High Resolution Mesh Convergence Properties and Parallel Efficiency of a Spectral Element Atmospheric

• Main Authors: Dynamical Core, John Dennis, Aimé Fournier, William F. Spotz, Amik St. -cyr, Mark A. Taylor, Steve Thomas, Henry Tufo
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: polar night
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.118.4485; http://www.csc.cs.colorado.edu/~tufo/pubs/tufo-2004-ijhpca.pdf

We first demonstrate the parallel performance of the dynamical core of a spectral element atmospheric model. The model uses continuous Galerkin spectral elements to discretize the surface of the Earth, coupled with finite differences in the radial direction. Results are presented from two distributed memory, mesh interconnect supercomputers (ASCI Red and BlueGene/L), using a two-dimensional space filling curve domain decomposition. Better than 80 % parallel efficiency is obtained for fixed grids on up to 8938 processors. These runs represent the largest processor counts ever achieved for a geophysical application. They show that the upcoming Red Storm and BlueGene/L supercomputers are well suited for performing global atmospheric simulations with a 10km average grid spacing. We then demonstrate the accuracy of the method by performing a full 3D mesh refinement convergence study, using the primitive equations to model breaking Rossby waves on the polar night vortex. Due to the excellent parallel performance, the model is run at several resolutions up