This Article Full Text (PDF) References Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Add to Saved Citations Download to citation manager Add to My Marked Citations Citing Articles Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Dennis, J. Articles by Tufo, H. Search for Related Content Social Bookmarking                   What's this?

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

Scientific Computing Division, National Center for Atmospheric Research, Boulder, CO, USA

Aimé Fournier

Department of Meteorology, College of Computer, Mathematical, Physical Sciences, University of Maryland at College Park, USA

William F. Spotz

Computation, Computers, Information and Mathematics, Sandia National Laboratories, Albuquerque, NM, USA

Amik St-Cyr

Scientific Computing Division, National Center for Atmospheric Research, Boulder, CO, USA

Mark A. Taylor

Computation, Computers, Information and Mathematics, Sandia National Laboratories, Albuquerque, NM, USA, mataylo{at}sandia.gov

Stephen J. Thomas

Scientific Computing Division, National Center for Atmospheric Research, Boulder, CO, USA

Henry Tufo

Scientific Computing Division, National Center for Atmospheric Research, Boulder, CO, USA

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 super-computers are well suited for performing global atmospheric simulations with a 10 km average grid spacing. We then demonstrate the accuracy of the method by performing a full three-dimensional mesh refinement convergence study, using the primitive equations to model breaking Rossby waves on the polar vortex. Due to the excellent parallel performance, the model is run at several resolutions up to 36 km with 200 levels using only modest computing resources. Isosurfaces of scaled potential vorticity exhibit complex dynamical features, e.g. a primary potential vorticity tongue, and a secondary instability causing roll-up into a ring of five smaller subvortices. As the resolution is increased, these features are shown to converge while potential vorticity gradients steepen.

Key Words: spectral elements • dynamical core • parallel scalability • mesh convergence • atmospheric circulation

CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?