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NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
Current content can be found at unidata.ucar.edu.
To learn about what's going on, see About the Archive Site.
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 )'(
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