...

In order to adapt this to the physgrid we need to use an additional command to subdivided these elements into the number of FV cells we want. Similar to the example given above is that when mapping between grids we would need to indicate to TempestRemap that these "elements" are actually finite volume cells with a special flag (see mapping section below).

So if we want an ne30pg3 ne30pg2 file, and we initially created an ne30 exodus files with this command:

...

${tempest_root}/bin/GenerateVolumetricMesh --in ${output_root}/ne30.g --out ${output_root}/ne30pg3ne30pg2.g --np 3 2 --uniform

Generating a Scrip File

For mapping GLL grids without TempestRemap (or plotting GLL grid data) we need to "re-interpret" the representation of data on the GLL grid into a finite volume grid. Step #2 in the step-by-step guide discusses how to do this with the "dual grid" approach. It's worth noting that this is not a visually accurate representation of the data, but the area of the FV cells produced by the dual grid are consistent with the GLL weights so that spatial sums and averages can be computed in an intuitive way. Another caveat of the dual grid method is that the generation of the scrip grid description file requires an iterative process that can can take a very long time for large grids.

An advantage of the physgrid is that we don't have to worry about this nonsense because the data is naturally represented by finite volumes. There's a simple TempestRemap command that can quickly convert from exodus to scrip file types using the following command:

${tempest_root}/bin/ConvertExodusToSCRIP --in ne30pg3.g --out ne30pg3_scrip.nc

The resulting scrip file can be used for mapping with ESMF or plotting physgrid data on the native grid. 

Mapping Files

The "ncremap -P mwf" procedure encapsulates several commands to generate all the required map files for a run without the physgrid, but since these commands are specific to using the spectral element grid, we need different commands when using the physgrid. We can implement a comparable procedure in ncremap if we want by submitting a PR to the NCO repository.

The example below shows the commands needed to generate all mapping files for a tri-grid configuration with the atmosphere on the ne30pg2 grid.. 

...

Mapping Files

The "ncremap -P mwf" procedure encapsulates several commands to generate all the required map files for a run without the physgrid, but since these commands are specific to using the spectral element grid, we need different commands when using the physgrid. We can implement a comparable procedure in ncremap if we want by submitting a PR to the NCO repository.

The example below shows the commands needed to generate all mapping files for a tri-grid configuration with the atmosphere on the ne30pg2 grid.. 

atm_grid_file=ne30pg2.g
ocn_grid_file=ocean.oEC60to30v3.scrip.181106.nc
lnd_grid_file=SCRIPgrid_0.5x0.5_nomask_c110308.nc
atm_name=ne30pg2
ocn_name=oEC60to30v3
lnd_name=r05
alg_name=mono
map_opts='--in_type fv --in_np 1 --out_type fv --out_np 1 --out_format Classic'
date=200110
ncremap -a tempest --src_grd=$ocn_grid_file --dst_grd=$atm_grid_file -m map_${ocn_name}_to_${atm_name}_${alg_name}.${date}.nc -W $opts
ncremap -a tempest --src_grd=$atm_grid_file --dst_grd=$ocn_grid_file -m map_${atm_name}_to_${ocn_name}_${alg_name}.${date}.nc -W $opts --a2o
ncremap -a tempest --src_grd=$ocn$lnd_grid_file --dst_grd=$atm_grid_file -m mapm map_${ocnlnd_name}_to_${atm_name}_${alg_name}.${date}.nc nc -W $opts 
ncremap -a tempest --src_grd=$atm_grid_file --dst_grd=$ocn$lnd_grid_file -m mapm map_${atm_name}_to_${ocnlnd_name}_${alg_name}.${date}.nc -W $opts 
ncremap --a2o
ncremap -a tempest --src_grd=$lnd_grid_file --dst_grd=$atm$ocn_grid_file -m map_${lnd_name}_to_${atmocn_name}_${alg_name}.${date}.nc -W $opts --a2o
ncremap -a tempest --src_grd=$atm$ocn_grid_file --dst_grd=$lnd_grid_file -m map_${atmocn_name}_to_${lnd_name}_${alg_name}.${date}.nc -W $opts ncremap -a tempest --src_grd=$lnd_grid_file --dst_grd=$ocn_grid_file -m map_${lnd_name}_to_${ocn_name}_${alg_name}.${date}.nc -W $opts --a2o
ncremap -a tempest --src_grd=$ocn_grid_file --dst_grd=$lnd_grid_file -m map_${ocn_name}_to_${lnd_name}_${alg_name}.${date}.nc -W $opts 

...

Domain Files

No change in the procedure for generating domain files except that the physgrid grid and mapping files described above need to be used because the physics grid is used when communicating with the coupler, which is primarily where the domain files are neededThe path to these files needs to added to the appropriate section of cime/config/e3sm/config_grids.xml.

Domain Files

No change in the procedure for generating domain files except that the physgrid grid and mapping files described above need to be used because the physics grid is used when communicating with the coupler, which is primarily where the domain files are needed. 

Generating a Scrip File

For mapping GLL grids without TempestRemap (or plotting GLL grid data) we need to "re-interpret" the representation of data on the GLL grid into a finite volume grid. Step #2 in the step-by-step guide discusses how to do this with the "dual grid" approach. It's worth noting that this is not a visually accurate representation of the data, but the area of the FV cells produced by the dual grid are consistent with the GLL weights so that spatial sums and averages can be computed in an intuitive way. Another caveat of the dual grid method is that the generation of the scrip grid description file requires an iterative process that can can take a very long time for large grids.

An advantage of the physgrid is that we don't have to worry about this nonsense because the data is naturally represented by finite volumes. There's a simple TempestRemap command that can quickly convert from exodus to scrip file types using the following command:

${tempest_root}/bin/ConvertExodusToSCRIP --in ne30pg2.g --out ne30pg2_scrip.nc

The resulting scrip file can be used for mapping with ESMF or plotting physgrid data on the native grid. 

Topography

The dycore requires smoothed topography on the GLL grid, and the physics parameterization for turbulent mountain stress operates on the physics (FV) grid. PRs #3267 and #3406 introduced a new file format for topography and related tools that provide consistent topography data on each grid. There are two new tools to support this new treatment of topography.

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