  The computational fluid dynamics on a sphere is relevant to global
simulations of geophysical fluid dynamics. Using the conventional
spherical-polar (or lat-lon) grid results in a singularity at the poles, with
orders of magnitude smaller cell sizes at the poles in comparison to the
equator. To address this problem, we developed a general circulation model
(dynamic core) with a gnomonic equiangular cubed-sphere configuration. This
model is developed based on the Simulating Nonhydrostatic Atmospheres on
Planets (SNAP) model, using a finite volume numerical scheme with a
Riemann-solver-based dynamic core and the vertical implicit correction (VIC)
scheme. This change of the horizontal configuration gives a 20-time
acceleration of global simulations compared to the lat-lon grid with a similar
number of cells at medium resolution. We presented standard tests ranging from
2D shallow-water models to 3D general circulation tests, including earth-like
planets and shallow hot Jupiters, to validate the accuracy of the model. The
method described in this article is generic to transform any existing
finite-volume hydrodynamic model in the Cartesian geometry to the spherical
geometry.
