Petascale atmospheric models for the Community Climate System Model: new developments and evaluation of scalable dynamical cores

We present results from the integration and evaluation of the spectral finite-element method into the atmospheric component of the Community Climate System Model (CCSM). This method overcomes the atmospheric scalability bottleneck by allowing the use of a true two-dimensional domain decomposition for the first time in the CCSM. Scalability is demonstrated out to 86,200 processors with an average grid spacing of 0.25? (25 km). We present initial evaluations results using a standardized test problem with the full suite of CCSM atmospheric model forcings and subgrid parametrizations but without the CCSM land, ice, or ocean models. For this realistic setting, the true solution is unknown. Even convergence under mesh refinement is not expected, so we cannot rely on high-resolution reference solutions. Instead we focus on intermodel comparisons and use the Williamson equivalent resolution methodology to evaluate the results.

[1]  A. Simmons,et al.  An Energy and Angular-Momentum Conserving Vertical Finite-Difference Scheme and Hybrid Vertical Coordinates , 1981 .

[2]  Stephen J. Thomas,et al.  The NCAR Spectral Element Climate Dynamical Core: Semi-Implicit Eulerian Formulation , 2005, J. Sci. Comput..

[3]  A. N. Other.  A demonstration of the L A T E X2ε class file for the International Journal for Numerical Methods in Fluids , 2010 .

[4]  Hsien-Wang Ou.  Dynamics of Atmospheres and Oceans , 2010 .

[5]  Dale B. Haidvogel,et al.  Wind driven general circulation of the Mediterranean Sea simulated with a Spectral Element Ocean Model , 2002 .

[6]  David L. Williamson,et al.  Time-Split versus Process-Split Coupling of Parameterizations and Dynamical Core , 2002 .

[7]  Christopher Edwards,et al.  Multi-scale geophysical modeling using the spectral element method , 2002, Comput. Sci. Eng..

[8]  M. Taylor.  The Spectral Element Method for the Shallow Water Equations on the Sphere , 1997 .

[9]  Stephen J. Thomas,et al.  Semi-Implicit Spectral Element Atmospheric Model , 2002, J. Sci. Comput..

[10]  Gregory Bryan.  Computing in Science and Engineering , 1999, IEEE Software.

[11]  W. Collins,et al.  Description of the NCAR Community Atmosphere Model (CAM 3.0) , 2004 .

[12]  Mark A. Taylor,et al.  Global Modelling of the Ocean and Atmosphere Using the Spectral Element Method , 1997 .

[13]  M. Suárez,et al.  A proposal for the intercomparison of the dynamical cores of atmospheric general circulation models , 1994 .

[14]  R. D. Ward.  MONTHLY WEATHER REVIEW. , 1907, Science.

[15]  Stephen J. Thomas,et al.  A mass and energy conserving spectral element atmospheric dynamical core on the cubed-sphere grid , 2007 .

[16]  Aimé Fournier,et al.  A Spectral Element Version of CAM2 , 2007 .

[17]  Patrick H. Worley,et al.  Performance Portability in the Physical Parameterizations of the Community Atmospheric Model , 2005, Int. J. High Perform. Comput. Appl..

[18]  Francis X. Giraldo,et al.  A spectral element shallow water model on spherical geodesic grids , 2001 .

[19]  D. Williamson,et al.  A baroclinic instability test case for atmospheric model dynamical cores , 2006 .

[20]  The International Journal of High Performance Computing Applications— , 1998 .