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NCO

The NCO toolkit manipulates and analyzes data stored in netCDF-accessible formats, including DAP, HDF4, and HDF5.

The netCDF Operators (NCO) comprise about a dozen standalone, command-line programs that take netCDF, HDF, and/or DAP files as input, then operate (e.g., derive new fields, compute statistics, print, hyperslab, manipulate metadata, regrid) and output the results to screen or files in text, binary, or netCDF formats. NCO aids analysis of gridded and unstructured scientific data. The shell-command style of NCO allows users to manipulate and analyze files interactively, or with expressive scripts that avoid some overhead of higher-level programming environments.

Many E3SM Diagnostic tools rely on NCO, the MPAS-Analysis and E3SM Processflow packages directly use NCO for E3SM climatology generation, regridding, and time-series variable extraction. These NCO output files are then used as input for the AMWG, E3SM Diagnostics, and E-prime Diagnostic packages. Additionally, the AMWG, E3SM Diagnostics, and E-Prime packages compare E3SM simulations against observational climatologies that were largely formatted, annotated, climatologized, and regridded with NCO. E3SM simulations input to iLAMB are also typically regridded with NCO. Hence NCO is a core component of and is automatically loaded within the E3SM-Unified Conda environment, and can also be individually installed as described below.

NCO Documentation

The netCDF Operators (NCO) are freely available in source form and as pre-built binaries (much easier) on all operating systems, and the binaries are pre-installed on all major E3SM machines.
The primary documentation source is the NCO homepage, which contains instructions to download, build, and install, and pointers to the manual, FAQ, and examples. The recapitulation below includes some information specifically developed for E3SM users, and is not available on the homepage.

Requested Acknowledgement:

Zender, C. S. (2008), Analysis of Self-describing Gridded Geoscience Data with netCDF Operators (NCO), Environ. Modell. Softw., 23(10), 1338-1342, doi:10.1016/j.envsoft.2008.03.004.
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