A Unified Representation of Deep Moist Convection in Numerical Modeling of the Atmosphere. Part II

• Published in: Journal of the atmospheric sciences Vol. 71; no. 6; pp. 2089 - 2103
• Main Authors: Wu, Chien-Ming, Arakawa, Akio
• Format: Journal Article
• Language: English
• Published: Boston American Meteorological Society 01.06.2014
• Subjects: Atmosphere; Clouds; General circulation models; Meteorology; Physics; Variables
• ISSN: 0022-4928; 1520-0469
• DOI: 10.1175/JAS-D-13-0382.1

Abstract In Part I of this paper, a generalized modeling framework for representing deep moist convection was presented. The framework, called unified parameterization, effectively unifies the parameterizations in general circulation models (GCMs) and cloud-resolving models (CRMs) and thus is applicable to any horizontal resolution between those typically used in those models. The key parameter in the unification is the fractional convective cloudiness σ, which is the fractional area covered by convective updrafts in the grid cell. The central issue of Part I is to formulate the σ dependence of vertical eddy transports of thermodynamic variables and to determine σ for each realization of grid-scale processes. The present paper completes the formulation through further analysis of the simulated data. The analyzed fields include the vertical structure of the σ dependence of vertical and horizontal eddy transports of moist static energy and horizontal momentum and that of cloud microphysical sources. For the momentum transport, the analysis results clearly show the limits of the traditional approach of parameterization based on an effectively one-dimensional model. For cloud microphysical conversions, it is shown that those taking place primarily inside and outside the updrafts are roughly proportional to σ and 1 − σ, respectively.