Development of the Nonhydrostatic Unified Model of the Atmosphere (NUMA): Limited-Area Mode (Preprint)
Abstract
This paper describes a Nonhydrostatic Unified Model of the Atmosphere (NUMA) based on a spectral element, or high-order continuous Galerkin (CG) spatial discretization utilizing 3D hexahedral elements. The nonhydrostatic dynamical core, based on the compressible Euler equations, is appropriate for both limited-area and global atmospheric simulations. In this paper we restrict our attention to 3D limited-area phenomena; global atmospheric simulations will be presented in a follow-up paper. A suite of explicit and semi-implicit time-integrators is presented. Domain decomposition and communication algorithms utilized by our distributed memory implementation is presented, allowing efficient evaluation of the the direct stiffness summation (DSS) operator. Numerical verification of the model is performed using four test cases: 1) 2D inertia-gravity waves, 2) flow past a 3D linear hydrostatic mountain, 3) flow past a 3D nonlinear mountain and 4) 3D buoyant convection of a bubble in a neutral atmosphere; these tests indicate that NUMA can simulate the necessary physics of a dry numerical weather prediction dynamical core. Scalability for the explicit dynamical core is demonstrated for 12288 cores on TACC?s Ranger cluster, while the semi-implicit core is shown to scale to 4096 cores on the same architecture.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 14, 2011
- Accession Number
- ADA546276
Entities
People
- Francis Giraldo
- James F. Kelly
Organizations
- Naval Postgraduate School