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changes.mady.by.user Wuyin Lin

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changes.mady.by.user Charlie Zender

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title2. Source data grid description

Grid description info (e.g., SCRIP file) is needed for the source data in order to generate map files for remapping to target model grid. Charlie Zender generated the SCRIP file for the IFS data used here. 

/global/homes/z/zender/data/grids/f640_scrip.20190601.nc

In the case of not having a source grid description file, it can be inferred using NCO tool in the following format. (see also section 3.23 of nco NCO documentation). foo.nc is just a place holder.

~zender/bin_cori/ncks --rgr infer --rgr scrip=ncremap -d ifs_oper_T1279_scrip2016080100.nc -g ifs_oper_T1279_2016080100.nc foo.ncscrip.nc 


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title3. Generate map file

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,

export PATH=~wlin//local/opt/bin:~zender/bin_cori:$PATH . #to include the path to TempestRemap utilities and latest nco on cori

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

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title4. Horizontal remapping

Horizontal remapping using the subset of modified IFS file (see step 1) and TempestRemap generated mapfile

nice ~zender/bin_cori/ncks ncremap -5 --map=map_f640_to_ne512np4_highorder.20190618.nc \
ifs_oper_T1279_2016080100_mod_subset.nc ifs_oper_T1279_2016080100_mod_subset_to_e3sm_ne512np4.nc

This command is recorded in /project/projectdirs/m2136/analysis-IC/map_ifs_to_e3sm_horiz.ne512.sh. Similar commands can be found under that directory for other grid resolutions.

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