Hi Damien,
thanks for taking the initiative on behalf of IGAS!
I was looking through your list of proposed standard names and compared it to
those I had proposed earlier as an initiative of the WMO GAW Scientific Advisory
Group for Aerosol. Due to the process of iterating this list of names between 3
different bodies, the GAW SAG list hasn't been finally accepted here yet, but we
are fairly close, so we should make sure the 2 lists are aligned. I had
previously proposed the following names:
1. number_size_distribution_of_dried_aerosol_particles_at_stp_in_air
The particle number size distribution is the number concentration of aerosol
particles per decadal logarithmic size interval as a function of particle
diameter. "Aerosol" means the suspended liquid or solid particles in air
(except cloud droplets). "Dried_aerosol" means that the aerosol sample has
been dried from the ambient state, but that the dry state (RH < 40%) hasn't
necessarily been reached. To specify the relative humidity at which the
property applies, provide scalar coordinate variable with the standard name
of "relative_humidity". "at_stp" refers to a volume at standard conditions
of temperature (273.15 K) and pressure (1013.25 hPa). A coordinate variable
of ?electrical_mobility_particle_diameter? needs to be specified to indicate
that the property applies at specific particle sizes.
2. number_size_distribution_of_cloud_condensation_nuclei_at_stp_in_air
The cloud condensation nuclei number size distribution is the number
concentration of aerosol particles per decadal logarithmic size interval as
a function of particle diameter that act as condensation nuclei for
liquid-phase clouds. "Aerosol" means the suspended liquid or solid particles
in air (except cloud droplets). "Dried_aerosol" means that the aerosol
sample has been dried from the ambient state before sizing, but that the dry
state (RH < 40%) hasn't necessarily been reached. To specify the relative
humidity at which the sample was sized, provide scalar coordinate variable
with the standard name of "sizing_relative_humidity". "at_stp" refers to a
volume at standard conditions of temperature (273.15 K) and pressure
(1013.25 hPa). Coordinate variables of
?electrical_mobility_particle_diameter? and ?relative_humidity? need to be
specified to indicate that the property refers to specific particle sizes
and supersaturations with respect to liquid water.
Those names don't align with the ones you proposed in a few aspects. In the
discussion of these names, we discovered that we need to be textbook strict and
unambiguous when using the term "aerosol" (system of particles and carrier gas).
That's why the iterated names use "aerosol_particles" to be precise and avoid
confusion. Also, from the definition of your names, I have difficulty
understanding what precisely you mean with "size_resolved_number_concentration".
Is this a number size distribution, or a set of number concentrations of
particles in defined size intervals? Size distributions are commonly normalised
by the decadal logarithmic size interval applicable for each size bin. That way,
it is possible to state the size distribution with only one coordinate variable
in particle diameter. To state the particle number concentration as such for
defined particle diameter bins is rather unusual. You would need 2 coordinate
variables (upper and lower particle diameter limiting each size bin) to be
precise. In the discussion of the GAW SAG names, we also touched upon the issue
how the particle diameter is determined. The result usually depends on the
measurement method used. To be precise, you would need a coordinate variable
such as "optical_particle_diameter".
Best regards,
Markus
Am 18.09.2014 01:08, schrieb John Graybeal:
> Hi J?rg,
>
> Thanks for clarifying the units. I agree with the semantic concern you raise
> about the names. I couldn't make the description fit the name terminology
> after several attempts, but I am a novice in that domain.
>
> Regarding " the tradition in the CF community to combine variable and matrix
> or platform", could you describe what you mean by this? I don't know which
> terms are combining matrix or platform -- platform for example only (?) comes
> into play when the measurement is of a platform and its characteristics, and
> I'm guessing you'll agree that this needs to be kept distinct from
> measurements of ambient conditions in the environment.
>
> John
>
> On Sep 17, 2014, at 09:00, Joerg.Klausen at meteoswiss.ch
> <mailto:Joerg.Klausen at meteoswiss.ch> wrote:
>
>> Hi Damien and colleagues
>> The units for the number concentrations are okay IMHO, it?s particles per
>> volume, so 1/m^3 or m-3 should be right. I agree with John?s comment on
>> vertical velocity, to specify a direction makes sense. I have a problem with
>> the ?size_resolved_number_concentration_? terminology, which I have always
>> had but comment on here for the first time: I find it not very telling and
>> semantically wrong. In my understanding, the term should be more sth like
>> ?size_spectrum_of_number_concentration_?.
>> A more general concern I have (with the plethora of
>> variable/matrix/platform/size-cutoffs in GAW in mind) is the tradition in the
>> CF community to combine variable and matrix or platform. From a data
>> management point of view, combining various dimensions is what one rather
>> tries to avoid as the number of possible permutations makes code lists grow
>> tremendously long. A better approach would be to develop codelists for the
>> individual dimensions and then draw from those. I am not sure a consensus on
>> this view will be found, though.
>> Kind regards
>> J?rg
>> _________________________________
>> *Dr. J?rg Klausen*
>> Measurements and Data Department
>> Federal Department of Home Affairs FDHA
>> *Federal Office of Meteorology and Climatology MeteoSwiss*
>> Operation Center 1 | P.O. Box 257 | CH-8058 Z?rich-Flughafen
>> Phone: +41 58 460 92 23 | Fax: +41 58 460 90 01
>> joerg.klausen at meteoswiss.ch <mailto:joerg.klausen at meteoswiss.ch>| Mobile: +41
>> 79 702 94 67
>> All about weather and climate at
>> www.meteoswiss.ch <http://www.meteoschweiz.admin.ch/web/en.html>andMeteoSwiss
>> App <http://www.meteoswiss.admin.ch/web/en/services/telecommunication/app.html>
>>
>> All about GAW observations at
>> www.meteoswiss.ch/gawsis <http://www.meteoswiss.ch/gawsis>
>>
>> *From:*John Graybeal [mailto:john.graybeal at marinexplore.com]
>> *Sent:*Dienstag, 16. September 2014 18:22
>> *To:*Damien Boulanger
>> *Cc:*CF Metadata List; Armin Rauthe-Sch?ch; Martin Schultz; Klausen J?rg
>> *Subject:*Re: [CF-metadata] IAGOS-CARIBIC parameters
>> Hi Damien,
>> You've started the process nicely. What happens next is that various people
>> on the list comment on your names and definitions, and the process continues
>> until consensus is reached. Don't feel obligated to respond to every post,
>> just join in as you find it appropriate. (If your colleagues want to follow
>> all the posts, they'll want to be subscribed to the list.)
>> I'll kick it off with a few comments on the more 'generic' terms.
>> vertical_speed probably needs to be more specific, since most terms capture
>> both the aubstance or object (in this case the airplane) and the process.
>> Following the other platform terms, I suggest naming this
>> platform_vertical_speed. (it isn't clear whether this is a directional speed,
>> e.g., negative numbers are down? If so then platform_upward_vertical_speed
>> would be better.) The definition should reflect these changes, and will
>> include the stock phrase "Speed is the magnitude of velocity." Also, the
>> canonical units for this item need to be distance/time, so m s-1.
>> Your description of total_air_temperature sounds like the stagnation is the
>> key point of this measurement. I would propose stagnant_air_temperature as a
>> starting point. And, it seems this measurement may be as much about the
>> platform as about the air itself (if the stagnation is caused by the
>> platform); perhaps this should be included in the name, to distinguish from
>> an environmentally stagnant patch of air. That name could be
>> stagnant_air_temperature_due_to_platform, for example.
>> One other comment about units, the units for the first 3 terms may be off.
>> For a volume you'd want m3 (cubed m) not m-3 (1 over cubed m), but the
>> description doesn't seem like a volume. Other people with more expertise on
>> this topic can chime in here.
>> John
>> ------------------------------------
>> *John Graybeal*
>> Marine Data Manager
>>
>> M +1 408 675-5445
>>
>> Marinexplore
>>
>> On Sep 16, 2014, at 00:20, Damien Boulanger <damien.boulanger at obs-mip.fr
>> <mailto:damien.boulanger at obs-mip.fr>> wrote:
>>
>>
>> Dear all,
>>
>> within the frame of the IGAS project (IAGOS for Copernicus Atmospheric
>> Service,http://www.igas-project.org
>> <http://www.igas-project.org/index.php/ProjectInfo/ProjectInformation>) we
>> would like to propose 5 new CF standard names:
>>
>> *standard_name*
>>
>> *units*
>>
>> *definition*
>> size_resolved_number_concentration_of_dry_aerosol_in_air
>>
>> m-3
>>
>> Size resolved denotes the capability of an instrument to measure aerosol
>> properties in different size ranges. The size range of particles is typically
>> given as a range of particle diameters in nm assuming spherical shape and
>> must be provided in a comment attribute. Number concentration means the
>> number of particles or other specified objects per unit volume. "Aerosol"
>> means the suspended liquid or solid particles in air (except cloud droplets).
>> "Dry aerosol" means aerosol without water.
>> particle_surface_area_concentration_of_dry_aerosol_in_air
>>
>> m-3
>>
>> Surface area per volume derived from the size resolved particle number
>> concentration. "Aerosol" means the suspended liquid or solid particles in air
>> (except cloud droplets). "Dry aerosol" means aerosol without water.
>> size_resolved_number_concentration_of_cloud_liquid_water_particles_in_air
>>
>> m-3
>>
>> Size resolved denotes the capability of an instrument to measure aerosol
>> properties in different size ranges. The size range of particles is typically
>> given as a range of particle diameters in nm assuming spherical shape and
>> must be provided in a comment attribute. Number concentration means the
>> number of particles or other specified objects per unit volume. Cloud
>> droplets are spherical and typically a few micrometers to a few tens of
>> micrometers in diameter. An upper limit of 0.2 mm diameter is sometimes used
>> to distinguish between cloud droplets and drizzle drops, but in active
>> cumulus clouds strong updrafts can maintain much larger cloud droplets.
>> vertical_speed
>>
>> 1
>>
>> Rate of change of aircraft altitude.
>> total_air_temperature
>>
>> K
>>
>> Total air temperature or stagnation temperature is the temperature at a
>> stagnation point in a fluid flow. Measured by a temperature probe mounted on
>> the surface of the aircraft.
>>
>>
>> I'm not really sure what is the standard procedure. Let me know if you need
>> any more information.
>>
>> Best regards,
>> Damien Boulanger and the IGAS team
>>
>>
>> --
>> Damien Boulanger
>> CNRS - UMS831 OMP - SEDOO
>> Observatoire Midi-Pyr?n?es
>> 14 Avenue Edouard Belin 31400 Toulouse - France
>> Phone: (+33) 05-61-33-27-71
>> Email: damien.boulanger at obs-mip.fr <mailto:damien.boulanger at obs-mip.fr>
>> _______________________________________________
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>> CF-metadata at cgd.ucar.edu <mailto:CF-metadata at cgd.ucar.edu>
>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>
>
>
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--
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: Markus.Fiebig at nilu.no
skype: markus.fiebig
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