Standard names: Propose new names for trace gases and aerosols for use in AerChemMIP2 and CMIP7

[fmoconnor]

On behalf of the Aerosol and Chemistry Model Intercomparison Project for CMIP7, I would like to propose standard names for a number of variables for which no standard name currently exists. These are as follows:

Name: atmosphere_absorption_optical_thickness_due_to_nitrate_ambient_aerosol_particles
Units: 1
Metadata: The optical thickness is the integral along the path of radiation of a volume scattering/absorption/attenuation coefficient. The radiative flux is reduced by a factor exp(-optical_thickness) on traversing the path. A coordinate variable of radiation_wavelength or radiation_frequency can be specified to indicate that the optical thickness applies at specific wavelengths or frequencies. "Absorption optical thickness" means that part of the atmosphere optical thickness that is caused by the absorption of incident radiation. "Aerosol" means the system of suspended liquid or solid particles in air (except cloud droplets) and their carrier gas, the air itself. "Ambient_aerosol" means that the aerosol is measured or modelled at the ambient state of pressure, temperature and relative humidity that exists in its immediate environment. "Ambient aerosol particles" are aerosol particles that have taken up ambient water through hygroscopic growth. The extent of hygroscopic growth depends on the relative humidity and the composition of the particles. To specify the relative humidity and temperature at which the quantity described by the standard name applies, provide scalar coordinate variables with standard names of "relative_humidity" and "air_temperature". The specification of a physical process by the phrase due_to_process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase.

Name: tendency_of_atmosphere_mole_concentration_of_oh_due_to_chemical_production_from_O1D+H2O
Units: mol m-3 s-1
Metadata: Mole concentration means number of moles per unit volume, also called "molarity", and is used in the construction "mole_concentration_of_X_in_Y", where X is a material constituent of Y. A chemical or biological species denoted by X may be described by a single term such as "nitrogen" or a phrase such as "nox_expressed_as_nitrogen". "tendency_of_X" means derivative of X with respect to time. The specification of a physical process by the phrase "due_to_" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Chemical production" means the result of all chemical reactions within the medium (here, atmosphere) that produce a certain amount of a particular species from the medium. The chemical formula for hydroxyl is OH.

Name: surface_net_upward_mass_flux_of_methane_due_to_emission_from_freshwater_lakes
Units: kg m-2 s-1
Metadata: The surface called "surface" means the lower boundary of the atmosphere. "Upward" indicates a vector component which is positive when directed upward (negative downward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The chemical formula for methane is CH4. The mass is the total mass of the molecules. The phrase "tendency_of_X" means derivative of X with respect to time. The specification of a physical process by the phrase "due_to_" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Emission" means emission from a primary source located anywhere within the atmosphere, including at the lower boundary (i.e. the surface of the earth). "Emission" is a process entirely distinct from "re-emission" which is used in some standard names.

Name: tendency_of_atmosphere_moles_of_methane_due_to_chemical_destruction_by_hydroxyl
Units: mol m-3 s-1
Metadata: Mole concentration means number of moles per unit volume, also called "molarity", and is used in the construction "mole_concentration_of_X_in_Y", where X is a material constituent of Y. A chemical or biological species denoted by X may be described by a single term such as "nitrogen" or a phrase such as "nox_expressed_as_nitrogen". "tendency_of_X" means derivative of X with respect to time. The specification of a physical process by the phrase "due_to_" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Chemical destruction" means the result of all chemical reactions within the medium (here, atmosphere) that destroy a certain amount of a particular species from the medium. The chemical formula for methane is CH4. The chemical formula for hydroxyl is OH.

Name: surface_downward_mass_flux_of_methane_due_to_soil_biological_consumption
Units: kg m-2 s-1
Metadata: The surface called "surface" means the lower boundary of the atmosphere. "Downward" indicates a vector component which is positive when directed downward (negative upward). In accordance with common usage in geophysical disciplines, "flux" implies per unit area, called "flux density" in physics. The chemical formula for methane is CH4. The mass is the total mass of the molecules. The specification of a physical process by the phrase "due_to_" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase.

Name: tendency_of_atmosphere_mole_concentration_of_ozone_due_to_net_chemical_production
Units: mol m-3 s-1
Metadata: Mole concentration means number of moles per unit volume, also called "molarity", and is used in the construction "mole_concentration_of_X_in_Y", where X is a material constituent of Y. A chemical or biological species denoted by X may be described by a single term such as "nitrogen" or a phrase such as "nox_expressed_as_nitrogen". "tendency_of_X" means derivative of X with respect to time. The specification of a physical process by the phrase "due_to_" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Net Chemical production" means the result of "Chemical Production" minus "Chemical Destruction". "Chemical Production" refers to all chemical reactions within the medium (here, atmosphere) that produce a certain amount of a particular species from the medium. "Chemical Destruction" is the result of all chemical reactions within the medium (here, atmosphere) that destroy a certain amount of a particular species. The chemical formula for ozone is O3. The IUPAC name for ozone is trioxygen.

Name: tendency_of_atmosphere_moles_of_molecular_hydrogen_due_to_chemical_production
Units: mol m-3 s-1
Metadata: Mole concentration means number of moles per unit volume, also called "molarity", and is used in the construction "mole_concentration_of_X_in_Y", where X is a material constituent of Y. A chemical or biological species denoted by X may be described by a single term such as "nitrogen" or a phrase such as "nox_expressed_as_nitrogen". "tendency_of_X" means derivative of X with respect to time. The specification of a physical process by the phrase "due_to_" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Chemical Production" refers to all chemical reactions within the medium (here, atmosphere) that produce a certain amount of a particular species from the medium. The chemical formula for molecular hydrogen is H2.

Name: tendency_of_atmosphere_moles_of_molecular_hydrogen_due_to_chemical_destruction
Units: mol m-3 s-1
Metadata: Mole concentration means number of moles per unit volume, also called "molarity", and is used in the construction "mole_concentration_of_X_in_Y", where X is a material constituent of Y. A chemical or biological species denoted by X may be described by a single term such as "nitrogen" or a phrase such as "nox_expressed_as_nitrogen". "tendency_of_X" means derivative of X with respect to time. The specification of a physical process by the phrase "due_to_" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Chemical Destruction" refers to all chemical reactions within the medium (here, atmosphere) that destroys a certain amount of a particular species from the medium.

Thank you for considering our proposal.

Proposer's Name: Fiona O'Connor
Date: 29 August 2024

[github-actions]

Thank you for your proposal. These terms will be added to the cfeditor (http://cfeditor.ceda.ac.uk/proposals/1) shortly. Your proposal will then be reviewed and commented on by the community and Standard Names moderator.

[fmoconnor]

Three more to add, if that's okay:

Name: number_concentration_of_cloud_condensation_nuclei_at_0.2_percent_supersaturation_in_air
Units: m-3
Metadata: "Number concentration" means the number of particles or other specified objects per unit volume. The cloud condensation nuclei number concentration is the total number of aerosol particles per unit volume independent of and integrated over particle size that act as condensation nuclei for liquid-phase clouds. A coordinate variable with the standard name of relative_humidity should be specified to indicate that the property refers to a specific supersaturation of 0.2 percent with respect to liquid water. The ability of a particle to act as a condensation nucleus is determined by its size, chemical composition, and morphology.

Name: number_concentration_of_cloud_condensation_nuclei_at_1_percent_supersaturation_in_air
Units: m-3
Metadata: "Number concentration" means the number of particles or other specified objects per unit volume. The cloud condensation nuclei number concentration is the total number of aerosol particles per unit volume independent of and integrated over particle size that act as condensation nuclei for liquid-phase clouds. A coordinate variable with the standard name of relative_humidity should be specified to indicate that the property refers to a specific supersaturation of 1 percent with respect to liquid water. The ability of a particle to act as a condensation nucleus is determined by its size, chemical composition, and morphology.

Name: tendency_of_atmosphere_mass_content_of_ammonium_dry_aerosol_particles_due_to_net_chemical_production
Units: kg m-2 s-1
Metadata: "Content" indicates a quantity per unit area. The "atmosphere content" of a quantity refers to the vertical integral from the surface to the top of the atmosphere. For the content between specified levels in the atmosphere, standard names including "content_of_atmosphere_layer" are used. The mass is the total mass of the particles. "Aerosol" means the system of suspended liquid or solid particles in air (except cloud droplets) and their carrier gas, the air itself. Aerosol particles take up ambient water (a process known as hygroscopic growth) depending on the relative humidity and the composition of the particles. "Dry aerosol particles" means aerosol particles without any water uptake. The specification of a physical process by the phrase "due_to_" process means that the quantity named is a single term in a sum of terms which together compose the general quantity named by omitting the phrase. "Net chemical production" means the net result of all chemical reactions within the atmosphere that produce or destroy a particular species. "tendency_of_X" means derivative of X with respect to time. The chemical formula for the ammonium cation is NH4+.

[efisher008]

Hi Fiona @fmoconnor,

Thank you for your patience. I have now added your proposed names into the CF editor.

I can see a potential issue with the name tendency_of_atmosphere_mole_concentration_of_oh_due_to_chemical_production_from_O1D+H2O, as standard names do not generally contain symbols other than underscores (please see the discussion/explanation in this issue). I don't believe we have any names in the current table with a + symbol, this may be worth exploring but I would refer to @japamment or another member of the conventions/standard names committee would be able to comment.

Your number_concentration names look fine. We have two existing names with number_concentration and cloud_condensation_nuclei in their construction: these are number_concentration_of_cloud_condensation_nuclei_in_air and number_concentration_of_cloud_condensation_nuclei_at_stp_in_air. As it looks like you have used elements of the description of these names in the newly proposed ones, these should be straightfoward to accept.

I will update again on this soon, but in the meantime if you have any further comments or questions feel free to add to the issue.

Best wishes,
Ellie

[taylor13]

Is there some way the at_X_percent_supersaturation could be indicated outside the standard name? Perhaps a scalar coordinate or following the "threshold" approach used in some standard names. If X could be any value among dozens (or perhaps an uncountable number) of values, we'd like to avoid proliferation of standard names to account for all the values.

[taylor13]

Also, I wonder if _oh_ should be replaced with _OH_ or perhaps _hydroxyl_radical_.

[martinjuckes]

I support Karl's suggestion. We have 8 existing names referring to _hydroxyl_radical_ and none for _oh_

[fmoconnor]

@efisher008 @taylor13 @martinjuckes Thanks for your comments on the proposed standard name tendency_of_atmosphere_mole_concentration_of_oh_due_to_chemical_production_from_O1D+H2O. I agree with the suggestion to replace oh with hydroxyl_radical - this would make the name consistent with other standard names involving oh. In relation to the O1D+H2O part of the name, how about O1D_and_H2O?

Another possibility is O1D_and_H2O_reaction.

[fmoconnor]

In response to comments by @taylor13 on the proposed names number_concentration_of_cloud_condensation_nuclei_at_0.2_percent_supersaturation_in_air and number_concentration_of_cloud_condensation_nuclei_at_1_percent_supersaturation_in_air, I agree that such names open up the possibility for proliferation and are best avoided. In this case, we could make use of the existing CF name number_concentration_of_cloud_condensation_nuclei_in_air, the metadata for which suggests that a coordinate variable with the standard name of relative_humidity be specified to indicate that the property refers to a specific supersaturation with respect to liquid water. This covers what we want!

If there's agreement, I then suggest to remove the proposed names number_concentration_of_cloud_condensation_nuclei_at_0.2_percent_supersaturation_in_air and number_concentration_of_cloud_condensation_nuclei_at_1_percent_supersaturation_in_air from this issue.