Hi Christine,
This is real progress. My problem with 'surface_emission_mass_flux' is that to me the word 'emission' is associated with pollution/anthropogenic input. Do you mean 'mass_flux_from_surface_to_atmosphere' where surface is land or sea?
The definition of aerosol you give is just what I needed to clarify (and correct a misunderstanding on my part - I thought aerosol was only liquid in gas). Maybe it is so well understood in the domain that it doesn't need stating. However, I think where the standard name includes and acronym like pm10 then that needs to be spelled out in the description as has been done for NOx and NOy. This is aslo true of non-standard nomenclature like the the mercury.
I noticed a small error in the definitions of your latest list ('usig' for 'using')
Cheers, Roy.
>>> Christiane Textor <christiane.textor at aero.jussieu.fr> 9/26/2006 6:01 pm >>>
Dear Jonathan, Roy, and others,
I agree that it is important not to use the jargon of in a specific
field of research for the standard names. Comments from people of other
domains are 'needed' now, because the standard names I proposed are
indeed the results of extensive discussion within the atmospheric
chemistry/aerosol community, see also the wiki page
http://wiki.esipfed.org/index.php/Air_Quality/Chemistry_Naming_Conventions
But how to distinguish jargon from real definitions? E.g., in our
community the definition of an aerosol is very clear, but maybe there is
no official definition. Where can I find such official definitions?
I have updated the list of names according to your previous emails, see
attachment and
http://wiki.esipfed.org/index.php/CF_Standard_Names_-_Proposed_names_for_TF_HTAP
Here my reponses to Roy's comments:
mercury_0, mercury_2: I agree, but I am not expert here myself. I have
contacted a colleague.
surface_emission_mass_flux
what is wrong with this?
it means the mass flux of emissions at the surface... ?
Their is a clear definition of what aerosol is:
A gaseous suspension of fine solid or liquid particles.
So it can be both, dependent on the environmental conditions.
'pm10' and 'pm2p5'
These are common in aerosol research and legislation:
PM stands for particulate matter suspended in air.
PM followed by a number refers to all particles with a certain maximum
size (aerodynamic diameter). All smaller particles are included.
PM0.1 is particulate matter with an aerodynamic diameter of up to 0.1
?m, referred to as the ultrafine particle fraction.
PM2.5 is particulate matter with an aerodynamic diameter of up to 2.5
?m, referred to as the fine particle fraction (which per definition
includes the ultrafine particles).
PM10 is particulate matter with an aerodynamic diameter of up to 10 ?m,
i.e. the fine and coarse particle fractions combined.
Please find detailed reponses to Jonathan's comments below:
>
> * The construction X_as_Y seems fine to me, to indicate that you mean X when it
> comes as a constituent of Y. But it some cases I wonder if it is really
> necessary. What is meant by ammonium_as_ammonium?
In our community, the mass of molecules like NH4 (or SO4) are sometimes
given as N (or S). To avoid this ambiguity, I have added
ammonium_as_ammonium or sulfate_as_sulfate.
>
> * You have organic_carbon_as_particulate_organic_carbon_dry_aerosol and
> organic_carbon_as_particulate_organic_carbon_dry_aerosol. In these cases, could
> you not omit the first "organic"? - since carbon is carbon, and whether it is
> organic depends on what it is a constituent of.
In the aerosol community, organic_carbon describes a wild mixture of
unknows organic carbon emissions from plants and industry. It is (as
above for NH4 and SO4) sometimes given as mass of carbon and sometimes
as mass of particulate carbon with a vague conversion factor of about
1.3 to 1.4.
But it should be changed to
particulate_organic_carbon_as_particulate_organic_carbon_dry_aerosol
>
> * How can you have a wet deposition flux of a dry aerosol? What does "dry
> aerosol" mean, I wonder.
Aerosol takes up ambient water depending the relative humidity and its
composition, this is know hygroscopic growth. Dry_aerosol means aerosol
without water.
Wet deposition flux means the aerosol mass transported downwards within
precipitation, i.e. scavenging by rain/snow/graupel etc. Therefore, it
is consistent to have wet deposition of dry aerosol, althought it sound
strange, I agree.
>
> * Like Roy, I don't know what mercury_0 and mercury_2 mean.
>
> * I don't understand aerosol_water_ambient_aerosol.
Aerosol takes up ambient water depending the relative humidity and its
composition, this is known hygroscopic growth. Dry_aerosol means aerosol
without water.... and aerosol_water is the water contained in aerosol.
The suffix _ambient_aerosol is added to be consistent with the suffix
_dry_aerosol elsewhere.
>
> * I can understand non_methane_volatile_organic_compounds but I don't know what
> they are. Are they a well-known group so that this is obvious to an expert?
> Later they appear as NMVOC. I think we should have one or the other, and
> putting it in full seems more consistent with your other names.
I put non_methane_volatile_organic_compounds everywhere.
non_methane_volatile_organic_compounds is a widely used term to describe
a wild mixture of compounds, the composition of which is not entirely
known (similar to particulate_organic_carbon for the aerosols), this is
why they are summarized in this expression. However, it is known what
they are NOT, i.e. methane. I think it is important to include it as
standard name.
>
> * CO should appear as carbon_monoxide.
d'accord!
>
> Use of dimensions:
>
> * Some of the names have numerical values in them. This is not in keeping with
> usual practice in standard names. For instance, we do not have standard names
> for surface air temperature at 1.5 m or 2 m height. Instead, we use coordinates
> for independent variables. In names like these:
> mole_fraction_of_CO_with_lifetime_of_25_days_in_air
> pm10_aerosol_ambient_optical_depth_at_550_nm
> mass_fraction_of_pm10_aerosol_at_50_percent_relative_humidity_in_air
> I think the lifetime, particle radius, wavelength and relative humidity should
> be coordinates (probably scalar coordinate variables), rather than being in the
> standard name. This requires standard names to be defined for the independent
> variables you need.
Let me explain:
> mole_fraction_of_CO_with_lifetime_of_25_days_in_air
is an artificial tracer for a specific sensitivity study, so maybe it
needs a coordinate variable, similar to those emitted in specific regions
> pm10_aerosol_ambient_optical_depth_at_550_nm
550 nm is one of the few wavelenghts for which the optical depth is
measured. The use a coordinate variable is feasable.
> mass_fraction_of_pm10_aerosol_at_50_percent_relative_humidity_in_air
The use a coordinate variable for the rel. hum is feasable, but to be
consistent, the use of _dry_aerosol should than be substituted by also
using this coordinated variable with rel.hum.=0. But what if
rel.hum=ambient humidity, i.e. not a numerical value? Is it possible to
have both _dry and _ambient and for all other cases a coordinate variable?
>
> * In a similar way, you have phrases from_North_America, from_South_Asia and so
> on. I know this is similar to the construction from_stratosphere which we
> discussed in your guidelines, but I don't think we ought to include geo-
> graphical areas in standard names. We have already defined a standard_name of
> region for use as a geographical "coordinate". Your use is not quite the same
> because you want to identify where something comes from, rather than its
> present location, so perhaps we should introduce a new name of source_region
> for instance, with the same possible values as region; these come from a list
> which can be extended as required.
The this is in principal a good idea. The source_regions have specific
spatial extensions, which might be different for different experiments.
variables:
float VMR_CO(time,lat,lon,lbl);
VMR_CO:unit="1";
VMR_CO:coordinates="source_region";
VMR_CO:standard_name="mole_fraction_of_CO_in_air";
double time(time) ;
time:long_name = "time" ;
time:units = "days since 1990-1-1 0:0:0" ;
float lat(lat) ;
lat:long_name = "latitude" ;
lat:units = "degrees_north" ;
float lon(lon) ;
lon:standard_name = "longitude" ;
lon:long_name = "longitude" ;
lon:units = "degrees_east"
char region_name(lbl,strlen) ;
region_name:standard_name="source_region"
region_name:bounds = "region_bnds" ;
float region_bnds(lbl,latmin,latmax,lonmin,lonmax) ;
or
float region_bnds(lbl,regbnds) ; with regbnds=4
or something like that?? (I do not understand, why 'region' has the
dimension 'strlen' in your examples, it seems redundant to me, or is it
necessary for netcdf?
However, in the context of HTAP it would be better to specify a
coordinate variable for
mole_fraction_of_CO_in_air indicating the different experiments with CO
tagged per source region, but also including the artificial
mole_fraction_of_CO_with_lifetime_of_25_days_in_air
Is this possible?
>
> Other points:
>
> * grid_cell_area and _height. These are metrics for the grid, rather than
> quantities which need standard names. Grid cell area should be specified by a
> cell_measures variable of area (CF 7.2). Grid cell height can be deduced as the
> difference between the lower and upper boundary in the vertical coordinate. If
> it has to be stored separately we could add a cell_measures for it.
>
Yes, I know that the cell_measures exist, but it is convenient to have
the grid information stored in variables. It would be nice if these
names could be added.
> * atmosphere_mass_content_of_air. I think we agreed this would be named in the
> more obvious way atmosphere_mass_per_unit_area, since it seems strange to
> give something a "content" name for its entire content!
it should then be atmosphere_mass_of_air_per_unit_area to exclude
preciptation etc. or other particles (or planes?)
>
> * "of" is missing in surface_emission_mass_flux_ammonia.
d'accord
>
> Best wishes
>
> Jonathan
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>
--
Christiane Textor
GMES France Atmosph?re - GEMS France
Service d'A?ronomie INSU CNRS, Tour 46, RDC # 2
Universit? Pierre et Marie Curie, Boite 102
4 place Jussieu
75252 Paris C?dex 05
France
Tel: ++33 1.44.27.21.82
Fax: ++33 1.44.27.21.81
Email: christiane.textor at aero.jussieu.fr
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Received on Wed Sep 27 2006 - 00:53:45 BST
