Prognostic evaluation of assumptions used by cumulus parameterizations

Abstract

Using a spectral-type cumulus parameterization that includes moist downdrafts within a three-dimensional mesoscale model, various disparate closure assumptions are systematically tested within the generalized framework. The dynamic control is the part that determines the modulation of the convection by the environment. It is shown that rate of destabilization, as well as instantaneous stability, work well for the dynamic control. Integrated moisture convergence leads to underprediction of rainfall rates and subsequent degrading of the results in terms of movement and structure of the mesoscale convective system (MCS). The feedback determines the modification of the environment by the convection, and in this study is considered together with the static control, which determines cloud properties. All feedback and static-control assumptions tested here seem very important for the prediction of sea level pressure and rainfall. -from Author