SciDAC-CCPP

Program Web sites:

http://www.scidac.org/climate.html
http://www.er.doe.gov/production/ober/CCRD/model.html

Team Members:

Henry Tufo (PI, CU/NCAR), http://csc.cs.colorado.edu/~tufo
Ram Nair (Co-I, NCAR), http://www.scd.ucar.edu/css/staff/rnair
Phil Rasch (Co-I, NCAR), http://www.cgd.ucar.edu/cms/pjr
Van Cheruvu (Postdoc, CU)
Hae-Won Choi (Postdoc, CU)
Mike Levy (Graduate Student, CU)
Theron Voran (Graduate Student, CU)
Michael Oberg (Undergraduate Student, CU)
Brandon Werdel (Undergraduate Student, CU)

Improved Transport Processes for CCSM

R.D. Nair, P.J. Rasch, and H.M. Tufo

The goal of this project is to develop a scalable conservative dynamical core for CCSM that addresses atmospheric transport issues such as mass conservation and monotonicity preservation. Our starting point is a high-order inherently conservative shallow water model based on the discontinuous Galerkin (DG) method (Nair et al. 2004, Mon. Wea. Rev.) for the cubed-sphere. To reduce development costs we will integrate this model into the NCAR high-order multiscale modeling environment (HOMME) as this contains a 3D dynamical core based on the continuous Galerkin method which efficiently scales to thousands of processors. However, there are several issues remaining. Extending the model to a conservative 3D dynamical core requires that the low-order finite-difference approach employed in HOMME for the vertical discretization be replaced. One promising approach is high-order Lagrangian vertical advection methods based on conservative remapping. Another issue is achieving high integration rates. For this we consider implicit/semi-implicit and OIF schemes (St-Cyr and Thomas, (2004), Appl. Num. Math.). Finally, we need to determine whether this core is suitable for climate simulations and its computational efficiency. We will leverage work currently underway with IBM and Sandia National Laboratories to integrate CAM and CRCP physics into HOMME for AMIP and Aquaplanet simulations on the IBM BlueGene/L and Cray Red Storm platforms.

Talks

Towards an Efficient and Scalable Discontinuous Galerkin Atmospheric Model, 19th IEEE International Parallel & Distributed Processing Symposium, Denver, Colorado, April 8, 2005. [PDF]

Papers

H.-W. Choi, R.D. Nair, H.M. Tufo, A scalable high-order Discontinuous Galerkin methods for global atmospheric modeling. Proceedings of International Conference on Parallel Computational Fluid Dynamics (Parallel CFD 2006). 8 pages, Under review.

Choi, H-W., R. D. Nair and H. M. Tufo, 2006: A scalable high-order discontinuous Galerkin method for global atmosperic modeling. Parallel CFD 2006, Busan, South Korea.

Nair, R.D. and H.~M. Tufo, 2006: A scalable High-Order Dynamical Core for Climate Modeling. Proceedings of International Conference on Mesoscale Process in Atmosphere, Ocean and Environment Systems. IMPA 2006, Feb. 14th-17th, IITD, New Delhi, India.

Dennis, J.M., R.D. Nair, H.M. Tufo, M. Levy, and T. Voran, 2006: Development of a Scalable Global Discontinuous Galerkin Atmospheric Model. Int. J. of Comput. Sci. Eng., in press.

J.M. Dennis, M. Levy, R.D. Nair, H.M. Tufo, and T. Voran. Towards an Efficient and Scalable Discontinuous Galerkin Atmospheric Model., proceedings of the 19th IEEE International Parallel & Distributed Processing Symposium, 2005. Abstract [PDF] Paper [PDF]

Ramachandran D. Nair, Stephen J. Thomas, and Richard D. Loft. A Discontinuous Galerkin Transport Scheme on the Cubed Sphere. Monthly Weather Review: Vol. 133, No. 4, pp. 814-828. April 2005. [PDF]

Ramachandran D. Nair, Stephen J. Thomas, and Richard D. Loft. A Discontinuous Galerkin Global Shallow Water Model. Monthly Weather Review: Vol. 133, No. 4, pp. 876-888. April 2005. [PDF]