chapter  9
Exascale Programming Approaches for Accelerated Climate Modeling for Energy
ByMatthew R. Norman, Azamat Mametjanov, Mark Taylor
Pages 20

The Accelerated Climate Modeling for Energy (ACME) project model is composed of five main components: atmosphere, ocean, land surface, sea ice, and land ice. The atmospheric component, the community atmosphere model-spectral element (CAM-SE) is based on a local, time-explicit spectral element (SE) method on cubed-sphere topology with static adaptation capability. CAM-SE realizes spherical geometry by use of the so-called cubed-sphere grid, which in this case utilizes a nonorthogonal equal-angle gnomonic projection from a cube onto the sphere. The fact that the SE method at its core is essentially made up of 1-D sweeps of matrix-vector multiplies is advantageous for graphics processing units because this means that data fetched from dynamic random-access memory will be reused. For the sake of efficiency, the choice was made at the creation of CAM-SE to structure the OpenMP implementation using parallel regions instead of loop-level OpenMP.