Hi Jonathan,
We need to be very careful about changing meaning here. To me, 'mass_flux_of_nitrogen_as_all_nitrogen_oxides' implies that nitrogen in other forms such as ammonia/ammonium has been included in the flux. However, 'mass_flux_of_all_nitrogen_oxides_as_nitrogen' is the flux of oxidised nitrogen species stoichmetrically recalculated as nitrogen.
Using this construct we need to have the actual 'thing' followed by the 'thing' it is expressed as. 'carbon_as_carbon_dioxide' and 'carbon_dioxide_as_carbon' are two completely different things.
Cheers, Roy.
>>> Jonathan Gregory <j.m.gregory at reading.ac.uk> 10/08/06 5:30 PM >>>
Dear Christiane
> *species_as_species
> -------------------
> Jonathan proposed to always use the construction 'X_as_Y' in
> mass fluxes of molecules, and to use instead of 'X_as_X' 'X_as_such'.
> I agree and changed the table (which contains lots of 'as_such now').
I did not work out all the consequences of this! I now find that some of
the results are unclear to me as they stand in various ways, for instance:
mass_flux_of_all_nitrogen_oxides_as_nitrogen. I expected this to be the
other way round i.e.
mass_flux_of_nitrogen_as_all_nitrogen_oxides
Isn't this the mass flux of nitrogen, but the nitrogen is
delivered in various forms? That is, I expected this to be like
surface_emission_mass_flux_of_carbon_as_carbon_dioxide
which is about 6 Gt/yr integrated over the world - that's the mass of carbon,
not the mass of carbon dioxide.
mass_flux_of_sulfate_as_such_dry_aerosol: by "as such" I mean "as itself",
so I am not sure what this means exactly. Would it be sufficient to say
mass_flux_of_sulfate_as_dry_aerosol
or would that be ambiguous as to whether it was S or SO4 mass? If so perhaps
this should be
mass_flux_of_sulfate_dry_aerosol_as_such
for SO4 and
mass_flux_of_sulfur_as_sulfate_dry_aerosol
for S. This is quite complicated, isn't it. But I appreciate this distinction
needs to be drawn if it is ambiguous in practice.
> This is not necessary for mercury as it is not a molecule.
Is that really clear?
mass_flux_of_mercury
might mean the flux of Hg contained in any combination of atomic mercury,
mercury compounds, mercury aerosol, etc. If you want it to mean atomic
mercury specifically, should it not say that specifically?
mass_flux_of_non_methane_volatile_organic_compounds: Why don't these ones
need as_such? Is it never counted as a mass flux of carbon?
Why do the mole_fractions need as_such? I would have thought
mole_fraction_of_sulfur_dioxide_in_air
could only be referring to moles of SO2, not moles of S, couldn't it?
Finally, on a different subject, I'm unclear what ambient_optical_depth means,
in the optical thickness names.
Cheers
Jonathan
_______________________________________________
CF-metadata mailing list
CF-metadata at cgd.ucar.edu
http://www.cgd.ucar.edu/mailman/listinfo/cf-metadata
--
This message (and any attachments) is for the recipient only. NERC
is subject to the Freedom of Information Act 2000 and the contents
of this email and any reply you make may be disclosed by NERC unless
it is exempt from release under the Act. Any material supplied to
NERC may be stored in an electronic records management system.
Received on Mon Oct 09 2006 - 01:19:46 BST
