[CF-metadata] standard name proposal for CCMVal
Dear All,
The purpose of this posting is to summarize the status so far of all the
standard names that have been proposed to meet needs of the CCMVal
project. A total of 104 names relating to atmospheric chemistry and
atmospheric dynamics have been proposed.
Mole Fraction names
The following names have attracted no discussion and are accepted:
N.B. Because of the units of mole mole-1 we assign a canonical unit of 1
(i.e. dimensionless quantity) to mole fractions in the standard name
table.
mole_fraction_of_nitrous_oxide_in_air; 1; N2O
mole_fraction_of_hydrogen_chloride_in_air; 1; HCl
mole_fraction_of_methyl_chloride _in_air; 1; CH3Cl
mole_fraction_of_methyl_bromide_in_air; 1; CH3Br
mole_fraction_of_carbon_tetrachloride_in_air; 1; CCl4
mole_fraction_of_atomic_chlorine_in_air; 1; Cl
mole_fraction_of_chlorine monoxide_in_air; 1; ClO
mole_fraction_of_dichlorine peroxide_in_air; 1; Cl2O2
mole_fraction_of_hypochlorous acid_in_air; 1; HOCl
mole_fraction_of_chlorine_nitrate_in_air; 1; ClONO2
mole_fraction_of_chlorine dioxide_in_air; 1; OClO
mole_fraction_of_hydroperoxyl_radical_in_air; 1; HO2
mole_fraction_of_hydrogen_peroxide_in_air; 1; H2O2
mole_fraction_of_atomic_nitrogen_in_air; 1; N
mole_fraction_of_dinitrogen_pentoxide_in_air; 1; N2O5
mole_fraction_of_peroxynitric_acid_in_air; 1; HNO4
mole_fraction_of_atomic_bromine_in_air; 1; Br
mole_fraction_of_bromine_monoxide_in_air; 1; BrO
mole_fraction_of_bromine_chloride_in_air; 1; BrCl
mole_fraction_of_hydrogen_bromide_in_air; 1; HBr
mole_fraction_of_hypobromous_acid_in_air; 1; HOBr
mole_fraction_of_bromine_nitrate_in_air; 1; BrONO2
mole_fraction_of_methyl_hydroperoxide_in_air; 1; CH3OOH
mole_fraction_of_hydrogen_cyanide_in_air; 1; HCN
mole_fraction_of_passive_ozone_in_air; 1; This is a tracer quantity
The following mole fraction names have been proposed for cfcs and
halons:
mole_fraction_of_cfc11_in_air; 1; CFCl3
mole_fraction_of_cfc12_in_air; 1; CF2Cl2
mole_fraction_of_cfc113_in_air; 1; CCl2FCClF2
mole_fraction_of_cfc113a_in_air; 1; CCl3CF3
mole_fraction_of_cfc114_in_air; 1; CClF2CClF2
mole_fraction_of_cfc115_in_air; 1; CClF2CF3
mole_fraction_of_halon1301_in_air; 1; CBrF3
mole_fraction_of_halon1211_in_air; 1; CBrClF2
mole_fraction_of_halon2402_in_air; 1; C2Br2F4
mole_fraction_of_halon1201_in_air; 1; CBr2F2
Regarding the chemical names for cfc, hcfc and halon species the
discussion has centred on whether IUPAC names should always be used. To
date, no firm decision has been made to adopt IUPAC nomenclature for all
CF standard names. There is a definite (and becoming more urgent) need
to agree a coherent approach to the way CF will treat chemical species
names in the future, but that discussion is probably best held
separately from that of any specific set of proposals. I will shortly
create a new ticket in the CF trac system which can be used as a place
to hold the wider discussion.
As far as the CCMVal proposals are concerned, apart from the question
regarding IUPAC nomenclature, no objections have been raised to these
names. The terms proposed, e.g. cfc11, are unique so will not give rise
to ambiguity and they are already widely in use as has been pointed out
in the discussion. IUPAC equivalences can be given in the explanation of
the names. If a decision is made subsequently to use exclusively IUPAC
(or indeed any other naming system) in CF then aliases would need to be
created for any non-conforming names. In the present circumstances, I
think that the proposed cfc and halon mole_fraction names can be
accepted for use in the standard name table.
I would like to ask for further clarification on the meaning of the
following names:
mole_fraction_of_inorganic_chlorine_in_air; 1; (Cly) Does this mean
chlorine contained in inorganic molecules plus atomic chlorine? Does it
cover a particular list of species or one that varies from model to
model?
mole_fraction_of_total_inorganic_bromine_in_air; 1; (Bry) This raises
the same questions as the chlorine name
mole_fraction_of_total_reactive_nitrogen_in_air; 1; (NOy) Again, please
can you explain this term further. I am not clear as to what species
are covered by "reactive nitrogen".
mole_fraction_of_anthropogenic_nmvoc_in_air; 1; nmvoc means non-methane
volatile organic compounds
mole_fraction_of_biogenic_nmvoc_in_air; 1;
NMVOC names have been discussed before when names were proposed for the
HTAP project. They have not yet been included in the standard name
table. The question again is what species are included in nmvoc. If
the species vary from model to model then presumably there needs to be a
way of recording in the Netcdf file which species were actually included
in any particular dataset.
Mole Burden and Tendency of Mole Burden Names
The proposed mole_burden names are:
atmosphere_nitrous_oxide_mole_burden; mol;
atmosphere_cfc11_mole_burden; mol;
atmosphere_cfc12_mole_burden; mol;
atmosphere_cfc113_mole_burden; mol;
atmosphere_cfc114_mole_burden; mol;
atmosphere_cfc115_mole_burden; mol;
atmosphere_carbon_tetrachloride_mole_burden; mol;
atmosphere_halon1301_mole_burden; mol;
atmosphere_halon1211_mole_burden; mol;
atmosphere_halon2402_mole_burden; mol;
atmosphere_halon1202_mole_burden; mol;
atmosphere_methane_mole_burden; mol;
atmosphere_carbon_monoxide_mole_burden; mol;
atmosphere_molecular_hydrogen_mole_burden; mol;
atmosphere_methyl_chloride_mole_burden; mol;
atmosphere_methyl_bromide_mole_burden; mol;
atmosphere_hcc140a_mole_burden; mol;
atmosphere_hcfc22_mole_burden; mol;
where atmosphere_X_mole_burden means the total number of moles of X in
the atmosphere.
Following on from the mole_burden names the following tendency names are
also proposed:
tendency_of_nitrous_oxide_mole_burden; mol s-1;
tendency_of_atmosphere_cfc11_mole_burden; mol s-1;
tendency_of_atmosphere_cfc12_mole_burden; mol s-1;
tendency_of_atmosphere_cfc113_mole_burden; mol s-1;
tendency_of_atmosphere_cfc114_mole_burden; mol s-1;
tendency_of_atmosphere_cfc115_mole_burden; mol s-1;
tendency_of_atmosphere_carbon_tetrachloride_mole_burden; mol s-1;
tendency_of_atmosphere_halon1301_mole_burde; mol s-1;
tendency_of_atmosphere_halon1211_mole_burden; mol s-1;
tendency_of_atmosphere_halon2402_mole_burden; mol s-1;
tendency_of_atmosphere_halon1202_mole_burden; mol s-1;
tendency_of_atmosphere_methane_mole_burden; mol s-1;
tendency_of_troposphere_methane_mole_burden; mol s-1;
tendency_of_middle_atmosphere_methane_mole_burden; mol s-1;
tendency_of_atmosphere_carbon_monoxide_mole_burden; mol s-1;
tendency_of_troposphere_carbon_monoxide_mole_burden; mol s-1;
tendency_of_middle_atmosphere_carbon_monoxide_in_air; mol s-1;
tendency_of_atmosphere_molecular_hydrogen_mole_burden; mol s-1;
tendency_of_troposphere_molecular_hydrogen_mole_burden; mol s-1;
tendency_of_middle_atmosphere_molecular_hydrogen_in_air; mol s-1;
tendency_of_atmosphere_methyl_chloride_mole_burden; mol s-1;
tendency_of_troposphere_methyl_chloride_mole_burden; mol s-1;
tendency_of_middle_atmosphere_methyl_chloride_in_air; mol s-1;
tendency_of_atmosphere_methyl_bromide_mole_burden; mol s-1;
tendency_of_troposphere_methyl_bromide_mole_burden; mol s-1;
tendency_of_middle_atmosphere_methyl_bromide_mole_burden; mol s-1;
tendency_of_atmosphere_hcc140a_mole_burden; mol s-1;
tendency_of_troposphere_hcc140a_mole_burden; mol s-1;
tendency_of_middle_atmosphere_hcc140a_mole_burden; mol s-1;
tendency_of_atmosphere_hcfc22_mole_burden; mol s-1;
tendency_of_troposphere_hcfc22_mole_burden; mol s-1;
Firstly, the chemical species names are the same as those for the
mole_fraction proposals which have been accepted.
Secondly, if the term "mole_burden" is accepted for use, then the
construction of the tendency names follows directly and both these sets
of names could be accepted together.
This brings me to the outstanding question regarding all these names,
which is the adoption of the "burden" term itself. This has given rise
to a considerable amount of debate on the mailing list and at present
opinion is divided.
There was some discussion of an alternative to using "burden" by
describing the quantities as area integrals:
area_integral_of_atmosphere_X_mole_content with use of cell_methods to
express the fact that area is the entire globe. However, it was
generally agreed that this is not the way to proceed. The remaining
'for' and 'against' arguments can be summarised as follows:
'For' the adoption of "burden":
* "Burden" is used and defined in the IPCC AR4 report which is intended
to be read by both experts and non-experts. It is therefore widely
understood and its use in standard names will aid those searching for
the data.
* It allows names to be constructed with a parallel syntax to existing
"content" names. "Content" had to be defined as a per unit area
quantity for use in CF and "burden" could also have a clearly defined
meaning that is consistent for all CF standard names. The CF definition
of burden would be the total amount of substance contained in the full
depth of the atmosphere and over the entire globe.
'Against' the adoption of "burden":
* "Burden" is also sometimes used to mean the column integral of an
amount, e.g., column mass, and its use to mean a global integral could
therefore lead to confusion.
* An alternative syntax has been proposed: "moles_of_X_in_atmosphere"
where X is the name of the chemical species. This syntax is as concise
as the proposed "burden" syntax and avoids the need to define any new
terminology in standard names.
N.B. If the alternative suggestion is adopted the tendency names would
then need to be modified to have the syntax:
tendency_of_moles_of_X_in_atmosphere.
The various viewpoints have been discussed at some length and no new
points have been raised on the mailing list in recent days. However, we
have not yet arrived at a consensus view. Among those expressing a
view, opinion is currently divided along the following lines:
In favour of adopting "burden": Martin, Veronika
Against adopting "burden": Christiane, Karl
Willing to accept majority decision (but tending to lean against
adopting "burden": Jonathan, Philip
I have sought here to represent the current situation as fairly as
possible. If I have unfairly represented anyone's views I trust that
you will correct me.
My own view (which is just one vote, like all the others) is against the
adoption of "burden" because of the possibility of confusion with column
integrals. Personally, I think that avoiding ambiguity is one of the
most important considerations when constructing new standard names. If
a term is widely used in the literature with two distinct meanings I
think that confusion will inevitably arise.
Taking all the above points into consideration, I think the weight of
opinion is currently against adopting "burden" as a term in standard
names. However, Veronika and Martin have given reasoned arguments as to
why the term should be adopted. In order to make further progress on
this issue within a reasonable timescale I would like first to put a
question to Martin and Veronika: would you be willing to accept the
majority view and adopt the "moles_of_X_in_atmosphere" syntax for
standard names? Within CCMVal you would of course still be free to
agree the use of a long_name attribute using "burden". If you feel that
this is an acceptable solution, the names could be agreed immediately
and included in the next update to the standard name table. If,
however, your preference is still to use "burden" in the standard names,
I think the sensible course of action now would be to call on the
members of the standard names committee to comment and reach a decision
on whether to adopt the term. Please note that the committee's decision
would be final.
Dynamical Names
The following name is already in the standard name table:
tendency_of_eastward_wind_due_to_gravity_wave_drag; m s-2;
I think it is worth expanding the explanation to point out the
relationship between this name and the names proposed for the components
that contribute to the overall gravity wave drag.
The following names have attracted no discussion and are accepted:
northward_heat_flux_due_to_eddy_advection; W m-2;
northward_eliassen_palm_flux; m3 s-2; "Eliassen Palm flux" is a widely
used vector in the meridional plane, and the divergence of this flux
appears as a forcing in the Transformed Eulerian mean formulation of the
zonal mean zonal wind equation.
upward_eliassen_palm_flux; m3 s-2;
tendency_of_eastward_wind_due_to_eliassen_palm_flux_divergence; m s-2;
"Eliassen Palm flux" is a widely used vector in the meridional plane,
and the divergence of this flux appears as a forcing in the Transformed
Eulerian mean formulation of the zonal mean zonal wind equation. Thus,
"eastward_wind" here will generally be the zonally averaged eastward
wind.
northward_transformed_eulerian_mean_velocity; m s-1;
eastward_transformed_eulerian_mean_velocity ; m s-1;
tendency_of_eastward_wind_due_to_orographic_gravity_wave_drag; m s-2;
Component of gravity wave drag due to orographic waves.
tendency_of_eastward_wind_due_to_nonorographic_gravity_wave_drag; m s-2;
Component of gravity wave drag due to non-orographic gravity waves.
upward_flux_of_eastward_momentum_due_to_orographic_gravity_waves; Pa;
Zonal orographic gravity wave stress (momentum flux).
upward_flux_of_eastward_momentum_due_to_nonorographic_eastward_gravity_w
aves; Pa;
eastward_momentum indicates the component of the momentum which is being
transported, eastward_gravity_waves indicates the class of gravity waves
included, with eastward referring to the phase speed of the waves. There
is thus no obvious redundancy here, though there is a tendency in the
specialist community to do away with one "eastward" when referring to
this quantity, since gravity waves with eastward phase speeds only carry
eastward momentum.
upward_flux_of_eastward_momentum_due_to_nonorographic_westward_gravity_w
aves; Pa;
tendency_of_eastward_wind_due_to_numerical_artefacts; m s-2; The actual
tendency of the eastward wind will include a variety of numerical and
diffusive effects: this variable is designed to allow the momentum
budget to be closed.
dynamic_tropopause_potential_temperature; K; The dynamical tropopause is
very useful for interpreting the dynamics of the upper troposphere and
lower stratosphere. As with regions in the previous section, it will be
useful to have a description of the dynamical tropopause definition, as
there are variations in the scientific literature. We would propose to
give the variable an attribute "surface" containing the name of a global
attribute which describes the surface used.
The following name has not received much discussion since the proposals
were posted to the list:
mean_age_of_stratospheric_air or age_of_stratospheric_air.
However, this name did prompt quite a lot of debate in an email exchange
that took place while the proposals were under development. The first
option, mean_age_of_stratospheric_air, is the one preferred by the
CCMVal community. My understanding is that the term is widely used in
the stratospheric literature to mean the time since an air parcel was
last in contact with the troposphere, and so it is not the same as a
residence time. The inclusion of the word "mean" in a standard name
would not generally be acceptable because "mean" is a term that would
normally be used as a cell_method to describe statistical processing
within cell boundaries. However, my understanding is that in this
instance, the word "mean" does not imply that any averaging has taken
place within the cell bounds - rather it refers to the mean time taken
for air parcels to reach their current location by various transport
mechanisms from their "source" region. The term "age of air" is
generally used in the stratospheric literature to refer to the overall
distribution of transport times for air parcels reaching a particular
location. I hope that someone will correct me if I have misunderstood.
I have given this name a lot of thought, and while I appreciate that
"mean" is not being used in the same sense as in cell_methods I confess
to feeling uncomfortable about including it in the standard name. I am
concerned that it may set a precedent for allowing other "non-standard"
ways of using statistical terms into the standard names. A possible
solution might be to have some way of defining a time axis as "time
since contact with source region" so that we could then use
"cell_methods: mean" along that axis and a standard name of
"age_of_air". However, I think that this would need a modification to
the conventions to allow a new type of time axis and I wonder if that is
just adding extra complication for the sake of one standard name. I
would welcome further views on this particular name.
Best wishes,
Alison
------
Alison Pamment Tel: +44 1235 778065
NCAS/British Atmospheric Data Centre Fax: +44 1235 446314
Rutherford Appleton Laboratory Email: J.A.Pamment at rl.ac.uk
Chilton, Didcot, OX11 0QX, U.K.
Received on Wed Mar 05 2008 - 21:00:04 GMT
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