A Quasi-one-Dimensional Cumulus Cloud Model and Parameterization of Cumulus Heating and Mixing Effects

Abstract

Abstract The characteristic properties of cumulus convection are investigated using a semi-one-dimensional, axisymmetric, quasi-Lagrangian steady-state model which takes into consideration the influence of the pressure perturbation, density stratification and nearby moist downdraft under two different environmental situations: 1) a potentially more unstable tropical environment and 2) a less unstable middle-latitude environment with prominent stable layers in the middle troposphere. It is found that the compressional heating of the dry environment makes the cloud air warmer and reduces the updraft velocity slightly, and moist downdraft cools the cloud air and reduces both the updraft and the cloud depth, while the influence of pressure perturbation also reduces the updraft but it is effective only for clouds of radii >1000 m. The influence of density stratification is to reduce wc, slightly at low levels and augment wc, at high levels and to slightly increase the cloud depth. The calculated precipitation ...