A multi-moment transport model on cubed-sphere grid

A conservative, single-cell-based semi-Lagrangian transport model is proposed in this paper. Using multi-moment concept, an additional moment, i.e. volume-integrated average (VIA), is treated as the model variable besides the point value (PV) updated in the traditional semi-Lagrangian schemes. A quadratic interpolation function is constructed based on local degrees of freedom defined within each single cell. The PV moment is advanced by the semi-Lagrangian formulation, whereas the VIA moment is updated by a finite volume formulation to rigorously ensure the numerical conservation. The numerical fluxes are computed from the PV moments defined along the boundary edges of the control volume. The scheme is extended to the spherical geometry through the application of the cubed-sphere grid that eliminates the polar singularity in the conventional longitude/latitude coordinates by using the quasi-uniform grid spacing covering the whole sphere. The single-cell-based scheme is well suited for the treatment of the connections between different patches. A simple quasi-monotone limiter to the PV moment is applied to suppress non-physical oscillations. The proposed scheme has been validated via representative benchmark tests and the performance is competitive to other existing transport schemes