On Structure-Preserving Ocean Modelling

Modelling of global ocean dynamics is based on the Ocean Primitive Equation. These equations describe the ocean as an incompressible two-component fluid under the Boussinesq and the hydrostatic approximation. We describe a structure-preserving discretization of the Ocean Primitive Equations. This discretizations forms the foundation of the ocean general circulation model ICON-O. ICON-O is the ocean component of Max-Planck Institute for Meteorology's newly developed Earth System Model ICON-ESM and the ocean model of the ICON modelling system. The novel numerical approach of ICON-O rests on a discrete weak form that allows to control spurious modes in a way that is compatible with discrete conservations laws. We present a numerical analysis of the discrete algorithm and an experimental evaluation. Global ocean simulation are carried out and compared to observations in order to to demonstrate the physical soundness of the model.