[CF-metadata] CF standard names for chemical constituents and aerosols (resulting from a GRIB2 proposal)

[Philip J. Cameronsmith1]

On Thu, 25 Sep 2008, Jonathan Gregory wrote:

> Dear Martina, Philip, et al.
>
[....]
>
> "Lumped"/"total": At present, we have only two names with "total":
>  mole_fraction_of_total_inorganic_bromine_in_air
>  mole_fraction_of_total_reactive_nitrogen_in_air
> I understand "total" here to emphasise that we are considering the total of
> the mole fractions of all the species which "qualify" as inorganic bromine,
> or reactive nitrogen, species. Is that the same as what you mean by "lumped"
> e.g. in "lumped_alkanes"? Why do we need "lumped" or "total"? Would it be
> clear enough just to say mole_fraction_of_alkanes_in_air?

Hi Jonathan, Martina, et al.,

In a previous email I gave my opinion on 'lumped' vs 'total', but missed 
Jonathan's suggestion (above) to use neither.

I think it is a reasonable suggestion. I can think of no strong reason why 
not.  It certainly has the advantage of being shorter.

As a minor issue, there might be a small amount of ambiguity in the mind 
of someone reading just the standard name. For example, someone might 
think that mole_fraction_of_C4_alkanes_in_air would mean the concentration 
of n-butane and isobutane are the same, with the value of one of them 
given in the data, whereas CF would mean that the sum of them is in the 
data.  But I think this is a minor concern, and unlikely to be a problem 
in practice.

There is also the advantage with 'total' (or 'lumped') that it does help 
indicate to the reader that the standard name is for a lumped specie, 
rather than a single unique specie.  But again I think this is only a 
minor advantage.

If we made this change, would CF be able to alias total_inorganic_bromine
and total_reactive_nitrogen to remove the 'total' for consistency?

In summary, I would be happy to use either 'total' or nothing.

Best wishes,

      Philip


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Dr Philip Cameron-Smith        Atmospheric, Earth, and Energy Division
pjc at llnl.gov                   Lawrence Livermore National Laboratory
+1 925 4236634                 7000 East Avenue, Livermore, CA94550, USA
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