| Seminar: | CPS Seminar |
| date: | 2024 September 2 (Mon)13:00- |
| Room: | CPS Conference Room and Online (Hybrid meeting) |
| Speaker: | Yuta Kawai (Postdoctoral Researcher, RIKEN Center for Computational Science) |
| Title: | " Development of an atmospheric dynamical core based on the discontinuous Galerkin method considering future high-resolution atmospheric simulations " |
| Abstract: | With recent developments of large parallel supercomputers, a grid spacing in high-resolution global atmospheric simulations is approaching a spatial scale treated in the large-eddy simulation (LES). In dynamical cores of state-of-the-art global nonhydrostatic models, grid-point methods with the totally second-order accuracy are typically adopted. However, considering future global LESs, such lower-order schemes may be problematic because the discretization errors are possible to contaminate the effect of eddy viscosity terms with the turbulence model. Kawai & Tomita (2021) investigated the order of accuracy required for advection schemes in the LES of atmospheric boundary layer turbulence and indicated that the seventh- or eighth- order accuracy is required. To achieve such high-order accuracy in the framework of conventional grid-point methods, there are several problems; The data locality degrades due to the stencil enlargement and the formulation in the finite volume method becomes complex. To avoid the issues, we focus on the discontinuous Galerkin method (DGM), which is characterized by the high computational efficiency and simplicity for the high-order strategy. To investigate its applicability to the calculations of atmospheric flows, we constructed a regional LES model based on the DGM and attempted to understand the numerical properties (Kawai & Tomita, 2023). Further, we are now introducing a moist process and constructing a global model using a cubed-sphere projection. In this seminar, we will present our knowledge of the numerical accuracy required for the atmospheric LES. In addition, we will show the formulation of global LES model based on DGM and the results obtained from a validation experiment. |
| Keywords: | high-resolution atmospheric simulation, large-eddy simulation, discretization error, high-order fluid scheme, discontinuous Galerkin method |
| Organizer: | HAYASHI Yoshiyuki |