A New Ocean Model On The Uniform-Jacobian Cubic Grid

The Uniform-Jacobian Ocean Model is formulated on the non-orthogonal Uniform-Jacobian cubic grid of Purser and Rančić (2011), which offers a smooth transition of coordinate lines across the panel edges of the projected cube. UCOM is a z-coordinate model that uses a split-explicit flux-conserving approach to solve the hydrostatic primitive equations. It uses an R-grid (reversible staggering for the velocity components) for good gravity wave dispersion behaviour (McGregor, 2005). UCOM is applied to perform eddy-resolving simulations with a focus on the Southern Ocean at very high (~10 km) horizontal resolution, with the purpose of informing the statistical parameterisation of the Southern Ocean mixed layer in low-resolution Earth System Models. This research stems from the critical importance of the Southern Ocean mixed layer in determining the ocean-atmosphere carbon flux. Here were present the dynamic core and numerical solution procedures of UCOM, before demonstrating its scalability and numerical efficiency through the test case of the linear advection of a cosine bell and global mesoscale eddy-resolving simulations. All simulations have been performed on the computer clusters of the Centre for High Performance Computing (CHPC) in South Africa.

References

McGregor J.L. (2005). Geostrophic Adjustment for Reversibly Staggered Grids. Monthly Weather Review 133 1119-1128

Purser R. and Rančić M. (2011). A standardized procedure for the derivation of smooth and partially overset grids on the sphere, associated with polyhedra that admit regular griddings of their surfaces. Part I: Mathematical principles of classification and construction. NOAA/NCEP Office Note 57 pp.