abstract

Simulated data from the UCLA Cumulus Ensemble Model (CEM) are analyzed to partition mass, heat, and moisture budgets of cumulus ensembles into convective and stratiform components. A method based primarily on the horizontal distribution of maximum cloud draft strength below the melting level in a CEM grid column has been developed for this analysis. The importance of the convergences of eddy fluxes, especially in the moisture budget, is confirmed. The convergences in the stratiform component are found to be parameterizable only if the vertical motions and the properties of both mesoscale updrafts and mesoscale downdrafts are known. The horizontal inhomogenity within mesoscale updrafts/downdrafts is of secondary importance for parameterizing the convergences of eddy fluxes in the stratiform component. -from Author