Hi Jonathan, Martin, Angelika,
These look like good additions to me :-).
Jonathan: we already have std_names without a fixed ratio, although it isn't explicit in the descriptions (eg, atmosphere_mass_content_of_anthropogenic_nmvoc_expressed_as_carbon). Indeed, this is one of the main reasons people use the 'expressed_as' concept.
I did note the tiniest inconsistency for the future. As proposed, NOx_expressed_as_NO is consistent with the current description "The phrase 'expressed_as' is used in the construction A_expressed_as_B, where B is a chemical constituent of A. It means that the quantity indicated by the standard name is calculated solely with respect to the B contained in A, neglecting all other chemical constituents of A."
However, in the future someone may want NOx_expressed_as_NO2, and NO2 is not entirely contained in NOx. To put it another way, the mass of the emission expressed as NO2 is larger than the mass of the actual NOx emission.
We can either try to tweak the definition now, or wait and until someone proposes the case above. In practice, NOx_expressed_as_NO is going to be much more common.
Best wishes,
Philip
-----------------------------------------------------------------------
Dr Philip Cameron-Smith, pjc at llnl.gov, Lawrence Livermore National Lab.
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> -----Original Message-----
> From: CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of
> Jonathan Gregory
> Sent: Thursday, January 03, 2013 6:01 AM
> To: cf-metadata at cgd.ucar.edu
> Subject: [CF-metadata] Proposal for new standard_names for biomass burning
> emissions
>
> Dear Martin and Angelika
>
> Since these names conform to existing patterns, I should think they are fine (not
> being an expert - but you are!).
>
> > Note, that the definition of emissions for nitrogen_dioxide is tricky: most
> inventories only give emissions for "NOx" (the sum of NO and NO2), and
> sometimes it is not even clear to an uninformed user if these are "expressed_as"
> nitrogen_monoxide or nitrogen_dioxide, or even nitrogen. The ratio of emitted
> NO to emitted NO2 varies by source category, and this is now sometimes taken
> into account in models.
> ...
> >
> > "nox_expressed_as_nitrogen_monoxide":
> >
> > "NOx" means a combination of two radical species containing nitrogen and
> oxygen: NO+NO2. The phrase 'expressed_as' is used in the construction
> A_expressed_as_B, where B is a chemical constituent of A. It means that the
> quantity indicated by the standard name is calculated solely with respect to the
> B contained in A, neglecting all other chemical constituents of A.
>
> I suppose that when A_expressed_as_B has been used up to now, A and B have
> been in a fixed ratio. That's not the case there. However, I think I understand the
> idea - does it mean you would express N as though it were all NO? That is
> assuming a fixed but fictitious ratio.
>
> Best wishes
>
> Jonathan
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Received on Thu Jan 03 2013 - 13:15:12 GMT
