Introduction

Abstract

It is an understatement to say convection is important in global climate. Its representation in GCMs is the single most difficult task among all physical processes. In this talk, I will discuss several longstanding model issues related to convection in all versions of the NCAR CAM and CCSM family, including MJO and ITCZ. I will also discuss some recent effort to include microphysics in convection parameterization. MJO simulation can be improved in the NCAR models by modifying convection parameterization, but we have not fully understood its mechanism. This talk will show that coordinated interaction between shallow and deep convection is a key factor. For ITCZ, the formation of double ITCZ in GCMs involves a chain of complex interaction of atmosphere and ocean. Convection plays a central role in this interaction chain, and ITCZ simulation can be improved if convection representation is improved. For convection microphysics, I will show that a detailed representation of microphysical processes in convective precipitation can have important impact on large-scale cloud water budget.