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Abstract

We present a distributed memory message passing parallel implementation of a finite-volume discretization of the primitive equations in the Community Atmosphere Model. Due to the data dependences resulting from the polar singularity of the latitude-longitude coordinate system, we employ two separate domain decompositions within the dynamical core: one in latitude/level space and the other in longitude/latitude space. This requires that the data be periodically redistributed between these two decompositions. In addition, the domains contain halo regions that cover the nearest-neighbor data dependences. A combination of several techniques, such as one-sided communication and multithreading, are presented to optimize data movements. The resulting algorithm is shown to scale to very large machine configurations, even for relatively coarse resolutions.

Keywords

atmospheric dynamics parallel processing

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References

Arakawa, A. and Lamb, V. 1977. Computational design of the basic dynamical processes of the UCLA general circulation model . Methods in Computational Physics 17: 173-265 .

Collins, W. D. et al. 2004. Description of the NCAR Community Atmosphere Model (CAM 3.0). NCAR Technical Note NCAR/TN-464+STR. NCAR, Boulder, CO .

Dagum, L. and Menon, R. 1998. OpenMP: an industry-standard API for shared-memory programming . IEEE Transactions on Computational Science and Engineering 5(1): 46-55 .

Drake, J. , Foster, I. , Michalakes, J. , Toonen, B. , and Worley, P. 1995. Design and performance of a scalable parallel community climate model . Parallel Computing 21(10): 1571-1591 .

Lin, S-J. 2004. A “vertically Lagrangian” finite-volume dynamical core for global models . Monthly Weather Review 132(10): 2293-2307 .

Lin, S-J. and Rood, R. 1996. Multidimensional flux form semi-Lagrangian transport schemes . Monthly Weather Review 124: 2046-2070 .

Lin, S-J. and Rood, R. 1997. An explicit flux-form semiLagrangian shallow-water model on the sphere . Quarterly Journal of the Royal Meteorological Society 123: 2477-2498 .

Putman, W. M. , Lin, S-J. , and Shen, B. 2005. Cross-platform performance of a portable communication module and the NASA finite volume general circulation model . International Journal of High Performance Computing Applications 19(3).

Rancic, M. , Purser, R. J. , and Mesinger, F. 1996. A global shallow-water model using an expanded spherical cube: gnomic versus conformal coordinates . Quarterly Journal of the Royal Meteorological Society 122: 959-982 .

10.

Sawyer, W. B. 1999. A multilevel parallel implementation of the Lin-Rood dynamical core . Proceedings of the 8th Workshop on the Solution of PDEs on a Sphere, San Francisco, CA.

11.

Sawyer, W. B. and Messmer, P. 2002. Parallel grid manipulations for general circulation models . Parallel Processing and Applied Mathematics: 4th International Conference, Naleczow, Poland, September 9-12, 2001, R. Wyrzykowski et al. , editors, Springer-Verlag, Berlin, pp. 564-571 .

12.

Wehner, M. F. , Mirin, A. A. , Eltgroth, P. G. , Dannevik, W. , Mechoso, C. R. , Farrara, J. , and Spahr, J. 1995. Performance of a distributed memory finite difference atmospheric general circulation model . Parallel Computing 21: 1655-1675 .