Page Comparison

Normally, horizontal map files can be generated using either ESMF_RegridWeightGen or TempestRemap via wrapper ncremap. However, during the process of generating the IC file for ne1024, it is found that the resulting data using the mapfile generated by ESMF_regrid contain invalid data outside of normal range of values. The cause has not been identified. Though ESMF_regrid generated mapfile appears to work ok for ne512, TempestRemap is chosen to suit the general need of SCREAM project for global simulations at km scale resolution.

The mapfile from IFS f640 to ne512 can be generated using TempestRemap in the following format. Use e3sm_unified to set up proper path (cori as an example),

including path to TempestRemap executables and ncremap

source /global/project/projectdirs/acme/software/anaconda_envs/load_latest_e3sm_unified.sh

nice ncremap -a fv2se_stt --src_grd=/global/homes/w/wlin/ACME/remap/IFS_T1279/f640_scrip.20190601_CCW_nc6.nc \
     --dst_grd=/project/projectdirs/acme/bhillma/grids/ne512np4/descriptor_files/ne512.g \
     -m /global/homes/w/wlin/gscrc/DYAMOND/map_f640_to_ne512np4_highorder.20190618.nc

Do apply nice when running on login nodes because it can take very high amount of memory (70+ GB for ne1024)

The example command is recorded in  /project/projectdirs/m2136/analysis-IC/gen.mapfiles.TR.ne512.hiorder

This step is in preparation for vertical interpolation using the new NCO functionality. NCO vertical interpolation uses a vertfile to define destination vertical grid layout.  For EAM's hybrid vertical coordinate, it takes PS as well as hybrid coordinate coefficients – If PS is not provided in the vertfile,  it would assume the same PS as in the source data. In this workflow, the vertfile included the adjusted PS that account for the mismatch in topography between source data and model. The topography in source data has been remapped to destination grid after step 4. Without adjusting for the mismatch, the resulting interpolated initial file could excite fast gravity wave via dynamical adjustment during first few steps of simulation, hence requiring much shorter time stepping than intended for the target resolution – a process commonly called spin-up.

This step is handled by /project/projectdirs/m2136/analysis-IC/vertfile_topoadj_ne512.sh

It requires a generic EAM vertical coordinate file, the topo file for target grid, and PS, PHIS and bottom level temperature extracted from horizontally remapped file after step 4. The generic vertical coordinate file must have same number of levels as for the target configuration (i.e., the required IC file). See the comments in the script for more info.