| Full text | |
| Author(s): |
Lapolli, Fabricio Rodrigues
;
Peixoto, Pedro da Silva
;
Korn, Peter
Total Authors: 3
|
| Document type: | Journal article |
| Source: | Ocean Modelling; v. 189, p. 18-pg., 2024-03-06. |
| Abstract | |
One important tool at our disposal to evaluate the robustness of Global Circulation Models (GCMs) is to understand the horizontal discretization of the dynamical core under a shallow water approximation. Here, we evaluate the accuracy and stability of different methods used in, or adequate for, unstructured ocean models considering shallow water models. Our results show that the schemes have different accuracy capabilities, with the A- (NICAM) and B -grid (FeSOM 2.0) schemes providing at least 1st order accuracy in most operators and time integrated variables, while the two C -grid (ICON and MPAS) schemes display more difficulty in adequately approximating the horizontal dynamics. Moreover, the theory of the inertia -gravity wave representation on regular grids can be extended for our unstructured based schemes, where from least to most accurate we have: A-, B, and C -grid, respectively. Considering only C -grid schemes, the MPAS scheme has shown a more accurate representation of inertia -gravity waves than ICON. In terms of stability, we see that both A- and C -grid MPAS scheme display the best stability properties, but the A -grid scheme relies on artificial diffusion, while the C -grid scheme does not. Alongside, the B -grid and C -grid ICON schemes are within the least stable. Finally, in an effort to understand the effects of potential instabilities in ICON, we note that the full 3D model without a filtering term does not destabilize as it is integrated in time. However, spurious oscillations are responsible for decreasing the kinetic energy of the oceanic currents. Furthermore, an additional decrease of the currents' turbulent kinetic energy is also observed, creating a spurious mixing, which also plays a role in the strength decrease of these oceanic currents. (AU) | |
| FAPESP's process: | 21/06176-0 - Numerical methods for a new generation of weather and climate models |
| Grantee: | Pedro da Silva Peixoto |
| Support Opportunities: | Research Grants - Research Program on Global Climate Change - Young Investigators - Phase 2 |