Dear Alison,
Many thanks for this excellent idea.
You are suggesting mass_ratio_of_X_to_Y. To my knowledge we would rather
say mass_mixing_ratio. This would make the names longer, but the use of
mixing ratio is more common, I would say.
However, although I like your idea a lot, I am concerned b
Roy,
I would be very interested in using CF as a demonstration of mapping
using the additional terms from the latest SKOS: broaderThan,
narrowerThan, closeMatch, and relatedMatch. (I'm also extremely
interested in the CF ontology proposal discussed earlier, but I will
not be able to engag
Hi John,
My understanding of Standard Name 'aliases' is that they provide a deprecation
mechanism. Until the last batch of updates the relationship between the 'old'
and 'new' was exactMatch, but this changed significantly in the last update
with many of the 'replacements' being obviously sema
This seems a little artificially constrained -- make the change for a
day, then change it back, and presto, now the alias is recording a
previous version of a standard name.
But I guess that doesn't address your main point, which is that
aliases aren't intended to serve as synonyms/navigati
Dear Jonathan,
I think that "mass fraction of X in air" is equivalent to "mass mixing
ratio of X in air", "mixing ratio" alone would rather equivalent to
volume or mole mixing ratio.
If water vapor is a special case in that the humidity mixing ratio
excludes X=water from the denominator, wher
Dear Jonathan, Philip, Martin and Christiane,
Jonathan wrote:
>
> For water vapour, the common terms are (I believe) humidity mixing
ratio and
> specific humidity.
> Specific humidity means mass_fraction_of_water_vapor_in_ambient_air=
> (water vapour)/(air including water vapour), while humidity
Dear Christiane
> Maybe I have missed the recent discussion, but to my understand, the
> mixing ratio is generally defined as
> x/(sum_of_all_components_including_x), which would mean in our case the
> humidity_mixing_ratio would be equivalent to
> mass_fraction_of_water_vapor_in_ambient_air.
> Fo
Dear Jonathan and others,
I am sorry for the delay of my responses to the CF discussions. I now
sending answers to all pending messages.
In your last email you have summarized the discussion about the mass
mixing ratios:
mass_fraction_of_X_in_air
for all X and say that we are deliberately
Dear Christiane
> We do not use CF at the moment in the plume model, so for my specific
> problem our discussion is not relevant. I was just thinking that a vague
> name could lead to problems later, if the variable is used by different
> people in different ways.
Yes, I agree, it could, although
Dear Jonathan,
I think the crucial question is whether at this point you think you need to
distinguish between ambient-air and dry-air quantities. That is, do you have
both in your dataset, or do you have applications where it is essential to know
which kind a quantity was? If you do need to tel
Dear Christiane
> Actually, the volcanic plume model I have been working with was
> referrring to wet air as the water vapor ratio was very high close to the
> volcanic vent. Such situations are not common in the atmosphere, but in
> special cases, they can be. I would therefore still vote for t
Dear Martin, John, and Philip,
I would like to comment on Martin's remark
> To my knowledge, practically *all* models always refer to dry_air as the
denominator. With *all* I mean all models that don't go above altitudes
of ~80 km.
Actually, the volcanic plume model I have been working with
Dear Martin
Your arguments are reasonable and we've had this kind of discussion a few
times about what standard names are for. I agree with what you write:
> I suggest that standard names should
> be a reasonable compromise between accuracy and simplicity. We should
> definitively avoid jargon an
Dear John, Philip and Christiane,
unless mankind will burn all coal, oil and gas, water vapour is
probably the only constitutent that actually has any noticable impact on
the distinction between "X/(air including X)" and "X/(air not including
X)". To my knowledge, practically *all* models alwa
Hi Jonathan,
From an atmospheric chemistry centric position, I personally would still
prefer to use mass_fraction_of_water_vapor_in_dry_air than
humidity_mixing_ratio, but I appreciate that there are many users of CF
who would prefer humidity_mixing_ratio, and that water vapor could be a
spe
Dear Philip and Christiane
Thanks for the explanation. I appreciate that the ratio of constituent mass
to dry air mass is a sensible quantity to use in a model; I am not disagreeing
with that at all. The question is what the standard name should be. I was
confused by the proposal and as Philip als
Dear Philip,
Thank you, this is about what I meant in my email this morning to
Jonathan, but much much much better explained.
Christiane
Philip J. Cameronsmith1 schrieb:
Hi Jonathan,
I agree that 'water vapor in dry air' initially seems to make no sense.
But it is particularly useful in
Hi Jonathan,
I agree that 'water vapor in dry air' initially seems to make no sense.
But it is particularly useful in chemistry transport models that read in
meteorological data from a file (an off-line model) to use dry air in the
denominator for all of the species, and this is just the logi
Dear Alison
Ah, now I see. I found that confusing, though. If I read "fraction of A in B"
I'd assume that A is a subset of B e.g. I assume that mass fraction of fat
in cream means fat/cream, not fat/(cream-fat), and mole fraction of nitrogen
in air means nitrogen/air. If I read "mass fraction of f
Dear Philip, Jonathan and Christiane,
> >
> >> In addition, the mass fraction of water vapor in dry air is not
> zero,
> >> this is possible and used in models.
> >
> > What does it mean, then? I assume "dry air" means "air containing no
> water".
> > Can it have a non-zero mass fraction of water
On Thu, 6 Nov 2008, Jonathan Gregory wrote:
Dear Christiane
Instead of 'moist' I would suggest 'ambient'. This would be consistent
with 'ambient' aerosol.
Good idea.
In addition, the mass fraction of water vapor in dry air is not zero,
this is possible and used in models.
What does it me
Dear Christiane
> Instead of 'moist' I would suggest 'ambient'. This would be consistent
> with 'ambient' aerosol.
Good idea.
> In addition, the mass fraction of water vapor in dry air is not zero,
> this is possible and used in models.
What does it mean, then? I assume "dry air" means "air c
Dear Jonathan,
Instead of 'moist' I would suggest 'ambient'. This would be consistent
with 'ambient' aerosol.
In addition, the mass fraction of water vapor in dry air is not zero,
this is possible and used in models.
I am not sure, if 'air' means dry_air to everybody, I would assume that
s
Dear Alison et al.
I wrote
> I think we could include both of these:
>
> > >'water_vapour_mixing_ratio'
> > >'mass_fraction_of_water_vapour_in_dry_air'
>
> They are different quantities, and people should use the one which describes
> their data.
That was wrong, sorry, I wasn't thinking.
Shou
Dear Alison
I think we could include both of these:
> >'water_vapour_mixing_ratio'
> >'mass_fraction_of_water_vapour_in_dry_air'
They are different quantities, and people should use the one which describes
their data.
Best wishes
Jonathan
___
CF-meta
On Tue, 4 Nov 2008, Pamment, JA (Alison) wrote:
Dear Martin, Heinke and Jonathan,
Martin wrote:
'water_vapor_mixing_ratio'
water vapor mixing ratio of a parcel of moist air is the ratio of
the
mass of water vapor to the mass of dry air.
I think there is agreement that the existing standard
Dear Martin, Heinke and Jonathan,
Martin wrote:
> > > 'water_vapor_mixing_ratio'
> > > water vapor mixing ratio of a parcel of moist air is the ratio of
> the
> > > mass of water vapor to the mass of dry air.
> > I think there is agreement that the existing standard name
> humidity_mixing_ratio
Dear Martin and Alison
> > > water vapor mixing ratio of a parcel of moist air is the ratio of the
> > > mass of water vapor to the mass of dry air.
I think the mass fraction of water vapor in air would be the ratio of mass
of water vapor to mass of moist air. That's not quite the same. Would you
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