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

From: Jonathan Gregory <j.m.gregory>
Date: Thu, 25 Sep 2008 08:22:26 +0100

Dear Martina, Philip, et al.

New chemical constituents: Are the names proposed the ones which are used
invariably or normally for these species? Are they consistent with the choices
that have been made for other species in existing names? (I don't know enough
about this to say.) We have had previous discussions about using IUPAC names:
they have the advantage of being a separately maintained standard, but they may
be too long. In any case, we should try to avoid using different conventions
for different species. For instance, we have ethane, ethene, ethyne; ethanol is
now proposed (all IUPAC, I believe) - is "acetic" consistent with that? For
reference, I append to this email all the existing species names (in standard
names containing the word "mole" - possibly this doesn't pick up them all).

"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?

Philip commented

> 2) What is meant by 'expressed_as_carbon'? Does it mean 'mass of carbon
> contained in species, ignoring all other chemical elements'? If so, would
> it be appropriate to put this into the units instead of the standard name?

Yes, "expressed_as" means the amount of X contained in all the species,
ignoring the rest. In fact, in most of the existing names with expressed_as,
it is moles, not mass e.g.
  mole_concentration_of_diatoms_in_sea_water_expressed_as_nitrogen (mol m-3)
which means the moles of N per m3, I believe. We adopted this convention after
a lot of discussion. I think it is correct to include it in the standard name;
CF generally does not use the units for indicating quantities. CF units are
SI (or equivalent) and consistent with the udunits package.

I agree with Philip's comments about passive_ozone: passive tracers are of
course useful and need names, but it is likely we have to consider each case
carefully to find a clear name for it, because there are many kind of "passive"
in models. Could you describe what passive_ozone means in your application?

Best wishes

Jonathan


existing CF species:

alpha_hexachlorocyclohexane
ammonium
atomic_bromine
atomic_chlorine
atomic_nitrogen
benzene
bromine_chloride
bromine_monoxide
bromine_nitrate
carbon_dioxide
carbon_monoxide
carbon_tetrachloride
cfc11
cfc113
cfc113a
cfc114
cfc115
cfc12
chlorine dioxide
chlorine monoxide
chlorine_nitrate
dichlorine peroxide
dimethyl_sulfide
dinitrogen_pentoxide
ethane
ethene
ethyne
formaldehyde
gaseous_divalent_mercury
gaseous_elemental_mercury
halon1202
halon1211
halon1301
halon2402
hcc140a
hcfc22
hexachlorobiphenyl
hydrogen_bromide
hydrogen_chloride
hydrogen_cyanide
hydrogen_peroxide
hydroperoxyl_radical
hydroxyl_radical
hypobromous_acid
hypochlorous acid
inorganic_chlorine
isoprene
methane
methyl_bromide
methyl_chloride
methyl_hydroperoxide
molecular_hydrogen
nitrate
nitrate_and_nitrite
nitric_acid
nitrite
nitrogen_dioxide
nitrogen_monoxide
nitrous_oxide
organic_detritus
oxygen
ozone
peroxyacetyl_nitrate
peroxynitric_acid
phosphate
phytoplankton
propane
propene
silicate
sulfur_dioxide
toluene
total_inorganic_bromine
total_reactive_nitrogen
xylene
Received on Thu Sep 25 2008 - 01:22:26 BST