Parallelization and distribution of a coupled atmosphere-ocean general circulation model

Abstract

First, the domains of both the gridpoint AGCM and OGCM are divided into subdomains for which calculations are carried out concurrently (domain decomposition). Second, the model is decomposed based on the diversity of tasks performed by its major components (task decomposition). Three such components are identified: a) AGCM/physics, which computes the effects on the grid-scale flow of subgrid-scale processes such as convection and turbulent mixing; b) AGCM/dynamics, which computes the evolution of the flow governed by the primitive equations; and c) the OGCM. Task decomposition allows the AGCM/dynamics and OGCM calculations to be carried out concurrently. Last, computation and communication are organized in such a way that the exchange of data between different tasks is carried out in subdomains of the model domain (I/O decomposition). In a dedicated computer network environment, the wall-clock time required by the resulting distributed application is reduced to that for the AGCM/physics, with the other two components and interprocess communications running in parallel. -from Authors