Performance of a spectral element atmospheric model (SEAM) on the HP Exemplar SPP2000

We describe the performance of a Spectral Element Atmospheric Model (SEAM) on the HP Exemplar SPP2000. SEAM uses spectral elements in the horizontal directions and sigma coordinates in the vertical. The model is both spectrally accurate, as demonstrated by a variety of test cases, and is well suited for modern distributed-shared memory computers, as demonstrated by the fact that we achieve 24 GFlops on a 240 processor HP Exemplar. More important to climate modelers, a 64 processor Exemplar can integrate a 20 level, 160 km resolution SEAM dynamical core at a rate of 3.6 wall clock hours per model year. SEAM is portable and is implemented in FORTRAN 77 with message passing calls.