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 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
> _________________________________
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>
> 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> wrote:
>
>
> Dear all,
>
> within the frame of the IGAS project (IAGOS for Copernicus Atmospheric Service, http://www.igas-project.org) 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
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