Performance of a three dimensional hydrodynamic model on a range of parallel computers

A three dimensional shallow sea model is briefly described in which the three dimensional flow field in a shallow sea region is represented using a finite difference grid in the horizontal and a spectral expansion in the vertical. A horizontal domain decomposition is employed, in which each processor works on a patch of sea and communicates boundary values with neighbouring processors as required. Performance characteristics of this code are presented using computers with a range of parallel architectures, including shared memory vector-parallel, distributed memory message passing, and data parallel. Whereas good parallel efficiency is readily obtained, the performance on most highly parallel computers is limited by the performance of the individual processors