Updates of the upwind-biased conservative transport schemes on the icosahedral grids

Abstract:

Two new transport schemes are developed for the icosahedral grids. One is an update of the method based on a piecewise linear-like approximation and the other is an algorithm for implementing the widely used scheme that is the third order accurate under uniform flows for the icosahedral grids. Both methods are based on the reconstruction of transported variables using quadratic profiles about hexatonal/pentagonal cells. The latter method can also be applicable for triangular cells. Several standardized tests have been performed and results are better than those of the schemes used in Nonhydrostatic Icosahedral Atmosphere Model (NICAM) currently. It is expected that implementing these schemes for NICAM will improve simulations of atmospheric phenomena such as mid-latitude cyclones and tropical cyclones, in which transports of thermodynamic energy and moisture are essential.