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

Daniel Neumann daniel.neumann at io-warnemuende.de
Thu Nov 9 08:02:31 MST 2017


I forgot: Please find a detailed description of the problem -- including 
an explanatory plot -- here (login required):

https://cera-www.dkrz.de/WDCC/ui/Entry.jsp?acronym=readme_seasalt


I forgot that the following standard name types are also affected:
  - 
tendency_of_atmosphere_mass_content_of_*_dry_aerosol_particles_due_to_...
  - mass_fraction_of_*_dry_aerosol_particles_in_air

Daniel


On 09.11.2017 15:52, Daniel Neumann wrote:
> Dear List,
>
> I would like to bring this treat back to attention to finalize it in 
> the one or another way. Further below are three suggestions ((a) to 
> (c)) on how to proceed.
>
> There are standard name types:
>  - atmospheric_mass_content_of_X_dry_aerosol
>  - mass_concentration_of_X_dry_aerosol_in_air
>  - 
> atmosphere_mass_content_of_sulfate_dry_aerosol_particles_expressed_as_sulfur
>
> They are used in (a few) CMIP5, in (a few) CMIP6, in my, and, 
> probably, in a lot of other data files.
>
> The current status of discussion is that they DO NOT describe the "... 
> mass of X ..." but the "... the mass of all particles containing X 
> ...". These are quite different meanings. In practice, these standard 
> names are used with the first meaning (at least CMIP5, CMIP6, my 
> data). In practice, the second meaning is not applicable. I am not 
> aware of any data set that uses one of these standard names 'correctly'.
>
> Thus, the current status of the discussion is that the standard names 
> are generally wrongly used. What shall we do? Here are three options.
>
> ~~~~
> The standard names do not 100% fit (if interpreted literally) to the 
> variables to which they are applied.
>
> (a) Nevertheless we keep them as they are to remain consistent and to 
> avoid confusion. I volunteer to update the descriptions.
> (b) We rename all these standard names (maybe 100 by number, probably 
> more).
> (c) We keep these standard names as they are (and enforce their 
> literal meaning!) and create correct new standard names (maybe 100, 
> probably more).
> ~~~~
>
> I am in favor of (a). Least work. Does not interfere with current usage.
>
> The solution (b) would me a lot of hand work (if Batch processing of 
> CF-Standard Name list is not possible -- is it?). The solution (c) 
> would be quite bad (in my opinion): A lot of data set would not be 
> CF-compliant anymore because 'wrong' standard names were used.
>
>
> Why do I insist on finalizing this discussion: I would like to propose 
> two new standard names, which are affected by this discussion.
>
>
> Cheers,
> Daniel
>
>
>
>
> On 13.07.2017 18:23, Daniel Neumann wrote:
>> Dear Markus, Dear List,
>>
>> Thank you for your feedback.
>>
>> > 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?
>> I agree with you.
>>
>> Thus, it might be reasonable to introduce a new standard name (I like 
>> the one you suggested. My idea for a name was more complicated :-) )
>>
>> mass_concentration_of_X_in_dry_aerosol_particles_in_air
>>
>> for (partly) secondary particulate species, namely nitrate, ammonium, 
>> mercury, chloride, particulate organic matter, secondary particulate 
>> organic matter and sulfate. For these species (except for chloride) 
>> there exists already a standard name like
>>
>> mass_concentration_of_X_dry_aerosol_particles_in_air
>>
>>
>> I think (please correct me if I am wrong) that
>>
>> mass_concentration_of_X_dry_aerosol_particles_in_air
>>
>> was meant to describe the same. Maybe one could make an alias from it?
>>
>>
>> Regards,
>> Daniel
>>
>>
>>
>> On 12.07.2017 14:32, Markus Fiebig wrote:
>>> Dear Daniel,
>>>
>>> thanks for posting this again, I missed your first posting during 
>>> vacation.
>>>
>>> Coming from the observation community, a name like
>>>
>>> mass_concentration_of_X_dry_aerosol_particles_in_air
>>>
>>> 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
>>>
>>> mass_concentration_of_X_in_dry_aerosol_particles_in_air
>>>
>>> This type of name is less ambiguous to understand, and describes a 
>>> property that
>>> can in fact be observed.
>>>
>>> Best regards,
>>> Markus
>>>
>>>
>>> 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
>>> Norway
>>>
>>> Tel.: +47 6389-8235
>>> Fax : +47 6389-8050
>>> e-mail: Markus.Fiebig at nilu.no
>>> skype: markus.fiebig
>>>
>>> P Please consider the environment before printing this email and 
>>> attachments
>>> _______________________________________________
>>> CF-metadata mailing list
>>> CF-metadata at cgd.ucar.edu
>>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>>
>

-- 
Daniel Neumann

Leibniz Institute for Baltic Sea Research Warnemuende
Physical Oceanography and Instrumentation
Seestrasse 15
18119 Rostock
Germany

phone:  +49-381-5197-287
fax:    +49-381-5197-114 or 440
e-mail: daniel.neumann at io-warnemuende.de




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