Another option is to use the term sink instead of ambient, which would be more
parallel to source and attribute less semantic knowledge about the destination
location. Then air_pressure_of_lifted_parcel_at_sink would be a good analog.
('Destination' is another option too.)
On Jun 4, 2013, at 14:02, Jonathan Wrotny <[email protected]> wrote:
> Dear Jonathan Gregory,
>
> Thanks for creating the new thread....
>
> I see your point on how "start" and "finish" could imply a trajectory and
> that we should avoid this. I like the word "source" instead of "start."
> "Ambient" doesn't imply any height, in and of itself. But, since it is used
> in the standard name and definition, hopefully it is clear to others that it
> refers to the final pressure level in the "notional journey" of the lifted
> parcel, like you say. I'm not sure of the best names for the coordinate
> variables, but here is my crack at them. Perhaps Seth can chime in and make
> any suggestions he has - hopefully this doesn't "throw off" his proposed
> definitions too much.
>
> Associated coordinate variables:
>
> Standard_names:
>
> air_pressure_of_lifted_parcel_at_source
> ambient_air_pressure_of_lifted_parcel
>
> Definitions:
>
> Various stability and convective potential indices are calculated by
> "lifting" a parcel of air: moving it dry adiabatically from a starting height
> (often the surface) to the Lifting Condensation Level, and then wet
> adiabatically from there to an ending height (often the top of the
> data/model/atmosphere). air_pressure_of_lifted_parcel_at_source and
> ambient_air_pressure_of_lifted_parcel are the pressure heights at the start
> and end of lifting, respectively.
>
> Canonical units: Pa
>
> The only one of the four stability indices that I have proposed which uses
> these coordinate variables is the lifted index. I will wait to send an
> updated definition for the lifted index once we have resolved the coordinate
> variables question.
>
> Sincerely,
>
> Jonathan
>
> On 6/4/2013 5:28 AM, Jonathan Gregory 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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---------------
John Graybeal
Marine Metadata Interoperability Project: http://marinemetadata.org
[email protected]
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