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Version 4.7.2 of the netCDF Operators (NCO) has been released. NCO is an Open Source package that consists of a dozen standalone, command-line programs that take netCDF files as input, then operate (e.g., derive new data, average, print, hyperslab, manipulate metadata) and output the results to screen or files in text, binary, or netCDF formats.

The NCO project is coordinated by Professor Charlie Zender of the Department of Earth System Science, University of California, Irvine. More information about the project, along with binary and source downloads, are available on the SourceForge project page.

From the release message:

Version 4.7.2 contains one new cool feature for ncremap, one important bugfix for the splitter, and assorted minor improvements and fixes. ncremap now implements E3SM-recommended Tempest remapping algorithms for all combinations of FV↔SE remapping for flux and state variables. The ncclimo splitter functionality has an important bugfix for cases when the total number requested time-periods (usually years) of averaging is not evenly divisible by the maximum number of time-periods per output-file.

New Features

1. ncremap implements E3SM-recommended Tempest remapping algorithms. ncremap can now easily generate and use the each of the six E3SM-recommended mappings between FV↔SE flux and state variables. ncremap automatically employs the "boutique" TempestRemap options so long as Tempest2 is installed.

   ncremap -a se2fv_flx --src_grd=ne30.g --dst_grd=fv.nc -m map.nc
   ncremap -m map.nc in.nc out.nc
   Canonical algorithm names are se2fv_flx, se2fv_stt, se2fv_alt,
   fv2se_flx, fv2se_stt, fv2se_alt.

   http://nco.sf.net/nco.html#ncremap
2. ncremap supports "canonical" NCO argument ordering.
   Canonical ordering is: command [options] [input] [output]
   Previously ncremap required the use of options (like -i and -o) or pipes to supply filenames:

   ncremap -m map.nc -i in.nc -o out.nc
   ncremap -m map.nc -o out.nc in.nc
   ncremap -m map.nc -O out_dir in1.nc in2.nc
   ls in.nc | ncremap -m map.nc -o out.nc
   ncremap -m map.nc -o out.nc < in.nc

   Now ncremap finally supports the canonical ordering of command line arguments most frequently desired for one-off regridding, where a single input and output filename are supplied as command-line positional arguments without switches, pipes, or redirection:

   ncremap -m map.nc in.nc out.nc

   http://nco.sf.net/nco.html#ncremap
   http://nco.sf.net/nco.html#alg_typ
3. ncremap supports a --mss_val=val option for MPAS data. ncremap pre-processes MPAS datasets (indicated with -P mpas) and annotates their floating point variables with the _FillValue attribute. By default it sets _FillValue to the correct value for MPAS ocean and sea-ice models. However, the MPAS land-ice model uses a different missing value. Hence this option is usually invoked as --mss_val=-1.0e36 to facilitate processing of MPAS land-ice datasets.

   ncremap -P mpas --mss_val=-1.0e36 -s ais.nc -i data.nc -g fv.nc -o out.nc

   http://nco.sf.net/nco.html#ncremap
   http://nco.sf.net/nco.html#mss_val_ncremap
4. ncclimo has improved support for NCAR cheyenne batch queues. Previously ncclimo -p mpi failed on Cheyenne due to differences between SGI MPT mpirun and "normal" mpirun syntax. Now ncclimo uses mpirun syntax expected by SGI MPT on cheyenne.

   qsub -A SCSG0002 -l select=12:ncpus=36:mpiprocs=1 -l
   walltime=00:30:00 -q regular -N ncclimo -j oe -m e -o ~/ncclimo.out

   http://nco.sf.net/nco.html#ncclimo

Additional details are available in the ChangeLog.