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Version 4.9.8 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 4.9.8 contains a few cool features. These include support for unpacking sparse 1D (S1D) data and restart files used for plant functional types and multiple elevation classes, splitting monthly resolution timeseries that do not begin/end in Jan/Dec, seamless climos for the E3SM ice-sheet model (MALI), and corner-case bugfixes for inferring grid files and handling sub-gridscale data.

New Features

1. Windows builds should now contain the nces.exe and ncrcat.exe executables. Previously, Windows users had to run nces and ncrcat commands indirectly, using ncra.exe -Y nces ..., or manually copy ncra.exe to nces.exe, etc. The executables are identical, and behave differently depending on their invocation name.

   ncrcat             ... # These all do the same thing
   ncrcat.exe         ... # "
   ncra.exe -Y ncrcat ... # "
   

   http://nco.sf.net/nco.html#ncrcat
   http://nco.sf.net/nco.html#nces
2. ncclimo supports new options --mth_srt and --mth_end in splitter mode. The arguments to these options specify the (1-based) month in which the requested timeseries will begin and end, respectively, and these default to 1 (January) and 12 (December). To extract 14-month timeseries from individual monthly input files one would use, e.g.,

   ncclimo --yr_srt=1 --yr_end=2 --mth_srt=4 --mth_end=5 ...

   http://nco.sf.net/nco.html#ncclimo
   http://nco.sf.net/nco.html#mth_srt
   http://nco.sf.net/nco.html#mth_end
3. ncclimo/ncremap support analysis of MALI land ice model output when invoked with the new '-P mali' or '--prc_typ=mali' options.

   ncclimo -P mali -s 1 -e 2 -o climo mali.hist*.nc
   ncremap -P mali --map=map.nc in.nc out.nc
   

   http://nco.sf.net/nco.html#prc_typ
   http://nco.sf.net/nco.html#ncclimo
4. ncks now supports unpacking sparse 1D (S1D) ELM/CLM data and restart files for plant functional types (PFTs) and multiple elevation classes (MECs).

   ncks --s1d -v cols1d_topoglc --hrz=elm_mali_ig_history.nc \
       elm_mali_restart.nc out.nc
   ncks --s1d -v GPP,pfts1d_wtgcell elm_crop_history.nc out.nc
   

   After such S1D datasets have been "unpacked", they may easily be regridded with, e.g., ncremap. This feature is under continued development and user-feedback would be appreciated. Documentation does not yet exist.
   http://nco.sf.net/nco.html#ncks
5. ncks now prints more informative messages when users attempt to vertically interpolate variables (such as EAM/CAM US, VS) in hybrid coordinate data files that contain multiple grids (e.g., the normal and staggered grids) though only one surface pressure variable.
   http://nco.sf.net/nco.html#ncremap
6. As of version 4.9.8 the default ncremap behavior is to omit the staggered grid from output files on an cap grid. The new flag --stg_grd turns-on outputting the staggered grid, and thus recovers the previous default behavior.

Additional details are available in the ChangeLog.