Dear Alison, Martin and Markus,
Thank you for your suggestions. Please find mine below.
2. Definitions of aqueous and gaseous phase chemistry
ok with your definitions
3. Number concentrations
A explained by Markus it is the same for Ambient and Dry aerosol.
So unless we really need to indicate "dry" or "ambient" for consistency
with other names
I agree with his proposition :
number_concentration_of_pm10_aerosol_particles_in_air;
number_concentration_of_pm2p5_aerosol_particles_in_air
Otherwise, I am also fine with your proposition to use
"dry_aerosol_particles" instead of aerosol_particles
4. Particulate organic matter
Some proposals use the expression "particulate_organic_matter", e.g.,
mass_fraction_of_particulate_organic_matter_dry_aerosol_particles_expressed_as_carbon_in_air
whereas in other cases, e.g.
mass_fraction_of_pm2p5_primary_organic_matter_dry_aerosol_particles_in_air , the term
'particulate' is omitted from the species. While it is true that referring to
'particulate_organic_matter' and 'aerosol_particles' in the same name does sound somewhat
repetitive, we need to standardize on a single approach to these names.
Referring to 'particulate_organic_matter' and 'aerosol_particles' in the
same name was not the issue.
In the second case 'particulate' was omitted because "pm" (in pm10 or
pm2p5) already means "particulate matter"
*but yes, I agree :* we can have (even three) repetitions, if it makes
things more consistent and allows to keep identifying the "POM" name.
5. Mass flux of ammonia
[..]
Following the usual construction of standard names, "net_downward_mass_flux" would be defined as
downward_mass_flux minus upward_mass_flux with a sign convention of downwards positive, as required by your definition.
Therefore, I think the correct name should simply be "surface_net_downward_mass_flux_of_ammonia". I don't
think we need the "bidirectional_surface_exchange" qualifier as it is already implied by the use of
"net".
As for the already existing standard name for
CO2surface_net_downward_mass_flux_of_carbon_dioxide_expressed_as_carbon_due_to_all_land_processes
<javascript:void(0)>
we need to specify which process(es) we refer to. In this case we only refer to
exchange between atmosphere and biosphere through stomata and soil surfaces.
For those who do not know the issues, the 'bidirectional' exchange indicator
will give some clue where to search in the literature to what is meant by it
(see for instance:http://onlinelibrary.wiley.com/doi/10.1029/2009JD013589/full)
So, I would suggest to keep"bidirectional_surface_exchange"*
*
6) Fixed lifetime name.
[...]
I would suggest as a simpler alternative that a scalar coordinate variable
could be used to give the tracer lifetime - we could then introduce a new
standard name of tracer_lifetime. The requirement to include the coordinate
variable could be part of the definition of the name.
Regarding the name itself, I am not clear what is meant by "CO-like tracer".
I am also unsure as to whether "carbon_monoxide" or "synthetic_tracer" is the
best way to label the species in these circumstances.
Please can you explain a bit more.
*
*
By "synthetic_tracer" we mean a passive atmospheric tracer that is used to study the
atmospheric transport and deposition. By "CO-like tracer" we mean a gaseous tracer which
lifetime is fairly similar to that of CO. Now, if you don't know the lifetime of CO, this
attributeis indeed not really useful.
*So I agree to** remove it and to use a** scalar coordinate variable as
suggested.*
Regarding the name itself, we suggest*"artificial_tracer"* instead of
"synthetic_tracer" (which suggests that it has been synthesised and exists).
Martin, would you agree?
With my best regards
Brigitte
On 11/25/2014 2:31 PM, Markus Fiebig wrote:
Dear Alison,
thanks for a great job on keeping the CF names consistent and keeping the ball
rolling!!!
I agree with Martin, I think your suggestions make lots of sense. I hesitated a
little at first concerning your proposal of mentioning particles twice in some
names (PM - particulate matter, POM - particulate organic matter, together with
aerosol_particles), but found your argument convincing. It is good practise to
keep established terms together. This will make life easier for search
algorithms and other applications that need to parse the individual parts of
standard names. You had one point where you wanted some comments specifically
from my side:
3. Number concentrations
The proposed number_concentration names don't specify the type of aerosol:
number_concentration_of_pm10_in_air;
number_concentration_of_pm2p5_in_air.
Do these refer to dry or ambient aerosol? To be consistent with the other names
we need something like
number_concentration_of_pm10_dry_aerosol_particles_in_air.
For the number concentration, it makes no significant difference whether the
aerosol is dry or at ambient humidity. Let me explain that. The particle number
concentration in atmospheric aerosol is dominated by particles smaller than
about 800 nm. Letting these particles grow by uptake of humidity won't change
their number, only their size. That means, if you apply a size cut, e.g. PM10,
some particles will grow out of this size range when going from dry state to
ambient state. However, since there are very few particles by number in the
range around 10µm, this effect isn't measurable, it is only of theoretical
relevance. For comparison, another systematic uncertainty in the above name
definition is the use of the PM10 size cut, which refers to 10µm aerodynamic
particle diameter. Most models use the spherical equivalent geometric particle
diameter. When going from there to the aerodynamic diameter, you need
assumptions on particle density and shape. This, even theoretically, unavoidable
systematic uncertainty in the above name definition is of the same order as the
one caused by going from dry to ambient aerosol state. I would thus for
practical reasons propose a structure like:
number_concentration_of_pm10_aerosol_particles_in_air
thus avoiding an apparent precision in the definition that can't be achieved. If
desired, we can add the essence of this discussion as a comment in the standard
name definition.
I'm presently working on a revised version of my proposal that will reflect your
conclusions.
Best regards,
Markus
Am 21.11.2014 um 13:18 schrieb [email protected]:
Dear Brigitte, Markus and Martin,
I have reviewed the discussion of all the HTAP names proposed by Brigitte at
the beginning of this year. This is in preparation for making an update to the
standard name table. I am also in the process of reviewing Markus Fiebig's own
proposals (see
http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2013/056946.html and follow
up posts) as the discussions of the two sets of names overlap. I will post
later today about Markus' names.
I have given my detailed comments on the HTAP names below. Due to the large
number of proposals for new names and amendments to existing names I have not
listed them all individually in this email. The full list of names affected by
Brigitte's proposals can be viewed at
http://cfeditor.ceda.ac.uk/proposals/1?status=active&namefilter=&proposerfilter=Brigitte+Alison&descfilter=&unitfilter=&yearfilter=&filter+and+display=Filter
which shows them as they currently appear in the CF names editor. Names with an amber title bar are
accepted for publication and will appear in the next version of the standard name table. Names with a
title bar that appears greenish/brownish (depending on your display screen) are still under discussion.
Below the title bar of each name and at the right of the screen you will also see a coloured label
which indicates whether the proposal relates to a new name, creation of an alias (term change), or an
updated definition.
I intend to publish an update to the standard name table within the next week,
concentrating on aerosol names. I will then begin preparation of another update
which will focus mainly on remote sensing names, but will also include some
other, smaller sets of proposals that have been agreed recently.
1. Summary of status of HTAP proposals
89 of 103 proposals for new names are accepted for publication; 2 others can be
accepted without change to the name if my suggestions to modify the definitions
can be agreed; 9 need some minor amendments to the names themselves and 3 need
further clarifications of the definitions.
All 138 existing aerosol names have been reviewed and aliases created to change "aerosol" to
"aerosol_particles" in the vast majority of cases. This was agreed in the overlapping discussions of Markus' and
Brigitte's proposals. In addition, the definition of all aerosol names has been corrected to reflect the "text book"
definition as supplied by Markus. The text now reads " "Aerosol" means the system of suspended liquid or solid
particles in air (except cloud droplets) and their carrier gas, the air itself."
The definitions of 32 existing nmvoc (non methane volatile organic compound) names have been updated. The
expanded text is as follows: " "nmvoc" means non methane volatile organic compounds;
"nmvoc" is the term used in standard names to describe the group of chemical species having this
classification that are represented within a given model. The list of individual species that are included in
a quantity having a group chemical standard name can vary between models. Where possible, the data variable
should be accompanied by a complete description of the species represented, for example, by using a comment
attribute."
Aliases have been created for 18 existing "black_carbon" names to change to using
"elemental_carbon" for consistency with the new names. For the moment I have not changed two black carbon
optical names (I will send a separate email about these). In addition, the definitions of 23 existing particulate
organic matter names have been changed to refer to "elemental carbon" instead of "black carbon".
2. Definitions of aqueous and gaseous phase chemistry
For the standard name
tendency_of_atmosphere_mass_content_of_sulfate_dry_aerosol_particles_due_to_aqueous_phase_net_chemical_production, you
provided a brief definition of aqueous phase chemical production: " aqueous phase (fog and clouds) is meant as
opposed to gaseous phase." I suggest expanding this for clarity and consistency with the existing "net
chemical production" definition as follows:" "Aqueous phase net chemical production" means the net
result of all aqueous chemical processes in fog and clouds that produce or destroy a species, distinct from atmospheric
chemical processes in the gaseous phase."
Is this OK? The name itself is fine.
Similarly, for the standard name
tendency_of_atmosphere_mass_content_of_sulfate_dry_aerosol_particles_due_to_gaseous_phase_net_chemical_production,
I suggest amending the wording of your gaseous_phase definition as follows:" "Gaseous
phase net chemical production" means the net result of all gaseous chemical processes in the
atmosphere that produce or destroy a species, distinct from chemical processes in the aqueous
phase."
Is this OK? The name itself is fine.
3. Number concentrations
The proposed number_concentration names don't specify the type of aerosol:
number_concentration_of_pm10_in_air;
number_concentration_of_pm2p5_in_air.
Do these refer to dry or ambient aerosol? To be consistent with the other names
we need something like
number_concentration_of_pm10_dry_aerosol_particles_in_air.
4. Particulate organic matter
Some proposals use the expression "particulate_organic_matter", e.g.,
mass_fraction_of_particulate_organic_matter_dry_aerosol_particles_expressed_as_carbon_in_air
whereas in other cases, e.g.
mass_fraction_of_pm2p5_primary_organic_matter_dry_aerosol_particles_in_air , the term
'particulate' is omitted from the species. While it is true that referring to
'particulate_organic_matter' and 'aerosol_particles' in the same name does sound somewhat
repetitive, we need to standardize on a single approach to these names.
'Particulate_organic_matter' is often abbreviated to 'POM', which is widely
used in literature, and this suggests to me that we should retain it in the
species name for ease of identification. See for example the US EPA environment
dictionary
http://www.ecologydictionary.org/PARTICULATE_ORGANIC_MATTER_%28POM%29 . There
are 44 existing particulate_organic_matter standard names.
The term 'aerosol_particle' was discussed at length in both this thread and Markus'. It
was introduced to distinguish between "aerosol" meaning the particulate
component plus its carrier gas and the particulate component alone.
To ensure consistency with the definitions of both phrases, and despite the
apparent repetitiveness, I think that all the organic matter aerosol proposals
should include both the particulate_organic_matter and aerosol_particle
phrases. I have accepted those proposals that do use both phrases and suggest
that the remainder be altered to follow the same pattern.
Thus the following six names are accepted:
tendency_of_atmosphere_mass_content_of_particulate_organic_matter_dry_aerosol_particles_due_to_emission
tendency_of_atmosphere_mass_content_of_secondary_particulate_organic_matter_dry_aerosol_particles_due_to_emission
tendency_of_atmosphere_mass_content_of_particulate_organic_matter_dry_aerosol_particles_expressed_as_carbon_due_to_emission
tendency_of_atmosphere_mass_content_of_particulate_organic_matter_dry_aerosol_particles_expressed_as_carbon_due_to_dry_deposition
endency_of_atmosphere_mass_content_of_particulate_organic_matter_dry_aerosol_particles_expressed_as_carbon_due_to_wet_deposition
mass_fraction_of_particulate_organic_matter_dry_aerosol_particles_expressed_as_carbon_in_air
The following 6 remain 'under discussion' and I propose that for consistency
they should be amended as shown:
CHANGE
mass_fraction_of_pm2p5_primary_organic_matter_dry_aerosol_particles_in_air
TO
mass_fraction_of_pm2p5_primary_particulate_organic_matter_dry_aerosol_particles_in_air
CHANGE
mass_fraction_of_pm2p5_organic_matter_dry_aerosol_particles_expressed_as_carbon_in_air
TO
mass_fraction_of_pm2p5_particulate_organic_matter_dry_aerosol_particles_expressed_as_carbon_in_air
CHANGE
mass_fraction_of_pm2p5_organic_matter_dry_aerosol_particles_in_air
TO
mass_fraction_of_pm2p5_particulate_organic_matter_dry_aerosol_particles_in_air
CHANGE
mass_fraction_of_pm10_organic_matter_dry_aerosol_particles_in_air
TO
mass_fraction_of_pm10_particulate_organic_matter_dry_aerosol_particles_in_air
CHANGE
mass_fraction_of_pm10_organic_matter_dry_aerosol_particles_expressed_as_carbon_in_air
TO
mass_fraction_of_pm10_particulate_organic_matter_dry_aerosol_particles_expressed_as_carbon_in_air
CHANGE
mass_fraction_of_pm10_primary_organic_matter_dry_aerosol_particles_in_air
TO
mass_fraction_of_pm10_primary_particulate_organic_matter_dry_aerosol_particles_in_air
5. Mass flux of ammonia
The name surface_net_downward_mass_flux_of_ammonia_due_to_bidirectional_surface_exchange was proposed
with definition: "Bidirectional surface exchange" is the exchange of a particular species
between the atmosphere and biosphere as simulated by bidirectional surface flux models.
"Downward" indicates a vector component which is positive when directed downward."
Following the usual construction of standard names, "net_downward_mass_flux" would be defined as
downward_mass_flux minus upward_mass_flux with a sign convention of downwards positive, as required by your definition.
Therefore, I think the correct name should simply be "surface_net_downward_mass_flux_of_ammonia". I don't
think we need the "bidirectional_surface_exchange" qualifier as it is already implied by the use of
"net".
5) Fixed lifetime name.
This proposal started life as two names:
mole_fraction_of_carbon_monoxide_with_lifetime_of 25_days_in_air and
mole_fraction_of_carbon_monoxide_with_lifetime_of 50_days_in_air. Martin
Schultz suggested condensing these into a single name such as
mole_fraction_of_synthetic_tracer_with_fixed_lifetime_in_air to be used with a new
attribute tracer_lifetime. At a later stage the name seems to have changed again to
mole_fraction_of_carbon_monoxide_with_fixed_lifetime_in_air, again with a tracer_lifetime
attribute. The only suggested definition for this name is to require a comment attribute
containing text such as "CO-like tracer with simple exponential decay loss term and
a lifetime of 25 days."
I think it is sensible to use one name for this quantity, however I'm not sure
that introducing a new attribute is the best approach. If it is to be part of
the CF conventions, a new attribute would require modification to the
conventions document, rather than simply an addition to the standard name
table. I would suggest as a simpler alternative that a scalar coordinate
variable could be used to give the tracer lifetime - we could then introduce a
new standard name of tracer_lifetime. The requirement to include the coordinate
variable could be part of the definition of the name.
Regarding the name itself, I am not clear what is meant by "CO-like tracer". I am also unsure as to
whether "carbon_monoxide" or "synthetic_tracer" is the best way to label the species in
these circumstances. Please can you explain a bit more.
7. Names needing further definition
Two new proposals were added at the end of the discussion: (see
http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2014/057372.html).
canopy_resistance_to_ozone_dry_deposition (m-1 s)
" The "canopy_resistance" is the resistance of a compound to uptake by the
vegetation canopy. It varies both with the surface and the chemical species or physical state (gas
or particle)."
aerodynamic_resistance (m-1 s)
"The "aerodynamic_resistance" is the resistance to mixing through the boundary
layer toward the surface by means of the dominant
process, turbulent transport."
I am not very familiar with either of these quantities and no comments have
been received on these proposals. A quick internet search suggests that both
terms are in wide use in the literature.
My (brief) research revealed that aerodynamic_resistance is sometimes termed "aerodynamic
drag" which is more similar to existing standard names for heat, momentum and gravity wave
drag. Perhaps "aerodynamic_drag" would therefore be more appropriate for this name? (I
don't have a strong opinion either way). If it is a resistance to downward turbulent transport,
then presumably that refers to transport of aerosol particles? Perhaps we should also put that in
the name to make it more self explanatory, e.g.,
aerodynamic_drag_on_turbulent_deposition_of_aerosol_particles or
resistance_to_turbulent_deposition_of_aerosol_particles_due_to_aerodynamic_drag. These are just
suggestions and I'd welcome other opinions. Regarding the definition, it appears that there are a
number of different formulae for this quantity (see for example the first paragraph of
http://agsys.cra-cin.it/tools/evapotranspiration/help/Aerodynamic_resistance.html).
Does this proposal relate to any particular formulation? If so, we should
provide a reference in the definition.
Regarding the canopy resistance name, could it be reworded to
canopy_resistance_to_downward_flux_of_ozone_due_to_dry_deposition? Perhaps this
more clearly relates the quantity to other atmospheric names? I don't know if
that is useful and again it is just a suggestion. Also, if there is a
particular formula or reference for this quantity we should include it in the
definition.
That concludes my somewhat lengthy comments! If we can agree any of the "under
discussion" names over the next two or three working days then they can also be
accepted in time for inclusion in the upcoming standard name table update.
Best wishes,
Alison
------
Alison Pamment Tel: +44 1235 778065
NCAS/British Atmospheric Data Centre Email: [email protected]
STFC Rutherford Appleton Laboratory
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.
--
Dr. Markus Fiebig
Senior Scientist
Dept. Atmospheric and Climate Research (ATMOS)
Norwegian Institute for Air Research (NILU)
P.O. Box 100
N-2027 Kjeller
Norway
Tel.: +47 6389-8235
Fax : +47 6389-8050
e-mail: [email protected]
skype: markus.fiebig
P Please consider the environment before printing this email and attachments
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Commission, Joint Research Centre, Institute for Environment and
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2749 I-21027 Ispra (VA), Italy Tel: +390332786704 Fax: +390332785837 Tel
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