Parallel computational design of NJR global climate models

Abstract

An overview of a parallel computational design for global climate models, called N JR, are described. The models consist of two atmospheric general circulation models: the spectral and grid point atmospheric model, and an ocean general circulation model. The spectral atmospheric model descritizes the equations by using orthogonal spherical harmonic function. The computation domain is decomposed into subdomains along latitudes so that FFT is calculated in parallel without data communication. The complete-data-exchange type of communication is performed after the FFT and Legendre transformation is executed in parallel along longitude without data communication. The grid point atmospheric model and the ocean circulation model employ finite-difference method. The computation domain is decomposed into subdomains along latitude and the boundary data of each subdomain are exchanged between neighboring subdomains in each time step. The N JR global climate model is run efficiently on high performance parallel computers.