[CF-metadata] New standard names for atmospheric sea salt and for nitrogen deposition

Daniel Neumann daniel.neumann at io-warnemuende.de
Thu Jun 22 08:06:50 MDT 2017

Dear Alison,

Thank you for transferring the suggestions to proposal form and 
accepting most of the proposals.

 > Please could you also check that you are happy with the amendments
 > to your existing nitrogen names (discussed under proposal 13).

You wrote:
 > Okay, so I think these three names should now be as follows:
(kg m-2 s-1)
 > [...]
(kg m-2 s-1)
 > [...]
(kg m-2 s-1)
 > [...]
 > The existing names would then become aliases of the new versions. Are 
these okay?

OK, I am happy with the changes that you suggested. The new versions are 
not ambiguous anymore.


I wrote:
 > > I would suggest to keep '_chloride_dry_aerosol_particles_' instead 
of changing it to '_dry_aerosol_particles_expressed_as_chloride_'. The 
formulation '_A_expressed_as_B_' seems to appropriate in situations, in 
which (a) B is a reasonable metric for A and (b) B is an element of 
which A consists:
 > >   - '...sulfate...expressed_as_sulfur...' or
 > >   - '...organic_matter...expressed_as_carbon...' .
 > >
 > > The particulate mass concentrations (and fractions) of nitrate and 
ammonium are denoted as '_nitrate/ammonium_dry_aerosol_particles_'. 
Although nitrate and ammonium are aerosols that consist of more than one 
atom, the naming convention for other ions, such as chloride, should be 

Alison wrote:
 > The correct choice of syntax depends on what is intended by the 
name.  I would interpret 
mass_concentration_of_chloride_dry_aerosol_particles_in_air to mean the 
total mass of the aerosol particles that contain chloride (i.e. the mass 
of the chloride plus whatever else it is combined with). We do have 
quite a number of existing names like this, for example, 
atmosphere_mass_content_of_ammonium_dry_aerosol_particles. [...]
 > You are correct that we do have some existing names for mass 
concentrations and fractions of nitrate|ammonium_dry_aerosol_particles 
and thank you for drawing these to my attention. I would interpret these 
in the way I explained above i.e. referring to the total mass of the 
particles containing the nitrate or ammonium. [...]

I did not gasp that meaning of 
before. For the total mass of aerosol particles that contain chloride, I 
would have expected a standard name like 

I also did not consider this interpretation because I see problems in 
the practical application of it. While it is useful to have a standard 
name for the dry aerosol particle mass of primary particles, i.e. dust, 
primary organic aerosol and sea salt, it is difficult to apply it to 
secondary particulate mass. Ammonium, nitrate, and partly sulfate often 
are secondary compounds - they condense as ammonium nitrate or ammonium 
sulfate (form after condensation of the respective gaseous acids/bases). 
Thus, I expect that we might find these compounds at nearly every 
particle in agriculturally and industrially used areas (correct me, if I 
am wrong). Therefore, I do not see an application for a standard name, 
which describes the mass of all particles that contain ammonium. As a 
results I did not expect this standard name to mean what it should mean. 
I hope I expressed it clearly/understandably.

Alison wrote:
 > The definitions of the existing names don't make that clear which 
actually makes them rather ambiguous. I think perhaps we should add 'The 
mass is the total mass of the particles' to those definitions, as for 
the mass content names, although this is something that probably needs 
wider consultation on the mailing list before making a decision.

I agree. Could we consider to modify these standard names for 
clarification instead of just modifying the definitions? I could start a 
new thread at the mailing list "Clarifying standard names for 

Alison wrote:
 > In contrast, I would interpret 
to mean the mass of only the chloride that is contained within the dry 
aerosol particles. I had assumed you meant the mass of only the chloride 
which is why I suggested the second option, but perhaps that is 
incorrect. Please can you clarify?

Your assumption is correct. I would hesitate to introduce this 
formulation because I see a problem when we want to provide the mass of 
ammonium in dry aerosol particles expressed as nitrogen. We needed to 
call it 
I would be happy with another standard name. Would it be an alternative 
to write instead "mass_concentrations_of_particulate_chloride_in_air"?


Daniel Neumann

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

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

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