Performance of a distributed memory finite difference atmospheric general circulation model

A new version of the UCLA atmospheric general circulation model suitable for massively parallel computer architectures has been developed. This paper presents the principles for the code's design and examines performance on a variety of distributed memory computers. A two dimensional domain decomposition strategy is used to achieve parallelism and is implemented by message passing. This parallel algorithm is shown to scale favorably as the number of processors is increased. In the fastest configuration, performance roughly equivalent to that of multitasking vector supercomputers is achieved.