[CF-metadata] Clarifying standard names for 'mass_concentration_of_*_dry_aerosol_particles'

Markus Fiebig Markus.Fiebig at nilu.no
Wed Jul 12 06:32:47 MDT 2017

Dear Daniel,

thanks for posting this again, I missed your first posting during vacation.

Coming from the observation community, a name like


doesn't make much sense beyond archiving a model output field since it doesn't
describe any quantity that could be readily observed. Also, the mass
concentration of particles containing chemical X is somewhat ill-defined. You
will find some traces of X in almost all particles of an aerosol containing X -
so where is the threshold for saying that a particle contains X?

To me, it would make much more sense to have names of the type


This type of name is less ambiguous to understand, and describes a property that
can in fact be observed.

Best regards,

Am 11.07.2017 um 21:05 schrieb Daniel Neumann:
> Dear CF-Meta Mailinglist,
> I would like to advertise my long question from two weeks ago. Maybe there
> were no replies because it was to long :-) . Excuse me if I should be wrong
> with that assumption. The basic questions are:
> What do these two standard names mean?
>   (a) mass_concentration_of_ammonium_dry_aerosol_particles_in_air
>   (b) mass_concentration_of_dry_aerosol_particles_expressed_as_ammonium_in_air
> What should be the standard name for the mass concentration of atmospheric
> particulate chloride/ammonium/nitrate/sulfate/...? Should it be like (a), like
> (b) or something else (e.g. mass_concentrations_of_particulate_ammonium_in_air)?
> Please find details on the question here:
> http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2017/059573.html
> Regards,
> Daniel
> On 27.06.2017 14:43, Daniel Neumann wrote:
>> Dear CF-Mailinglist,
>> in a recent proposal (link given below*), Alison and I discussed about the
>> naming conventions for the mass of specific aerosol particle components.
>> There seems to be clarification necessary in the descriptions and/or names.
>> [* recent proposal with discussion:
>> http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2017/059522.html, look for
>> "10. mass_concentration_of_chloride_dry_aerosol_particles_in_air (kg m-3)"]
>> Currently, there exist standard names like
>> > mass_concentration_of_ammonium_dry_aerosol_particles_in_air
>> > mass_concentration_of_dust_dry_aerosol_particles_in_air
>> > general form: mass_concentration_of_X_dry_aerosol_particles_in_air
>> which describe mass concentration of aerosol particles that contain species
>> X. Thus, this standard name describes not only the mass of species X but also
>> the mass of other species that are associated with X on particles. In the
>> past, I thought it would describe the mass of species X only. We think that
>> there is a need for clarifying this in the description of these standard names.
>> When we now want to quantify the mass of particulate X only (e.g. mass of
>> particulate chloride, mass of particulate ammonium), we could use the
>> standard name
>> > mass_concentration_of_dry_aerosol_particles_expressed_as_X_in_air
>> However, I see two problems with respect to this naming convention. First, we
>> get a not-nice name if we want to express the mass concentrations of
>> particulate ammonium in terms of nitrogen. We needed a standard name like
>> >
>> mass_concentration_of_dry_aerosol_particles_expressed_as_ammonium_expressed_as_nitrogen_in_air
>> which contains 'expressed' twice.
>> Second (but that is my personal feeling only), I use the "X_expressed_as_Y"
>> formulation only, when there is some relation from Y to X. Or in other words:
>> when Y is a reasonable measure for X.
>> > ...organic_matter_..._expressed_as_carbon...
>> > ...nox_expressed_as_nitrogen...
>> > ...phytoplankton_expressed_as_phosphorus...
>> Therefore,
>> "mass_concentration_of_dry_aerosol_particles_expressed_as_X_in_air" is not a
>> good choice for a standard name describing the mass of particulate X in my
>> opinion.
>> An alternative would be to introduce a standard name like
>> > mass_concentrations_of_particulate_X_in_air
>> > mass_concentrations_of_particulate_ammonium_in_air
>> > mass_concentrations_of_particulate_chloride_in_air
>> What is your opinion on this topic?
>> Best Regards,
>> Daniel

Dr. Markus Fiebig
Senior Scientist
Dept. Atmospheric and Climate Research (ATMOS)
Norwegian Institute for Air Research (NILU)
P.O. Box 100
N-2027 Kjeller

Tel.: +47 6389-8235
Fax : +47 6389-8050
e-mail: Markus.Fiebig at nilu.no
skype: markus.fiebig

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