Selection of a staggered grid for inertia-gravity waves in shallow water

The problem of accuracy in propagating inertia-gravity waves on Arakawa grids is investigated. It is shown that the sole analysis of spatial discretization and the recommendation of the B-grid for coarse resolution models and C-grid for high resolution models must be re-analysed when time discretization is taken into account as well. For a chosen time discretization, a coarse C-grid is shown for example, to increase precision when using larger time-steps (up to the stability limit) whereas the precision of the B-grid decreases. Here, an analysis of error for different grids in function of the space-time resolutions and computational costs is presented and some recommendations on the choice of the particular staggered grid for a given application are outlined. Copyright (C) 2002 John Wiley Sons, Ltd.