Talk:CF Standard Names - CF Standard Names - Submitted Atmospheric Chemistry and Aerosol Terms

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This page contains the email with the discussuion about the table on submitted atmospheric chemistry and aerosol terms, Version 6: 11.07.2007

Discussion launched by Christiane Textor, July 11

Dear aerosol and chemistry modellers,

I would like to ask for your comments on the standard names for the CF conventions for aerosols and chemistry, mainly concerning their sources and sinks, and optical thickness.

It is important that these names are checked by many people because they have to be understandable across communities. It would be very helpful if you could have a quick look!!

The names can be found at:

http://wiki.esipfed.org/index.php/CF_Standard_Names_-_CF_Standard_Names_-_Submitted_Atmospheric_Chemistry_and_Aerosol_Terms

In May, about 30 names have been accepted:
http://wiki.esipfed.org/index.php/CF_Standard_Names_-_Accepted_names_for_aerosols_and_chemistry
http://cf-pcmdi.llnl.gov/documents/cf-standard-names/5/cf-standard-name-table.html

THANK YOU VERY MUCH FOR YOUR TIME!

Best regards, Christiane

Comment from Mian Chin, July 12: mixed aerosols/optical thickness

Christiane,

The names are pretty clear to me, except the sulfate, nitrate, and ammonium aerosol optical depth parts: Because ammonium has to be associated with sulfate and nitrate (or other anions), it is not an independent aerosol species; I am not sure the meaning of "ammonium aerosol".

Also, I think the terms of SO2 gas phase destruction, SO2 aqueous phase destruction, (or sulfate gas phase and aqueous phase production), SO2 gas phase production, DMS gas phase destruction should be included in the "tendencies due to chemical reactions" category.

Mian

Reply from Christiane Textor, July 12

Dear Mian,

Thank you very much for your valuable comments.

Concerning the optical thickness AOT per species: in reality most aerosols are internally mixed, i.e. associated with other species, but AOT is calculated from the sum of the contributing species in most cases. This is why I have defined the names, in accordance what we had used in AeroCom.

For ionic components, it becomes even more tricky. We had e.g. sulfate optical thickness AOT in AeroCom.

What would you suggest to describe these values?


Concerning the additional names you suggested, I agree that these might be needed, but as I replied to Yves: The philosophy of the CF convention is to only add names if they are actually needed. The names I have proposed have been used in HTAP.

Thank you very much for your comments in advance.

Cheers, Christiane

Reply from Frank Dentener, July 12

Hi Mian; I understand what you say- but you'll have the same discussion with e.g. water in ambient aerosol: it can not exist without other component. It is the consequence of artificially seperating the components of an internally mixed aerosol system. I do not think that in practice it will cause problems. f

Reply from Michael Schulz, July 12

Hi Frank, Mian and especially Christiane,

As Frank said: I understand what you say. However, I would say that in practice this AOD business indeed created and will create problems. I fear even for HTAP we need to reask modellers what they really provided. So the only way (for the future) would be to elaborate on the clear definition of what the variables mean.

1) I propose that we clearly state which dry mass is associated to a given AOD. If we wish to describe the dry soluble mass in terms of salts, then we have to express that in the name.

So I think we need to propose in addition to
atmosphere_optical_thickness_due_to_sulfate_ambient_aerosol
atmosphere_optical_thickness_due_to_ammonium_ambient_aerosol
atmosphere_optical_thickness_due_to_nitrate_ambient_aerosol
atmosphere_optical_thickness_due_to_sodium_ambient_aerosol
(note: if only "sulfate" is given I would assume, that no ammonium is associated to it)

the following:
atmosphere_optical_thickness_due_to_ammonium_sulfate_ambient_aerosol
atmosphere_optical_thickness_due_to_ammonium_bi_sulfate_ambient_aerosol
atmosphere_optical_thickness_due_to_sulfuric_acid_ambient_aerosol
atmosphere_optical_thickness_due_to_ammonium_nitrate_ambient_aerosol
atmosphere_optical_thickness_due_to_sodium_nitrate_ambient_aerosol

For all these categories I propose the associated water has been either split according to volume of dry mass among aerosol components present in the soluble, mixed aerosol or according to a model derived water attribution. In any case the CF description should express the need that the sum of the species AOD should equal the total ambient AOD! However one has split the water and species. (nonlinear problems are for research papers.....)

I think it would also be needed to explain what this means:
atmosphere_optical_thickness_due_to_water_in_ambient_aerosol
To my understanding it is the difference between the total dry aerosol and the total ambient aerosol AOD.

well, well Michael

Comment from Yves Balkanski, July 12: addition of names for natural/anthropogenic components

Hello all,

You did not distinguish between the natural and the anthropogenic component. Did you ever condider doing it? If I take a file with optical depth, I would be interested to know it, would that be a subfield?

Thanks

Yves

Reply from Christiane Textor, July 12

Dear Yves,

Thank you very much for your comment! The philosophie of the CF convention is to only add names if they are actually needed. The names I have proposed have been used in HTAP, and the distinction between anthropogenic/natural was not included.

Cheers, Christiane

Comment from Arlene Fiori, July 13> NOy, POM, chemical_gross_production

Hi Christiane,

They look fine to me. A few minor points:

(1) NOy explanations could also include HONO, and add "expressed as mass of nitrogen" to be consistent with the explanations for other species. I realize it's in the name itself, but might not hurt to have it both places (also for NOx).

(2) Is tendency_of_atmosphere_mass_content_of_particulate_organic_matter_dry_ae rosol_due_to_chemical_net_production_and_emission = tendency_of_atmosphere_mass_content_of_secondary_particulate_organic_mat ter_dry_aerosol_due_to_chemical_net_production + + tendency_of_atmosphere_mass_content_of_primary_particulate_organic_matte r_dry_aerosol_due_to_emission ?

If so, it seems redundant to have all 3 but maybe I'm misunderstanding.

(3) in the "chemical_gross_production" terms, seems like "gross_chemical_production" would be a more logical ordering

Arlene --

Reply from Christiane Textor, July 12

Dear Arlene,

Thank you very much for your comments! Please find my answers below:

> (1) NOy explanations could also include HONO, and add "expressed as mass of nitrogen" to be consistent with the explanations for other species. I realize it's in the name itself, but might not hurt to have it both places (also for NOx).

Added!

> > (2) Is >tendency_of_atmosphere_mass_content_of_particulate_organic_matter_dry_aerosol_due_to_chemical_net_production_and_emission
>= tendency_of_atmosphere_mass_content_of_secondary_particulate_organic_matter_dry_aerosol_due_to_chemical_net_production
>+tendency_of_atmosphere_mass_content_of_primary_particulate_organic_matter_dry_aerosol_due_to_emission ? > > If so, it seems redundant to have all 3 but maybe I'm misunderstanding. >

You are right that the third equals the sum of the first two. Sum models do not distinghuish between prim. and sec. and this is why I also proposed the total.

> (3) in the "chemical_gross_production" terms, seems like "gross_chemical_production" would be a more logical ordering

I thought it would be better to attach the 'gross' prefix to 'production', because their are potentially other processes than chemical, e.g. biological.

Cheers, Christiane

Comment from Christiane Textor, July 13: Why 'tendency' and not 'flux'?

Hello again,

Thank you very much for your comments so far!

Michael Schulz has asked me, why I propose 'tendency' instead of 'flux' for emission, deposition and chemical production, and I would like to explain this here.

I did this because the term 'flux' is related to a change per unit area. This does apply to deposition to and emission from the surface, but not to emissions from airplanes or fires, or to the production of secondary aerosols. The term 'tendency' just means a change in time, no dimension is associated with it.

I thought it would be confusing to use for some variables the term 'flux' and for others the term 'tendency'. Therefore, I have proposed

tendency_of_atmosphere_mass_content_of_species_due_to_process

The term 'mass_content' indicates a vertical integral: "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." from the CF web site.

It would be very helpful if you could just send a short comment which solution you prefer:

      • MIXED use of 'flux' and 'tendency'
      • GENERAL use of 'tendency'

Thank you very much!

Cheers, Christiane