Dear Seth
Thanks for the updated list of names. This all looks logical to me.
I now wonder whether, in the names, wrt_surface would convey the meaning more
obviously than from_the_surface. It's not obvious until you read the definition
why it's "from", I think. I feel that "wrt" would more immediately indicate
As you note
> atmosphere_specific_convective_available_potential_energy
> [update to existing standard_name]
is an existing standard name. The existing definition is not clear, but I
suspect it might be interpreted as the whole-atmos version i.e. wrt surface.
What do you think? In that case, this update would be a redefinition, not a
clarification, and we should avoid redefining existing names. If that is the
case, it could be avoided by adding another phrase to the name for the version
when the parcel does not come from the surface. Then the existing name could
be made an alias of the new "wrt surface" name. What do you think?
Best wishes and thanks
Jonathan
----- Forwarded message from Seth McGinnis <mcginnis at ucar.edu> -----
> From: Seth McGinnis <mcginnis at ucar.edu>
> To: cf-metadata at cgd.ucar.edu
> X-Mailer: CommuniGate Pro WebUser v6.0.1
> Date: Fri, 14 Jun 2013 16:44:36 -0600
> Subject: Re: [CF-metadata] new standard names for CIN, LFC,LCL; update to
> CAPE
>
> Hi all,
>
> Here are the updated proposals for new standard names for CIN, LFC, and LCL;
> an update to the standard name for CAPE; and the two standard names for the
> starting and ending heights of lifted parcels.
>
> Following the suggestion that came up in our discussion, these come in pairs:
> the basic standard name for quantities based on parcels lifted from some
> starting height (which should be specified as a coordinate variable), and a
> name ending in _from_the_surface for parcel starting at the surface.
>
> Cheers,
>
> --Seth
>
>
> #####
>
> original_air_pressure_of_lifted_parcel
>
> 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 a final height (often the top of the
> troposphere). original_air_pressure_of_lifted_parcel is the pressure
> height at the start of lifting.
>
> canonical units: Pa
>
>
> #####
>
> final_air_pressure_of_lifted_parcel
>
> 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
> troposphere). final_air_pressure_of_lifted_parcel is the pressure
> height at the end of lifting.
>
> canonical units: Pa
>
>
> #####
>
> atmosphere_specific_convective_inhibition
>
> "Specific" means per unit mass. Convective inhibition is the amount of
> energy required to overcome the negatively buoyant energy exerted by
> the environment on a parcel of air. Convective inhibition is often
> abbreviated as "CIN" or "CINH". It is calculated by integrating the
> negative 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.
>
> canonical units: J kg-1
>
>
> #####
>
> atmosphere_specific_convective_inhibition_from_the_surface
>
> Convective inhibition is the amount of energy required to overcome the
> negatively buoyant energy exerted by the environment on a parcel of
> air. Convective inhibition is often abbreviated as "CIN" or "CINH".
> It is calculated by integrating the negative temperature difference
> between the surrounding atmosphere and a parcel of air lifted
> adiabatically from the surface to its equilibrium level. "Specific"
> means per unit mass.
>
> canonical units: J kg-1
>
>
> #####
>
> atmosphere_lifting_condensation_level
>
> The lifting condensation level is the height at which the relative
> humidity of an air parcel cooled by dry adiabatic lifting would reach
> 100%. A coordinate variable of original_air_pressure_of_lifted_parcel
> should be specified to indicate the starting height of the lifted
> parcel.
>
> canonical units: m
>
>
> #####
>
> atmosphere_lifting_condensation_level_from_the_surface
>
> The lifting condensation level is the height at which the relative
> humidity of an air parcel cooled by dry adiabatic lifting from the
> surface would reach 100%.
>
> canonical units: m
>
>
> #####
>
> atmosphere_level_of_free_convection
>
> The level of free convection is the altitude where the temperature of
> the environment decreases faster than the moist adiabatic lapse rate
> of a saturated air parcel at the same level. It is calculated by
> lifting a parcel of air dry adiabatically to the LCL (lifting
> condensation level), then moist adiabatically until the parcel
> temperature is equal to the ambient temperature. A coordinate
> variable of original_air_pressure_of_lifted_parcel should be specified
> to indicate the starting height of the lifted parcel.
>
> canonical units: m
>
>
> #####
>
> atmosphere_level_of_free_convection_from_the_surface
>
> The level of free convection is the altitude where the temperature of
> the environment decreases faster than the moist adiabatic lapse rate
> of a saturated air parcel at the same level. It is calculated by
> lifting a parcel of air dry adiabatically from the surface to the LCL
> (lifting condensation level), then moist adiabatically until the
> parcel temperature is equal to the ambient temperature.
>
> canonical units: m
>
>
> #####
>
>
> [update to existing standard_name]
>
> atmosphere_specific_convective_available_potential_energy
>
> 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. "Specific" means per unit mass. Potential energy is the sum of
> the gravitational potential energy relative to the geoid and the
> centripetal potential energy. (The geopotential is the specific
> potential energy.)
>
> canonical units: J kg-1
>
>
> #####
>
> atmosphere_specific_convective_available_potential_energy_from_the_surface
>
> 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. "Specific" means per unit mass. Potential energy is the sum of
> the gravitational potential energy relative to the geoid and the
> centripetal potential energy. (The geopotential is the specific
> potential energy.)
>
> canonical units: J kg-1
>
> #####
>
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----- End forwarded message -----
Received on Mon Jun 17 2013 - 06:49:30 BST
