Dear Martin
> > 1) proposed standard_name: air_mass units: kg
>
Actually I am concerned about this:
> I don't think that the common
> meteorological definition of air mass would be in conflict with this
I do think it could be confusing, and that mass_of_air would be better to
avoid this confusion.
> It would be great if one could perform a
> fulltext search on the archive.
When I want to do this, I view the "downloadable version" in the browser e.g.
http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2009.txt
and search it with text-search (find in this page).
> > 4) proposed standard_name: upper_tropopause_level_index units:
> index
>
> model_level_number_at_tropopause is OK. The philosophical distinction
> between the "upper" and "lower" tropopause could be done in the
> cell_methods field if needed?
I don't think so, as that is more intended for statistical variation within
a cell. What is the distinction? If there are two kinds of tropopause, it
would be best to give then distinct "surface" names for the at_SURFACE phrase.
> tendency_of_precipitation_mass_due_to_formation
> and
> tendency_of_precipitation_mass_due_to_evaporation
I would suggest that "condensation" might be a more obvious opposite to
"evaporation". I wonder why you want these to be kg s-1 and not kg m-2 s-1?
Most existing names are per m2 e.g. tendency_of_atmosphere_mass_per_unit_area.
If also it is going to be a function of a vertical coordinate as well, maybe
kg m-3 would be preferable i.e. a mass_concentration. Then it would be
intensive in all special dimensions.
I think we should try to avoid a potential confusion about whether
precipitation specifically means something arriving at the surface (as it
does in almost all existing names) or something in the body of the atmosphere.
We could say tendency_of_atmosphere_mass_of_precipitation_due_to_X to get
round this. If they were kg m-2 s-1 they would be
tendency_of_atmosphere_mass_content_of_precipitation_due_to_X
which is a construction we have used for many chemical species.
tendency is a signed quantity; it's just a derivative wrt time. Hence it
is positive for condensation and negative for evaporation. I agree that it
would be helpful to clarify that in the guidelines.
I expect that Alison will summarise the status of the chemical names. My
impression of the debate was that the preference was for including all names
explicitly for the moment in the table, to ensure they are all sensible, but
I'll wait for Alison's conclusion. Yes, there are many names to be agreed
for AR5 runs.
Best wishes
Jonathan
Received on Tue Jan 20 2009 - 02:10:56 GMT
