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We not that the TempestRemap package (github link) understands both SE and FV grids and can produce map files dirctly from the CAM-SE Native grid. These mapping files are usually more accurate since they take advantage of the SE discretization. If ACME adopts TempestRemap mapping files, we will not need to use the SE dual grid shown above.
CAM-FV Grids
We also show some plots of grids used by the Lin-Rood CAM-FV model:
The first plot below shows the grid used by CAM-FV for all scalar fields. NCL refers to this as a "fixed" gridThe red dots show where the data are located, and the blue lines give the cells associated with each data point. Data is interpreted as cell averages at the red dots. Because of the lat/lon representation, data at the poles are actually duplicated for every longitude. A grid with equal spacing in both latitude and longitude will have dimensions (N+1) x 2N. Data at 180E = 180W are not duplicated in the file, and to convey this, we only plot red dots at 180W and not 180E.
The next plot shows what NCL refers to as the fixed offset grid (aka Uniform). Gaussian grids look nearly identical to these offset grids, except Gaussian grids use a spacing in latitude which is not quite equi-angular. A grid with the same equal spacing in both latitude and longitude will have dimensions N x 2N.