Evaluation of parametric assumptions for shallow cumulus convection

Abstract

A large-eddy simulation (LES) model has been utilized to study nonprecipitating shallow convective clouds such as observed during the undisturbed BOMEX period in the trade wind areas. The authors have been able to simulate shallow convective clouds under quasi-steady state conditions over a long period of 7 hours. This is a necessary condition to investigate diagnostic cumulus parameterization schemes since such schemes usually assume steady-state conditions. In addition, the LES model delivers detailed information concerning the dynamics of shallow convective clouds. This is used to verify basic parameterizations of turbulent fluxes and entrainment and detrainment rates used in large-scale models. -from Authors