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 <[email protected]> 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 >_______________________________________________ >CF-metadata mailing list >[email protected] >http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
