Dear Alison,

     great overview! Thanks very much for this. I am happy with all of your 
suggestions, so you can count my vote if needed.

    Concerning the "resistance" terminology: This refers to a resistance model 
approach for which a paper by Wesely, 1989 (Atmos. Env., 23/6) is widely 
referred to. This paper talks about "surface resistances" and explicitly 
mentions "aerodynamic resistance", "quasilaminar sublayer resistance", and 
"bulk surface resistance", the latter being composed of various terms, among 
them a term for "stomatal resistance". Explicit reference is made to Ohm's law 
as analogy, and this concept is widely known in the community. I would hence 
argue in favour of keeping the word resistance in these terms.

With best regards,

Martin


Message: 2
Date: Fri, 21 Nov 2014 12:18:34 +0000
From: <alison.pamm...@stfc.ac.uk>
To: <cf-metadata@cgd.ucar.edu>
Cc: frank.dente...@jrc.ec.europa.eu, michael.sch...@lsce.ipsl.fr
Subject: Re: [CF-metadata] HTAP2 last revisions
Message-ID:
        <014539ac4976be4490a360410a8c2017792a8...@exchmbx03.fed.cclrc.ac.uk>
Content-Type: text/plain; charset="us-ascii"

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.

[...]

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 form
 ulation? 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: alison.pamm...@stfc.ac.uk
STFC Rutherford Appleton Laboratory
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.



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