Hi Philip,
I agree with your proposals.
I think it's a good idea to adopt an existing phrase for std_names
that fits our needs - thanks for letting me know this.
Best wishes,
Tomoo
----- Original Message -----
From: "Cameron-smith, Philip" <cameronsmith1 at llnl.gov>
To: "Tomoo Ogura" <ogura at nies.go.jp>; "Bert Jagers" <bert.jagers at deltares.nl>; "Jonathan Gregory"
<j.m.gregory at reading.ac.uk>
Cc: "Jennifer Kay" <jenkay at ucar.edu>; "Yoko Tsushima" <yoko.tsushima at metoffice.gov.uk>;
<cf-metadata at cgd.ucar.edu>
Sent: Friday, March 11, 2011 11:15 AM
Subject: RE: [CF-metadata] Proposal for new standard names - use of"sedimentation"
Thanks, Bert.
I am embarrassed to say that I didn't notice/remember/discover that CF already has the term/phrase
we need until your email. It is:
gravitational_settling
This is used in 6 std_names, and has the meaning that we want, although the distinction/overlap with
precipitation was never discussed, presumably because these std_names were connected to movement of
aerosols.
An example of one of the existing std_names is:
tendency_of_atmosphere_mass_content_of_black_carbon_dry_aerosol_due_to_gravitational_settling
Hence, I propose that we replace 'sedimentation' with 'gravitational settling' in your std_names for
cloud drops.
I further propose that we still add text to the descriptions that clearly distinguishes
'gravitational_settling' from 'precipitation' along the lines you previously proposed.
As a footnote for the grammar discussion in another thread: I would have been more likely to
discover the 'gravitational_settling' term if CF was using a grammar-vocabulary system.
Best wishes,
Philip
-----------------------------------------------------------------------
Dr Philip Cameron-Smith, pjc at llnl.gov, Lawrence Livermore National Lab.
-----------------------------------------------------------------------
> -----Original Message-----
> From: cf-metadata-bounces at cgd.ucar.edu [mailto:cf-metadata-
> bounces at cgd.ucar.edu] On Behalf Of Tomoo Ogura
> Sent: Wednesday, March 09, 2011 1:57 AM
> To: Bert Jagers; Cameron-smith, Philip; Jonathan Gregory
> Cc: Jennifer Kay; Yoko Tsushima; cf-metadata at cgd.ucar.edu
> Subject: Re: [CF-metadata] Proposal for new standard names - use of
> "sedimentation"
>
> Dear Bert,
>
> Many thanks for your comments and suggestions.
>
> In the proposed new standard names, the word "sedimentation"
> was meant to represent the gravitational settling of cloud
> liquid water droplets.
> I agree that the above usage of "sedimentation" does not
> match a transition from one medium to another. Therefore,
> we may need to look for another word to avoid confusion.
>
> As an alternative, the suggested word "settling" sounds
> good to me. In this case, the proposed standard names
> will be as follows;
>
> (a) tendency_of_mass_fraction_of_stratiform_cloud_liquid_water
> _in_air_due_to_settling_of_cloud_liquid_water,
> and
> (b) tendency_of_mass_fraction_of_stratiform_cloud_condensed_water
> _in_air_due_to_settling_of_cloud_liquid_water.
>
> Best wishes,
>
> Tomoo
>
> ----- Original Message -----
> From: "Bert Jagers" <bert.jagers at deltares.nl>
> To: "Tomoo Ogura" <ogura at nies.go.jp>; "Cameron-smith, Philip"
> <cameronsmith1 at llnl.gov>; "Jonathan
> Gregory" <j.m.gregory at reading.ac.uk>
> Cc: "Jennifer Kay" <jenkay at ucar.edu>; "Yoko Tsushima"
> <yoko.tsushima at metoffice.gov.uk>;
> <cf-metadata at cgd.ucar.edu>
> Sent: Wednesday, March 09, 2011 9:22 AM
> Subject: Re: [CF-metadata] Proposal for new standard names - use of
> "sedimentation"
>
>
> > Dear all,
> >
> > Unfortunately I have had far too little time to contribute to the CF
> mailing list over the past
> > year, but I try to scan the titles of mails coming in and now and
> then I read a post. I didn't
> > intend to read this thread until my eye accidentally caught the word
> "sedimentation" in body text.
> > As someone involved in sediment transport in rivers, estuaries,
> coastal areas and to a much lesser
> > oceans, I do have a strong association with the word "sedimentation".
> As a result I have some
> > concerns with the appropriateness of the chosen word.
> >
> > If I interpret the most recent discussion correctly, the proposal is
> to use the word
> > "sedimentation" for the slow downward motion of liquid water in the
> atmosphere; not being an
> > atmospheric scientist I'm trying to grasp what that actually means.
> The discussion distinguishes
> > it from definitions including terms like "accretion" and
> "autoconversion" which based on the
> > description in the standard name table both seem to be related the
> growth of droplets and ice
> > crystals; flocculation is the associated process in cohesive sediment
> modeling. Other processes
> > that thus would be included in your new definition of "sedimentation"
> include: vertical advection
> > due to general air velocity, turbulent mixing, relative gravitational
> settling of the
> > droplets/crystals, ... more?
> >
> > In sediment transport, the words "sedimentation" and "deposition" are
> generally used to mean the
> > reverse of "erosion". The former two mean that sediment falls from
> suspension onto the bed ("ocean
> > floor"), whereas "erosion" means the uptake of sediment from the bed
> by the flow. Now, let us see
> > how the word "sedimentation" was used before in CF names. The term
> "sedimentation" has so far been
> > used in three standard names related to the ocean_mole_content of
> three chemical substances. These
> > names are associated with 2D quantities (quantities per unit area)
> which matches my interpretation
> > of the word (and the common use of this word): the amount of the
> substances considered (carbon,
> > elemental nitrogen, and iron) in the ocean column is reduced due to
> the fact that organic
> > suspended sediment settles onto the ocean floor. Basically it
> includes a transition from one
> > medium (in the water column) to another medium (in/on the ocean
> floor). The newly proposed use of
> > the term "sedimentation" does not match such a transition.
> >
> > Thinking along these lines I looked at the word "deposition" which is
> used more frequently in
> > standard names. However, mostly it is used in combination with "dry",
> "wet" or "turbulent" and
> > seem to be associated with the transition of substances from medium
> atmosphere to the medium ocean
> > (or land): a 2D flux field of 2D variable "atmosphere mass content"
> in line with the use of the
> > word "sedimentation" described above. The word "deposition" without
> "dry" or "wet" is less
> > uniquely tied to a specific process. It has been used as the reverse
> of "sublimation" in
> >
> tendency_of_mass_fraction_of_stratiform_cloud_ice_in_air_due_to_deposit
> ion_and_sublimation, as the
> > sum of "dry deposition" and "wet deposition" (= "turbulent
> deposition" + "gravitational
> > settling"), and in a non-specified manner in
> >
> tendency_of_ocean_mole_content_of_iron_due_to_deposition_and_runoff_and
> _sediment_dissolution.
> >
> > In ocean modeling I would tend to use the word "settling" for the
> downward motion of sediment
> > relative to the water without necessarily hitting the ocean floor,
> but also the word "settling"
> > has so far only been used in combination with 2D variables of type
> "atmosphere mass content" and
> > deposition.
> >
> > Best regards,
> >
> > Bert
> > ------
> >
>
>
> _______________________________________________
> CF-metadata mailing list
> CF-metadata at cgd.ucar.edu
> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Received on Thu Mar 10 2011 - 22:29:51 GMT
