[CF-metadata] Proposal for additional CF biogeochemistry attributes

From: Philip Cameronsmith <cameronsmith1>
Date: Wed, 13 May 2009 11:42:20 -0700 (PDT)

Hi All,

I respectfully disagree with using 'mole_mixing_ratio_', although I accept
we are down to the level of nitpicking.

The four CF quantities with _mixing_ratio_ all involve the ratio of
substance to medium in mass units, which is even further away from the
concept we want than mole_fraction_.

To me, there are two good alternatives:

1) Extend the use of mole_fraction in an entirely natural extension to
include the concept of a ratio of components: ie

     mole_fraction_of_X_to_Y_in_medium

2) Decide we need a new expression for the subtly different concept of the
ratio of components, in which case the obvious construct is:

     mole_ratio_of_X_to_Y_in_medium

I would be happy with either, although my personal preference would be for
option (1) mole_fraction_, since I feel it is an obvious extension, avoids
the addition of a new prefix, and the '_to_' construct clearly
distinguishes the concept of 'ratio of species' from 'ratio to the
medium'.

Best wishes,

      Philip


On Wed, 13 May 2009, olivier lauret wrote:

> Hi all,
>
> I am not sure Bruce and others received previous answer from Jonathan.
>
> I am OK with 'mole_mixing_ratio_of_nitrate_to_phosphate_in_sea_water'.
>
> Kind regards,
>
> Olivier.
>
> -----Message d'origine-----
> De?: cf-metadata-bounces at cgd.ucar.edu [mailto:cf-metadata-bounces at cgd.ucar.edu] De la part de Jonathan Gregory
> Envoy??: mercredi 13 mai 2009 09:16
> ??: cf-metadata at cgd.ucar.edu
> Objet?: [CF-metadata] Proposal for additional CF biogeochemistry attributes
>
> Dear Philip and Bruce
>
>> In the atmosphere CF has used 'mole_fraction_' to designate mole/mole
>> quantities.
>>
>> Hence, perhaps we should use
>> MOLE_FRACTION_of_nitrate_to_phosphate_in_sea_water here?
>>
>> The counter argument is that, in every existing CF std name I could find,
>> mol_fraction_ is always the mole ratio of the species to air.
>
>> Hence, I think the question boils down to: Do we want to create a new
>> prefix (ie 'mole_ratio_') for ratios of species to species (as opposed to
>> the ratio of species to medium)?
>
> Yes, I think that would be a good choice, for instance a pattern
> mole_ratio_of_X_to_Y_in_sea_water
> or perhaps
> mole_mixing_ratio_of_X_to_Y_in_sea_water
> by analogy to four existing standard names that use the phrase mixing_ratio.
>
>> (They also seem to prefer expressing oxygen concentration in
>> ml/l, by the way.)
>
> One of these four is the existing standard name
> volume_mixing_ratio_of_oxygen_at_stp_in_sea_water
> which I think is just what you want i.e. the ratio of the volume of oxygen gas
> at STP to the volume of water it is dissolved in.
>
> Best wishes
>
> Jonathan
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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
------------------------------------------------------------------------
Received on Wed May 13 2009 - 12:42:20 BST