Parallel computation in atmospheric chemical modeling

The porting of atmospheric chemical dynamic models to massively parallel computers presents interesting computational challenges. Strategies for the parallelization of the transport and chemistry operators of atmospheric models are outlined. The use of parallel buffers to perform input/output operations is described. Results are given for implementation of the CIT urban air pollution model on distributed memory multiple instruction/multiple data (MIMD) machines ranging from a cluster of workstations to a 512 node Intel Paragon. A speed-up factor of 94.9 is achieved when the I/O, transport, and chemistry portions of the model are performed in parallel using 256 nodes of the Intel Paragon.