Version 5.0.7 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 5.0.7 has new fixes and features for ncremap and ncclimo
that ensure correct treatment of sub-gridscale fields and missing
values. ncremap now allows and adjusts for missing values in SGS
fields. Previously such missing values could botch SGS normalization.
Users of SGS regridding are encouraged to upgrade. Others might skip
this release.
New Features
-
ncremapnow emits a WARNING when a dataset contains a sub-gridscale (SGS) indicator variable, such aslandfrac(for ELM/CLM), ortimeMonthly_avg_iceAreaCell(for MPASSI), or aice (for CICE), and yet SGS regridding was not invoked. This will help avert some inadvertent misuse of the regridder by users unfamiliar with the need for SGS regridding of datasets where values are only valid over fractions of gridcells.ncremap -P elm --map=map.nc in.nc out.nc
http://nco.sf.net/nco.html#sgs -
ncremapnow allows for missing values in fields with valid SGS area.ncremappreviously assumed to be valid wherever sgs_frc > 0.0. This assumption is valid for ~95% of ELM/CLM fields. However, it low-biases landunit-specific fields (like TSOI, H2OSOI) in transition areas (e.g., ablation zone) with valid SGS, invalid landunit. Now sub-SGS values are extrapolated, incorrect though not crazy-bad. No more temperatures near 0.0 for landunit-specific fields in ELM/CLM. Deriving and using landunit area as SGS field is only correct method. The current method is the best possible with that uses a single SGS fraction for normalization.ncremap -P elm --map=map.nc in.nc out.nc
http://nco.sf.net/nco.html#sgs
Additional details are available in the ChangeLog.
