Hi Jonathan (G),
I had thought we needed the finish level for CAPE and CIN, but after
consulting with a colleague, I realize we actually don't need it.
For the CAPE & CIN calculations, you integrate until the parcel hits
equilibrium. I am assured that it will suffice just to mention that in the
definition of the standard_name, and that there's no need to record
the actual location of equilibrium level as an ancillary coordinate.
(It's pretty much always the tropopause, and it's almost never
interesting.)
So I say let's abandon the air_pressure_of_lifted_parcel_at_finish
standard name entirely, and just add a standard_name for the
pressure at the start of lifting.
I'm equally happy with _at_start, _at_origin, or _at_source for that.
If we're worried about being as clear as possible, should we consider
air_pressure_of_lifted_parcel_at_start_of_lifting? It's clunky, but
unlikely to be misinterpreted...
I'll update my proposed names in a separate messages.
Cheers,
--Seth
On Tue, 4 Jun 2013 10:28:50 +0100
Jonathan Gregory <j.m.gregory at reading.ac.uk> wrote:
>Dear all
>
>I chose a new subject because these threads about lifted_index, total_totals_
>index and Seth's new standard names for CIN etc. are closely related.
>
>I agree with the suggestion from Philip to include _from_the_surface on names
>referring to surface parcels (it was previously clarified that really means
>from the surface, not "surface air" i.e. screen height), and omit it when the
>parcel comes from a different level that is identified by a numeric
>coordinate.
>That is consistent with the general pattern that special physical surfaces
>(such as the surface i.e. bottom of atmos) appear by name in standard_names
>when relevant, whereas levels specified by coordinates do not.
>
>Excuse my making a late suggestion on another matter. I think "start" and
>"finish" are OK but they make it sound like a real trajectory, whereas these
>are just calculations from the state of the atmos. I would therefore like to
>suggest "source" (for "start"), which has the same sense of "where the parcel
>came from" that "origin" has, but doesn't have the potential confusion. E.g.
>air_pressure_of_lifted_parcel_at_source. What do you think?
>
>As for "finish", which names require this? I wonder about using "ambient" for
>"finish", in cases where the idea is to compare the parcel with the
>environment
>at the end of its notional journey. Again, what do you think?
>
>Going back to Seth's proposal, I wonder if
>atmosphere_specific_convective_inhibition
>atmosphere_specific_convective_available_potential_energy
>are really best regarded as a trajectory. They are integral quantities. In
>those two cases, I suggest it would be fairly natural to give them bounds in
>a vertical coordinate to indicate the limits of integration.
>
>Best wishes
>
>Jonathan
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Received on Tue Jun 04 2013 - 15:48:16 BST
