A parameterization of cloud microphysics for long-term cloud-resolving modeling of tropical convection

This paper documents development of a simple cloud microphysical parameteri zation for use in long-term cloud-resolving simulations of maritime tropica l convection. The parameterization is based on the bulk approach and consid ers two classes of liquid water (cloud water and rain) and two classes of i ce (slowly falling ice A and fast-falling ice B). Ice A represents unrimed or lightly rimed ice particles whose spectral characteristics are assumed t o follow aircraft observations in tropical upper-tropospheric anvil clouds. Ice B, on the other hand, represents heavily rimed ice particles (e.g., gr aupel) which occur in the vicinity of convective towers. Mixing ratios for these four classes of cloud condensate are used as model variables. Togethe r with the mixing ratio for water vapor, five field variables are used to r epresent all forms of water in the tropical atmosphere. The parameterizatio n is used in a prescribed flow model to illustrate development of tropical convective and stratiform precipitation. Application of the parameterizatio n to the cloud-resolving simulations of cloud systems observed during the T OGA COARE field campaign is also presented. (C) 1999 Elsevier Science B.V. All rights reserved.