Andreas,
Your quantity is a specific instance of the generic quantity
"amount-of-substance concentration" (SI unit: "mol/m^3"). Thus, reasonable
names for it according to
http://physics.nist.gov/Pubs/SP811/sec08.html would
be "amount-of-air concentration", "air-molecules concentration", or
"molecules-of-air concentration" -- all with the same SI unit.
I dislike names for physical quantities that incorporate the unit in them
(e.g., "mole concentration") because it can lead to cognitive dissonance if
the quantity's associated unit differs from the one in the name (e.g.,
"mole concentration" in units of "molecules/meter^3"). I accept the advice
from standards organizations like the NIST that the names of quantities
should be unit-independent (consider the quantity "kilogram fraction"
compared to "mass fraction").
I'm well aware that this runs counter to several customs.
More information can be found at the above URL.
Regards,
Steve Emmerson
On Wed, Jul 2, 2014 at 5:40 AM, <alison.pamment at stfc.ac.uk> wrote:
> Dear Andreas,
>
> This might sound like a silly question, but what do you mean by "air"? Do
> you mean just the mixture of gases or do you mean everything that might
> be found in a random sample of air, including aerosol particles and
> precipitation?
>
> If you mean strictly the gases, then I would suggest
> mole_concentration_of_gas_molecules_in_air which would have
> canonicalunits of mol m-3
> or if you want to express it as a simple number per unit volume we could
> have
> number_concentration_of_gas_molecules_in_air (m-3).
>
> If you want to include all constituents of the air parcel, then you would
> need something like
> mole_concentration_of_molecules_in_air
> or perhaps even better
> mole_concentration_of_air
> both of which would have canonical units of mol m-3.
> The name number_concentration_of_air doesn't sound very meaningful in
> English, but you could have
> number_concentration_of_molecules_in_air (m-3).
>
> Best wishes,
> Alison
>
> ------
> Alison Pamment Tel: +44 1235 778065
> NCAS/British Atmospheric Data Centre Email: alison.pamment at stfc.ac.uk
> STFC Rutherford Appleton Laboratory
> R25, 2.22
> Harwell Oxford, Didcot, OX11 0QX, U.K.
>
> >-----Original Message-----
> > From: Andreas Hilboll [mailto:lists at hilboll.de]
> > Sent: 02 July 2014 10:46
> > To: cf-metadata at cgd.ucar.edu
> > Subject: [CF-metadata] mole_concentration_of_air_in_air?
> >
> > Hi guys,
> >
> > I'm wondering how to express the air number density, i.e., the number of
> > air molecules per unit volumne (in mole cm-3), in terms of CF standard
> > names?
> >
> > -- Andreas.
> > _______________________________________________
> > CF-metadata mailing list
> > CF-metadata at cgd.ucar.edu
> > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
> --
> Scanned by iCritical.
> _______________________________________________
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>
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