The parallel scalability of the spectral transform method

Analytic and empirical studies are presented that allow the parallel performance, and hence the scalability, of the spectral transform method to be quantified on different parallel computer architectures. Both the shallow-water equations and complete GCMs are considered. Results indicate that for the shallow-water equations, parallel efficiency is generally poor because of high communication requirements. It is predicted that for complete global climate models, the parallel efficiency will be significantly better; nevertheless, projected teraflop computers will have difficulty achieving accpetable throughput necessary for long-term regional climate studies. -from Authors