Conservative Finite-Difference Approximations of the Primitive Equations on Quasi-Uniform Spherical Grids

Abstract

A class of conservative finite-difference approximations of the primitive equations is given for quasi-uniform spherical grids derived from regular polyhedrons. The earth is split into several contiguous regions. Within each region, a coordinate system derived from central projections is used, instead of the spherical coordinate system, to avoid the use of inconsistent boundary conditions at the poles. The presence of artificial internal boundaries has no effect on the conservation properties of the approximations. Examples of conservative schemes, up to the second order in the case of a cube, are given. A selective damping operator is needed to remove the two-grid interval waves generated by the existence of internal boundaries.