netCDF Operators NCO version 5.1.2 accede to the Silicon Throne
http://nco.sf.net (Homepage, Mailing lists, Help)
http://github.com/nco/nco (Source Code, Issues, Releases)
What's new?
Version 5.1.2 improves support for horizontal regridding, vertical
interpolation, or both, on ultra high-resolution model output.
Users of such functionality may benefit from upgrading, otherwise
this release can be skipped.
Work on NCO 5.1.3 has commenced and aims to add support for Zarr S3
stores and to polish support for new codecs.
Enjoy,
Charlie
NEW FEATURES (full details always in ChangeLog):
A. ncremap supports new options --vrt_in=vrt.nc and --ps_nm=ps_nm.
The argument to --vrt_in is a vertical coordinate file that contains
the pure or hybrid pressure information for the input data to be
vertically interpolated. Previously, this information was required
to be present in the input data file. However, SCREAM/EAMxx and
other ultra-high resolution models may choose to output the grid
information in separate files from the geophysical fields. This
can save considerable space, especially for hybrid sigma-pressure
coordinates with time-varying surface pressure. To complement the
--vrt_in option, there is now a --vrt_out option to explicitly
identify the file containing the output vertical grid. The best
practice is now to use --vrt_out (instead of --vrt or --vrt_fl,
which still work) to specify the output vertical grid and clearly
distinguish it from the input vertical grid, if any.
ncremap --vrt_out=vrt2.nc # Output vertical grid option new name
ncremap --vrt_in=vrt1.nc --vrt_out=vrt2.nc ... # Specify both grids
Thanks to Paul Ullrich (UCD) for suggesting these options.
http://nco.sf.net/nco.html#ncremap
http://nco.sf.net/nco.html#vrt_in
http://nco.sf.net/nco.html#vrt_out
B. Previously the vertical interpolation feature required that the
surface pressure field for hybrid coordinates be named PS.
Now the name of the surface pressure field can be changed using the
convenient ps_nm option. Moreover, if the argument of --ps_nm
includes a filepath separator (slash or backslash), then the
portion preceding the final separator will be treated as a filename
path, and the final portion will be treated as the surface pressure
variable name:
ncremap --ps_nm=ps ... # Surface pressure is ps not PS
ncremap --ps_nm=/path/to/vrt.nc/ps ... # Use ps from vrt.nc
http://nco.sf.net/nco.html#ncremap
http://nco.sf.net/nco.html#ps_nm
C. ncclimo and ncremap support a new procedure type option, -P eamxx.
This option automatically generates ncremap flags useful for E3SM
EAMxx datasets. In addition to their typically ginormous size, these
datasets have different dimension and variable names than EAM/CAM.
Current -P eamxx causes ncremap to do two actions automatically:
(1) Permute the horizontal dimensions to be most rapidly varying by
generating the option --pdq_opt=ilev,lev,dim2,col prior to horizontal
regridding. (2) Search for surface pressure under the name ps instead
of PS prior to vertical interpolation of hybrid-pressure grids.
ncremap --pdq_opt=ilev,lev,dim2,col # Manual dimension permutation
ncremap --ps_nm=ps # Manual surface pressure renaming from PS to ps
ncremap -P eamxx # Both options automagically
Thanks to Paul Ullrich (UCD) for suggesting these options.
http://nco.sf.net/nco.html#ncremap
http://nco.sf.net/nco.html#prc_typ
D. ncremap has changed the default behavoir of outputting the
staggered grid to finite volume (FV) destination grids from opt-out
to opt-in. This means that it is no longer necessary to specify
--no_stg_grd when regridding. Instead, it is necessary to specify
--stg_grd when the staggered grid (including variables slat and slon)
is desired as additional information in the regridded file.
ncremap --no_stg_grd ... # Old method of opting out
ncremap ... # New default behavior
ncremap --stg_grd ... # Recovers old default behavior
http://nco.sf.net/nco.html#stg_grd
E. ncremap vertical interpolation routines now recognize variables
with names T_mid and VerticalLayerMidpoint as containing temperature
and geopotential height, respectively. These variable names are used
in SCREAM/EAMxx. The default extrapolation for these variables now
behaves the same as T and Z3 for EAM/CAM datasets.
http://nco.sf.net/nco.html#vrt_ntp
http://nco.sf.net/nco.html#vrt_xtr
F. ncz2psx now has a man page.
Full documentation for ncz2psx is expected to become available
once NCO fully supports the Amazon S3 scheme for NCZarr in 2023.
http://nco.sf.net/nco.html#ncz2psx
BUG FIXES:
A. Some operators in NCO 5.1.1 would segfault instead of printing
usage information when called without any arguments. 5.1.2 fixes this.
B. Previous versions of ncks accidentally printed the ncgen command
to generate binary from CDL files assuming the input file was
NC_FORMAT_64BIT_OFFSET instead of its actual type. 5.1.2 fixes this.
Full release statement at http://nco.sf.net/ANNOUNCE
--
Charlie Zender, Earth System Sci. & Computer Sci.
University of California, Irvine 949-891-2429 )'(
