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High resolution USGS topography file named USGS-topo-cube3000.nc (located in the CESM inputdata server here; note this is on a 3 km cubed sphere grid)
topography tool (
components/cameam/tools/topo_tool/cube_to_target)homme_tool ( same tool components/homme/test/tool, used to create SCRIP files described above).
Topography needs to be interpolated from a high resolution USGS file, and then doctored up a bit to allow the model to run stably with the new topography. The tool chain used to compute topography is documented in the following paper:
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Step (a) downsample USGS topography data to the atmosphere grid
Step (b) apply dycore-specific smoothing to reduce the amount of gravity wave noise if the topography is too rough. This is a tunable parameter, and a rigorous analysis probably needs to be performed to determine the optimal tuning parameter for future very-high-resolution atmosphere grids. For pg2 grids there is the extra step of generating consistent topo data on both the GLL (dynamics) and pg2 (physics) grid. (the tool may need additional work to support other pg values)
Step (c) based on the smoothed topography, compute the SGH and SGH30 surface roughness fields used by some parameterizations
Steps (a) and (c) use the topography tool located at components/eam/tools/topo_tool/cube_to_target in the E3SM repo. This requires the SCRIP dualgrid file which can be computed with homme_tool. cube_to_target is one of the last tools that needs a SCRIP dualgrid file. This tools should be upgraded to use an externally generated area averaging type map.
Step (b) requires running the homme_tool's smoothing algorithm. The namelist should be edited to specify the resolution (NE value) or grid file (RRM) grid and the amount of smoothing
Detailed instructions depend on which version of the model is being used:
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