Climate and Forecast Metadata Conventions

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The Climate and Forecast (CF)

data visualization
capabilities.

History and evolution

The CF conventions were introduced in 2003, after several years of development by a collaboration that included staff from U.S. and European climate and weather laboratories.

IOOS as a recommended standard (number 08-012) for the representation and transport of gridded data. The CF conventions are being considered by the NASA Standards Process Group (SPG) and others as more broadly applicable standards.[5]
[6]

Applications and user base

The CF conventions have been adopted by a wide variety of national and international programs and activities in the Earth sciences.

Coupled model intercomparison projects, which are widely used for the Intergovernmental Panel on Climate Change assessment reports.[8]
They are promoted as an important element of scientific community coordination by the
software components
, such as atmosphere and ocean components, as the model runs .[14]

Supported data types

CF is intended for use with

observational data
and have been adopted by a number of groups for such applications.

Supported data formats

CF originated as a standard for data written in netCDF, but its structure is general and it has been adapted for use with other data formats. For example, using the CF conventions with Hierarchical Data Format data has been explored.[16]

Design principles

Several principles guide the development of CF conventions:

  • Data should be self-describing, without external tables needed for interpretation.
  • Conventions should be developed only as needed, rather than anticipating possible needs.
  • Conventions should not be onerous to use for either data-writers or data-readers.
  • Metadata should be readable by humans as well as interpretable by programs.
  • Redundancy should be avoided to prevent inconsistencies when writing data.

Specific CF metadata descriptors use values of attributes to represent

  • Data provenance
    : title, institution, contact, source (e.g. model), history (audit trail of operations), references, comment
  • Description of associated activity: project, experiment
  • Description of data: units, standard_name, long_name, auxiliary_variables, missing_value, valid_range, flag_values, flag_meanings
  • Description of coordinates: coordinates, bounds, grid_mapping (with formula_terms); time specified with reference_time ("time since T0") and calendar attributes.
  • Meaning of grid cells: cell_methods, cell_measures, and climatological statistics.

A central element of the CF Conventions is the CF Standard Name Table. The CF Standard Name Table uniquely associates a standard name with each geophysical parameter in a data set, where each name provides a precise description of physical quantities being represented. Note that this is the string value of the standard_name attribute, not the name of the parameter. The CF standard name table identifies over 1,000 physical quantities, each with a precise description and associated canonical units. Guidelines for construction of CF standard names are documented on the conventions web site.

As an example of the information provided by CF standard names, the entry for sea-level atmospheric pressure includes:

  • standard name: air_pressure_at_sea_level
  • description: sea_level means mean
    Air pressure
    at sea level is the quantity often abbreviated as MSLP or PMSL.
  • canonical units: Pa

Software

  • NetCDF-Java Library parses CF Conventions and creates Coordinate System objects from them
  • OriginPro version 2021b supports[17] netCDF CF Convention. Averaging can be performed during import to allow handling of large datasets in a GUI software.
  • The xarray Python library parses and decodes data stored according to CF Conventions.
  • The Iris Python library "draws heavily from the NetCDF CF Metadata Conventions as a source for its data model".[18]

References

  1. ^ Gregory, Jonathan (2003). "The CF metadata standard" (PDF).
  2. ^ "Conventions for the Standardization of NetCDF files". May 1995. Archived from the original on 2010-05-27. Retrieved 2010-06-23.
  3. ^ "GDT netCDF conventions for climate data, version 1.3". March 14, 1999. Archived from the original on June 10, 2010. Retrieved June 23, 2010.
  4. ^ Lawrence, B.N. (2003). "Maintaining and Advancing the CF Standard for Earth System Science Community Data". Archived from the original on 2010-05-27.
  5. ^ Rew, Russ (2010). "CF Metadata Conventions" (PDF). Archived from the original (PDF) on 2014-04-04.
  6. ^ Domenico, Ben (2009). "Web Coverage Service (WCS) 1.1 extension for CF-netCDF 3.0 encoding" (PDF).
  7. ^ Projects and Groups Adopting or Encouraging the CF-Conventions as a Standard Archived August 23, 2010, at the Wayback Machine
  8. ^ "Report of the 12th Session of the JSC/CLIVAR Working Group on Coupled Modelling (WGCM)" (PDF). 2009.
  9. ^ Kinter, James L. III (2005). "Data Issues for WCRP Weather and Climate Modeling" (PDF).
  10. ^ Taylor, Karl (2005). "Issues Related to the Dissemination of Climate Model Output" (PDF).
  11. ^ Doutriaux, Charles (2010). "Climate Model Output Rewriter" (PDF).[permanent dead link]
  12. ^ Drach, Bob (2002). "Metadata Standards for Gridded Climate Data in the Earth System Grid". Archived from the original on 2004-09-12.
  13. ^ a b "NetCDF in ArcGIS 9.2". 2006. Archived from the original on 2010-06-14. Retrieved 2010-06-23.
  14. doi:10.1007/s12145-008-0016-1.{{cite journal}}: CS1 maint: multiple names: authors list (link
    )
  15. ^ V. Balaji (2008). "Metadata Standards for Gridded Climate Data in the Earth System Grid" (PDF). Archived from the original (PDF) on 2010-05-28.
  16. ^ Yang, M.; R. Duerr; C. Lee (2009). "Investigation of using HDF5 archival information packages (AIP) to store NASA ECS data". 25th Conference on International Interactive Information and Processing Systems (IIPS) for Meteorology, Oceanography, and Hydrology, 89th American Meteorological Society Meeting.
  17. ^ "NetCDF Importing and Processing". originlab.com. Retrieved 2021-05-11.
  18. ^ "Metadata - Iris Documentation". Retrieved 2023-02-10.

External links

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