High-Order Method Modeling Environment (HOMME)
The High-Order Method Modeling Environment (HOMME) is a framework, developed by the Computational and Information Systems Laboratory (CISL) at the National Center for Atmospheric Research (NCAR) in collaboration with the Sandia National Laboratory. The primary objective for this project is to investigate, using the high-order element-based numerical methods on the cubed-sphere, to build conservative and accurate atmospheric dynamical cores capable of efficiently scaling to hundreds of thousands of processors and achieve scientifically useful integration rates. Currently, HOMME employs the Spectral Element (SE) and the Discontinuous Galerkin (DG) methods on a cubed-sphere tiled with quadrilateral elements. HOMME can be configured to solve the shallow water or the dry/moist primitive equations, and has been shown to efficiently scale to O(100,000) processors.
In recent years HOMME has undergone several evolutionary cycles, aimed for extending HOMME to a framework capable of providing the atmospheric science community with a new generation of atmospheric general circulation models for the Community Earth Sysytem Model (CESM). HOMME provides monotonic and mass-conserving transport of multiple species, and easily couple to community physics packages such as Community Atmosphere Model (CAM) physics. Recently, the spectral-element variant of hydrostatic HOMME model has been adopted as the default dynamical core in CAM, and also known as the NCAR CAM-SE. Achieving these objectives will allow climate scientists to take the full advantage of the petascale computing capabilities being deployed by NSF, and will lead to dramatic increases in climate science productivity. The CAM-SE is being further extended as a nonhydrostatic dynamical core, with deep atmopshere options, which is an ongoing project.
High-Order Multiscale Atmospheric Model (HOMAM)
The High-Order Method Modeling Environment (HOMME), is a petascale hydrostatic framework, which employs the cubed-sphere grid system and high-order continuous or discontinuous Galerkin (DG) methods. Recently, the HOMME framework is being extended to a non-hydrostatic (NH) dynamical core, the “High-Order Multiscale Atmospheric Model” (HOMAM). Orography is handled by the terrain-following height-based coordinate system. To alleviate the stringent CFL stability requirement resulting from the vertical aspects of the dynamics, an operator-splitting time integration scheme based on the horizontally explicit and vertically implicit (HEVI) philosophy is adopted for HOMAM.
A discontinuos Galerkin nonhydrostatic model (Euler solver) in 3D Cartesian coordinates (HOMAM limited area model) has been developed. A GPU version of this model is under development. [Talk.pdf]
Nair R. D., L. Bao, and M. D. Toy, 2015: A Time-Split Discontinuous Galerkin Transport Scheme for Global Atmospheric Model. Procedia Computer Science, Vol. 51, p 2056–2065, doi:10.1016/j.procs.2015.05.471, [Paper.pdf] [Poster.pdf] [Talk.pdf]
Nair, R. D., L. Bao, M. D. Toy, and R. Kloefkorn, 2016: A High-Order Multiscale Global Atmospheric Model. 8th AIAA Atmospheric and Space Environments Conference, AIAA 2016-3888., DOI: 10.2514/6.2016-3888, [paper.pdf].