Dear Seth,
>
> I still have not found any datasets using the existing name
> atmosphere_specific_convective_available_potential_energy, so I suspect
> that it doesn't actually matter which way it is aliased.
>
Thanks for researching this. Looking back through our numbered versions of the standard name table I see that the original name has been around
since version 1 which means that it existed before the creation of the current CF website and pre-dates my own involvement with CF. It is therefore quite surprising that no one seems to have used it! Perhaps it was part of a list of names originating from when the CF standard was under development.
>
> I stated the argument for aliasing it to (7) rather than (8) in the
> previous argument, but I don't feel strongly about it, and would be
> happy with either. If we haven't had any discussion from the list in,
> say, two weeks, could we consider it resolved?
Just to remind everyone, you are suggesting that we make atmosphere_specific_convective_available_potential_energy an alias of atmosphere_convective_available_potential_energy (J kg-1). This is defined as:
'Convective(ly) available potential energy (often abbreviated CAPE) is a stability measure calculated by integrating the positive temperature difference between the surrounding atmosphere and a parcel of air lifted adiabatically from a given starting height to its equilibrium level. A coordinate variable of original_air_pressure_of_lifted_parcel should be specified to indicate the starting height of the lifted parcel. CAPE exists under conditions of potential instability, and measures the potential energy per unit mass that would be released by the unstable parcel if it were able to convect upwards to equilibrium.'
The alternative would be to make the existing name an alias of atmosphere_convective_available_potential_energy_wrt_surface (J kg-1) and defined as:
'Convective(ly) available potential energy (often abbreviated CAPE) is a stability measure calculated by integrating the positive temperature difference between the surrounding atmosphere and a parcel of air lifted adiabatically from the surface to its equilibrium level. CAPE exists under conditions of potential instability, and measures the potential energy per unit mass that would be released by the unstable parcel if it were able to convect upwards to equilibrium.'
I agree that of the two new proposals, the first does sound more generic and therefore closer to the existing name. Indeed there would be nothing to stop someone from providing a value for original_air_pressure_of_lifted_parcel that was actually the surface air pressure so atmosphere_convective_available_potential_energy could be used to describe any CAPE variable.
I agree with your suggestion of allowing two weeks for comments. If no further comments are received by that time then, yes, the issue is resolved.
Best wishes,
Alison
------
Alison Pamment Tel: +44 1235 778065
NCAS/British Atmospheric Data Centre Email: alison.pamment at stfc.ac.uk
STFC Rutherford Appleton Laboratory
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.
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Received on Tue Nov 12 2013 - 07:44:24 GMT
