Porting the Quasi-Nonhydrostatic Meteorological Model to the Kendall Square Research KSR1

The Forecast Systems Laboratory is currently developing and testing weather models on various parallel computers with a view toward ultimate production use. As part of that effort we have ported a “Quasi-Nonhydrostatic” Meteorological Model to the Kendall Square Research KSR1 parallel supercomputer. The porting was done in three stages: first the original sequential code was made efficient on one processor, then the code was parallelized using “tiling” directives, and lastly the parallel code was optimized. We describe this process in some detail and report the resulting performances.