Beyond bulk entrainment and detrainment rates: A new framework for diagnosing mixing in cumulus convection

Abstract

A new framework for diagnosing mixing in cumulus convection is proposed, where the vertical evolution of the cloud mass flux distribution as a function of given parcel properties is viewed as a mapping process. Matrices that characterize this mapping process are constructed using a Lagrangian particle dispersion model embedded in a Large Eddy Simulation. Extending previous use of LES-diagnosed bulk entrainment and detrainment rates to test bulk plume models, the construction of these mapping matrices from LES provides a reference, against which multiple-parcel models can be compared. The framework is further applied to diagnose the response of shallow cumuli to a small temperature perturbation. Citation: Nie, J., and Z. Kuang (2012), Beyond bulk entrainment and detrainment rates: A new framework for diagnosing mixing in cumulus convection, Geophys. Res. Lett., 39, L21803, doi: 10.1029/2012GL053992.