Comparison of shared memory and distributed memory parallelisation strategies for grid-based weather forecast models

We have parallelized a grid-based weather forecast model called SEQN using two programming models: shared memory and message passing. By shared memory we mean programming in standard Fortran 77 with directives for parallelism, such as is found on the Kendall Square Research KSR1 parallel supercomputer. For message passing we used the distributed memory Intel Paragon. We have benchmarked both versions of the code on the respective machines, and have run the message passing version on the KSR1 in order to directly compare performance and evaluate the cost of portability. In addition we present first results from the KSR2