COMPUTATIONAL DESIGN OF THE NCAR COMMUNITY CLIMATE MODEL

An overview of the computational design for the latest version of the NCAR Atmospheric General Circulation Model, designated CCM2, is presented. Parallel implementation details are driven by two major algorithmic classes of computation that require different patterns of data communication, the spectral transform method and the semi-lagrangian advection technique. The organization and performance characteristics of a shared-memory parallel implementation, and an analogous distributed-memory message-passing parallel implementation are described. The advantages and limitations of this coarse-grained partitioning are discussed in the context of global climate modeling research.