[CF-metadata] standard name proposal for CCMVal

From: Pamment, JA <J.A.Pamment>
Date: Thu, 6 Mar 2008 09:48:22 -0000

Dear Jonathan,

Thank you for your comments.

> I noticed two small things
> which I should have commented on before, but didn't notice then
> unfortunately.
> It may be too late now, but anyway:
>
> > mole_fraction_of_passive_ozone_in_air; 1; This is a tracer quantity
> The definition at least should make clear what "passive" means in this
> context,
> or (even better) would it be possible to use something more explicit?
> In an
> ocean context, we might have a "passive salinity" tracer, for
instance,
> which
> would be one that did not affect density, but I don't suppose that
> would be
> the same meaning of "passive" as in atmospheric chemistry. You can
> imagine
> having a "passive" chemical tracer in the ocean, for which it could be
> ambiguous what "passive" meant. So I fear this is potentially
> confusing.
>
I hadn't appreciated that there could be more than one kind of
passivity! I think that we could clarify this by a small modification
to the name:
mole_fraction_of_passive_ozone_in_air ->
mole_fraction_of_chemically_passive_ozone_in_air

> > dynamic_tropopause_potential_temperature; K
> I would suggest the order potential_temperature_at_dynamic_tropopause,
> for
> consistency with the treatment of other multi-word "level" names.
>
I should have spotted this, sorry.
potential_temperature_at_dynamic_tropopause is better.

Martin do you have any objection to these slightly modified names?

> Regarding
> > mean_age_of_stratospheric_air
> my understanding from the earlier discussion (subject to correction by
> experts)
> is that in a Lagrangian model it would be a mean over the parcels in a
> gridbox,
> but in an Eulerian model it is the concentration of an age tracer, and
> hence
> in practice a volume-mean over the gridbox, just like most intensive
> quantities
> (such as temperature). In either case the "mean" could be indicated by
> cell_
> methods.
>
Ah, okay. If that is the case then we could accept the name as
"age_of_stratospheric_air" and use cell_methods as you suggest. In the
Lagrangian case would you need to have an axis which indexed the
different parcels? Please forgive my ignorance about this - I have no
experience of using Lagrangian models.

Best wishes,
Alison

------
Alison Pamment Tel: +44 1235 778065
NCAS/British Atmospheric Data Centre Fax: +44 1235 446314
Rutherford Appleton Laboratory Email: J.A.Pamment at rl.ac.uk
Chilton, Didcot, OX11 0QX, U.K.
Received on Thu Mar 06 2008 - 02:48:22 GMT