CF Standard Names - Construction of Atmospheric Chemistry and Aerosol Terms

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This page provides the basis for the construction of CF standard names for atmospheric chemistry and aerosols.

The concepts described here have been developed since May 2006 for the definition of the 207 standard names that are accepted by the CF community as of October 2008.

The construction of CF standard names for aerosols and chemicals originated in the work of the PRISM project (Peter van Velthoven) see PRISM Standard Name Tables, latest Version, V 1.3. They have then been further developed on this wiki page and within the CF-mailing list. Important contributions come from the participating model intercomparison projects listed on the entry page.

The CF web site provides general Guidelines for Construction of CF Standard Names. The CF standard names for aerosols and chemicals are composed of certain standard phrases and forms, following these guidelines. The concept is explained below in section 2.

At the moment, many new proposals for standard names for aerosols and chemicals are under discussion by the CF mailing list. Therefore, we (Christiane Textor with input from Martin Schultz, Heinke Hoeck, and Martina Stockhause) try to summarize the current status of work here, in order to highlight the principles and concepts we have developed so far.

A large quantity of new standard names for chemical species, or for other topics, might be necessary in the future. This potential need has triggered a discussion on more general approaches to standard name construction (Thread "a different (but perhaps unoriginal) approach to standard name construction" launched by Karl Taylor.)

Four main ideas for the construction of new standard names for chemical species have been discussed so far:

1. Definition of each chemically related standard name explicitly in the CF standard name list, and discussion of each of these names individually (current approach).
2. Definition of groups of standard names (see below) with the individual chemical species or aerosol type given as a scalar coordinate. Names for individual species would not appear any more as CF standard names. Unphysical names would not occur, but the names would not be as human-understandable any more.
3. Definition of groups of standard names (see below). Automated generation of explicit standard names based on these groups. Submit and accept all possible names, even if some of them might not have a physical meaning.
4. Definition of groups of standard names (see below). Automated generation of explicit standard names based on these groups. Experts (possibly from the AC&C model intercomparisons) review these possible names and eliminate unphysical combinations before submission to and acceptance by the CF community.

Please note that the discussions of the aerosol and chemisty names in CF should be continued on the CF mailing list, and not on this wiki. The wiki is only used here to summarize the state of such names in CF. The descriptions below could help to converge to the most efficient strategy. (Please note, that Modifications of existing CF standard names are suggested, if they do not fit in the general concepts explained below.)

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LIST OF ACCEPTED STANDARD NAMES FOR AEROSOLS AND CHEMICALS

The list of standard names for aerosol ad chemicals accepted by October 29 2008 can be found here.

CONSTRUCTION OF STANDARD NAMES FOR AEROSOLS AND CHEMICALS

Certain phrases and forms are used:

• chemical species and aerosols: describe the species
• physical quantity (generic names): describe the property of the species, and determine the unit of the variable
• processes: are used in derivatives of variables (e.g. fluxes): tendency_of_.... due_to_<process> and give the change of the species' property due to a certain process
• medium: indicates the local medium or layer within which the variable applies

These phrases and forms are combined to obtain the standard names, like for example <physical_quantity>_of_X_in_<medium tendency_of_<physical_quantity>_of_X_in_<medium>_due_to_<process> The combination of these phrases and names results in groups of Standard_Names that are given below. However, not all combinations are possible or reasonable. There are some odd names that do not fit in the general concepts. Modifications are suggested for these names in order to allow for the automatic creation of individual names from groups of CF standard names.

Phrases and forms

Chemical species and aerosols

These can be chemical species with a defined molar mass (molecules, salts, etc.) or components that do not have a defined molar mass (aerosol, biological species)
Goto to the list of chemical species and aerosols as of 29 October 2008.

Physical Quantities

angstrom_exponent [1]
optical_thickness [1]
mass_content [kg/m2]
mass_fraction [kg/kg]
mass_concentration [kg/m3]
mole_concentration [mole/m3]
mole_fraction [mole/mole]
moles [moles]
tendency_of_<Z>_due_to_<process> (with Z=physical quantity of component, in units of per s)
(Please note, that a discussion on the units might be necessary.)

Processes

dry_deposition
emission
re_emission
wet_deposition
net_production_and_emission
dry_deposition_into_stomata
<no process=total changes>

Medium

in_air
in_sea_water
in_atmosphere
in_middle_atmosphere
in_troposphere

or atmosphere used as a prefix (suggested to be changed)

Please note that 'atmosphere' denotes all phases in the atmosphere and includes for example in_air, in_cloud, in_precipiation, etc.
in_air means in the gas phase, a definition if this includes also water vapor (dry_air or wet_air?) would be needed.

Groups of Standard_Names for chemicals and aerosols

The combination of the prases and forms given above results in groups of Standard_Names for chemicals and aerosols:

atmosphere_optical_thickness_due_to_<A_ambient_aerosol>
atmosphere_optical_thickness_due_to_<A_?dry?_aerosol>
mass_fraction_of_<A_dry_aerosol>_in_air
mass_fraction_of_<A_aerosol>_in_air
mass_concentration_of_<A_?dry?aerosol>_in_air
mole_concentration_of_<X>_in_sea_water
mole_fraction_of_<G>_in_air
moles_of_<G>_in_atmosphere
tendency_of_atmosphere_mass_content_of_<X>_due_to_dry_deposition
tendency_of_atmosphere_mass_content_of_<X>_due_to_emission
tendency_of_atmosphere_mass_content_of_<X>_due_to_re_emission
tendency_of_atmosphere_mass_content_of_<X>_due_to_wet_deposition
tendency_of_atmosphere_mass_content_of_<X>_due_to_net_production_and_emission
tendency_of_atmosphere_mass_content_of_<X>_due_to_dry_deposition_into_stomata
tendency_of_atmosphere_mass_content_of_<X>_due_to_wet_deposition
tendency_of_atmosphere_mass_content_of_<X>_due_to_wet_deposition
tendency_of_moles_of_<G>_in_atmosphere
tendency_of_moles_of_<G>_in_middle_atmosphere
tendency_of_moles_of_<G>_in_troposphere

with
A=aerosol type
G=gas
X=any component
Please note that we suggest changes for the names with '?' above and also for the medium prefix 'atmosphere' to be consistent with the general concept 'in_<medium>'.

Odd names that do not fit in any group following the general concepts

atmosphere_content_of_sulfate_aerosol
optical_thickness_of_atmosphere_layer_due_to_aerosol?
mass_concentration_of_sulfate_aerosol_in_air
surface_carbon_dioxide_mole_flux

We suggest changes to modify these names, so that they would fit in the general concepts explained here and allow for the automatic creation of individual names from groups of CF standard names. These could be added using aliases.