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ncap2 -O --no_tmp_fl -s 'grid_corner_lon(50085604,:)={100.024421691894531,100.024421691894531,100.012207031250000,100.012207031250000};grid_corner_lat(50085604,:)={42.598628997802734,42.589633941650391,42.589637756347656,42.598632812500000};' hydro1k.nc hydro1k_ccw.nc

For complex reasons, as of 2020-07-10, the git code branch to be used for the mapping: the map HYDRO1K to ne1024np4 isrequires the Git code-branch hmb-hydro2-fix (located at https://github.com/nco/nco/tree/hmb-hydro2-fix). If the mapping target is a physics grid e.g ne512pg2 or ne1024pg2 then master is fineThe master NCO branch is fine for all other target grids, including ne512pg2 and ne1024pg2.

NCO commands to produce maps that convert HYDRO1K elevation data (on the fixed, pure-CCW grid) to any desired output grid should include appropriate options for niceness, format, and speed. First, the HYDRO1K grid is memory-intensive. Map-files based on it must be created on a node with plenty of RAM. For example, the HYDRO1K-to-ne1024np4 map requires about 120 GB RAM (if the SCRIP overlap mesh is NOT requested). Etiquette requires lowering the priority of memory and CPU-intensive jobs with the nice command on shared resources such as login-nodes. Second, the output weight and vertice arrays may exceed the capacities of the netCDF3 classic and 64-bit offset formats so we recommend setting the output format to CDF5 or to netCDF4-classic with the -5 or -7 switches, respectively. Third, the weight-generation code is threaded and our preliminary benchmarks show that it can scale well up to at least six threads. These options yield commands of the form

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SCRIPgrid_1km-merge-10min_HYDRO1K-merge-nomask_c130402.nc
SCRIPgrid_1km-merge-10min_HYDRO1K-merge-nomask_c130402_ccw.nc
map_hydro1k_to_ne1024np4_nco.20200210.nc
map_hydro1k_to_ne1024np4_nco.20200210_fix.nc

20200710: Update

To avoid regressions for the mapping HYDRO1K- > ne1024np4 the git code For complex reasons the map HYDRO1K to ne1024np4 requires the Git code-branch hmb-nydro2hydro2-fix (located at https://github.com/nco/nco/tree/hmb-hydro2-fix) should be used. If the mapping target is a physics grid e.g ne512pg2 or ne1024pg2 then master is fine. ). The master NCO branch is fine for all other target grids, including ne512pg2 and ne1024pg2.

20200423: Update:

While writing this documentation we discovered a regression in the NCO weight-generation that produces more (~100+) frac_b WARNINGS than we found in February. Henry Butowsky (Unlicensed) is working to understand and fix the cause of the regression, and will post another update here once more progress is made. Ben Hillman this documentation may be useful in constructing high-resolutions ELM IC’s.

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