Difference between revisions of "CF Naming Conventions"

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{{WCS Glossary
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== AQ CF standard names==
|Glossary Domain=WCS, HTAP
 
|TermDesc=CF Metadata Conventions support interoperability of Earth Science data. A central element of the CF Conventions is the [http://cf-pcmdi.llnl.gov/documents/cf-standard-names Standard Name Table], which uniquely associates each standard name with a geophysical parameter, named according to the [http://cf-pcmdi.llnl.gov/documents/cf-standard-names CF Naming Guidelines].  These  can be used to '''find''' or compare datasets in catalog browsers such as [[AQ_uFIND]].  As of 2010, there are 680 CF-registered [http://cf-pcmdi.llnl.gov/documents/cf-standard-names Atmospheric Chemistry names], covering mostly model-generated parameters. The naming of observation-parameters is poorly covered.
 
|Links=[[CF Conventions]], [http://cf-pcmdi.llnl.gov/documents/cf-standard-names/standardized-region-names Standardized Geographic Region Names]
 
* [[CF Conventions]]
 
|Contributors=Christiane Textor with [[CFpeople]].
 
|History=The naming activity was initiated in 2006 and coordinated by [[User:ChristianeTextor|ChristianeTextor]]. An ''ad hoc'' [[CFpeople|vitual workgroup]] constructed and [[Talk:Air_Quality/Chemistry_Naming_Conventions| discussed]]    the new CF standard_names for air chemistry and aerosols using a [[Air_Quality/Chemistry_Naming_Conventions| wiki workspace]]. The names were submitted to the [http://www.cgd.ucar.edu/mailman/listinfo/cf-CF CF Community] for approval and added the CF Names table in 2007. The extension of standards names list to include observational and other atmospheric chemistry parameters awaits new community initiatives.
 
}}
 
=== List of Chemical Species and Aerosols ===
 
The [[List_of_chemical_species_and_aerosols| list of chemical species and aerosols]], (as of October 29 2008) contains over 100 entries, in alphabetical order. The question mark indicates a [[Modfication of existing CF standard names | modification of existing CF standard names]] is suggested for these species. There is a strong need to further discuss and refine the chemical/aerosol naming conventions.
 
  
=== CF Naming Procedure ===
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This is the work space associated with the [http://wiki.esipfed.org/index.php/Standards_and_Conventions_for_WCS_Server#CF_Conventions CF conventions description]. While the actual approval process for new standard names happens exclusively via the CF mailing list, you can use these pages to prepare such discussions, monitor progress or ventilate new ideas. For additional information what this is about, please consult the [http://wiki.esipfed.org/index.php/Standards_and_Conventions_for_WCS_Server#CF_Conventions main page on ESIP], the [http://cf-pcmdi.llnl.gov/ CF home page] or directly the [http://cf-pcmdi.llnl.gov/documents/cf-conventions/latest-cf-conventions-document-1 latest CF standard document] or [http://cf-pcmdi.llnl.gov/documents/cf-standard-names/ standard name table].
New standard_names are defined through a step-wise procedure, see [http://cf-pcmdi.llnl.gov/ the CF conventions web site]. Many new proposals for standard names for aerosols and chemicals are under discussion at the [http://www.cgd.ucar.edu/mailman/listinfo/cf-CF CF mailing list]. This requires the development of a general approach on how to proceed. See [[CF Standard Names - Construction of Atmospheric Chemistry and Aerosol Terms|Construction of Atmospheric Chemistry and Aerosol Terms]] for further discussion.
 
  
=== CF Naming Example ===
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=== Discussion of standard name attributes for AirNow and RSIG variables ===
An example CF standard name for Atmospheric Chemistry extracted from the [http://cf-pcmdi.llnl.gov/documents/cf-standard-names/standard-name-table/15/cf-standard-name-table.html CF Standard Name Table]
 
  
''standard_name:'' mass_concentration_of_ammonium_dry_aerosol_in_air <br>
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* AirNow variable list with available and suggested standard_name attributes as well as suggested points for discussion [[Media:AirNow_Main_Params_mgs.doc]]
''long_name:'' Mass concentration means mass per unit volume and is used in the construction mass_concentration_of_X_in_Y, where X is a material constituent of Y. A chemical species denoted by X may be described by a single term such as 'nitrogen' or a phrase such as 'nox_expressed_as_nitrogen'. "Aerosol" means the suspended liquid or solid particles in air (except cloud droplets). Aerosol takes up ambient water (a process known as hygroscopic growth) depending on the relative humidity and the composition of the aerosol. "Dry aerosol" means aerosol without water. The chemical formula for ammonium is NH4.<br>
 
''unit:'' kg m-3
 
  
== Applications of CF Atmospheric Chemistry Names ===
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* Commented RSIG variable list (only partially commented due to sheer size) [[Media:rsig_variables.xls]]
The CF convention for naming atmospheric chemicals and aerosols has been adopted by the following model intercomparisons (state of July 2008):
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* [http://www.htap.org/ Task Force on Hemispheric Transport of Air Pollution (TF HTAP)]
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Brief summary: many quantities contained in either variable set have already been defined in the [http://cf-pcmdi.llnl.gov/documents/cf-standard-names/ CF standard name table] or they have close counterparts which require only simple additions to this table (for example adding another species name to the available list of "mole_fraction_of_X_in_air"). Some more discussion is needed on the following points:
* [http://www.pa.op.dlr.de/CCMVal/ SPARC Chemistry-Climate Model Validation Activity (CCMVal)]
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* [http://www.igac.noaa.gov/ACandC.php IGAC-SPARC Atmospheric Chemistry & Climate Initiative (AC&C)
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* aerosol properties and size classes (currently, only pm2p5, nucleation_mode and coarse_mode are known in the CF standard name table)
* [http://nansen.ipsl.jussieu.fr/AEROCOM/aerocomhome.html Aerosol Comparisons between Observations and Models (AeroCOM)]
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* handling of source attributions (for example "SOA from benzene" or "anthropgenic aerosol")
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* more specific descriptions of technical pecularities concerning (particle) measurements
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* description of many variables concerning (CALIPSO) satellite retrievals
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=== Pending suggestions for new AQ related CF standard names ===
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* [[Media:Pending_CF_standard_names-20111005.doc]]
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=== Discussion on CF metadata for time aggregates and AQ metrics ===
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Recently, a discussion has started on the CF mailing list, how more complex data aggregates, such as the "daily maximum 8-hour ozone concentration" can be incorporated into the CF standard metadata. The present proposal is to extend the syntax of the "cell_methods" attribute to allow multiple operations. Example '''o3.cell_methods = "time: mean (period: 8 hours) time: maximum (interval: 1 hour)".'''.
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This discussion is not closed yet, because people from other communities would like to see an alternative approach where the "original" time information could be preserved. In this proposal, one would (have to?) create an additional time axis which would carry the mean time and time bounds for the daily 8-hour intervals.

Latest revision as of 02:23, July 22, 2012

AQ CF standard names

This is the work space associated with the CF conventions description. While the actual approval process for new standard names happens exclusively via the CF mailing list, you can use these pages to prepare such discussions, monitor progress or ventilate new ideas. For additional information what this is about, please consult the main page on ESIP, the CF home page or directly the latest CF standard document or standard name table.

Discussion of standard name attributes for AirNow and RSIG variables

Brief summary: many quantities contained in either variable set have already been defined in the CF standard name table or they have close counterparts which require only simple additions to this table (for example adding another species name to the available list of "mole_fraction_of_X_in_air"). Some more discussion is needed on the following points:

  • aerosol properties and size classes (currently, only pm2p5, nucleation_mode and coarse_mode are known in the CF standard name table)
  • handling of source attributions (for example "SOA from benzene" or "anthropgenic aerosol")
  • more specific descriptions of technical pecularities concerning (particle) measurements
  • description of many variables concerning (CALIPSO) satellite retrievals

Pending suggestions for new AQ related CF standard names

Discussion on CF metadata for time aggregates and AQ metrics

Recently, a discussion has started on the CF mailing list, how more complex data aggregates, such as the "daily maximum 8-hour ozone concentration" can be incorporated into the CF standard metadata. The present proposal is to extend the syntax of the "cell_methods" attribute to allow multiple operations. Example o3.cell_methods = "time: mean (period: 8 hours) time: maximum (interval: 1 hour)"..

This discussion is not closed yet, because people from other communities would like to see an alternative approach where the "original" time information could be preserved. In this proposal, one would (have to?) create an additional time axis which would carry the mean time and time bounds for the daily 8-hour intervals.