Hi Alison,
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.
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?
Thanks,
--Seth
On 11/7/13 4:52 AM, alison.pamment at stfc.ac.uk wrote:
> Dear Seth, All,
>
> I have reviewed these proposals along with Jonathan W's stability
> index names. The CIN, LFC and LCL proposals are in good shape and can
> be accepted.
>
> The following standard names will be added at the next update.
>
> 1) atmosphere_convective_inhibition (J kg-1)
>
> ' Convective inhibition is the amount of energy per unit mass
> 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.'
>
> 2) atmosphere_convective_inhibition_wrt_surface (J kg-1)
>
> 'Convective inhibition is the amount of energy per unit mass 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.'
>
> 3) atmosphere_lifting_condensation_level (m)
>
> '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.'
>
> 4) atmosphere_lifting_condensation_level_wrt_surface (m)
>
> '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%.'
>
> 5) atmosphere_level_of_free_convection (m)
>
> '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 (lifted
> 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.'
>
> 6) atmosphere_level_of_free_convection_wrt_surface (m)
>
> '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.'
>
> The two proposed CAPE parameters are agreed in principle:
>
> 7) atmosphere_convective_available_potential_energy (J kg-1)
>
> '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.'
>
> 8) atmosphere_convective_available_potential_energy_wrt_surface (J
> kg-1)
>
> '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.'
>
> There is still a question mark as to whether the existing name
> atmosphere_specific_convective_available_potential_energy should be
> made an alias of proposal (7) or (8). Once we can resolve that
> question the names can be added. Please see
> http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2013/056725.html
> and
> http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2013/056730.html
> for the most recent comments on this topic.
>
> 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.
>
>
>> -----Original Message----- From: CF-metadata
>> [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of Seth
>> McGinnis Sent: 01 July 2013 23:49 To: Jonathan Gregory;
>> cf-metadata at cgd.ucar.edu Subject: Re: [CF-metadata] new standard
>> names for CIN, LFC,LCL; update to CAPE
>>
>> Hi Jonathan,
>>
>> Frankly, no, I'm not certain. My thinking is that if anyone is
>> using the existing standard_name, their data is somewhat
>> underspecified, and since it could in principle be one of many
>> types of CAPE, it would be preferable to point to the more generic
>> name.
>>
>> If anybody on the mailing list has an opinion about whether
>> generic "CAPE" would make you think surface-based or something
>> else, please speak up!
>>
>> (Because to be honest, I'm not much of an expert either; I just
>> have some data that I need to make CF-compliant, and have been
>> learning this topic as I go.)
>>
>> On the plus side, I suspect the question of where the alias points
>> may well be entirely moot; the only CAPE data I've been able to
>> find in netcdf form "in the wild" is CF-1.0 and has an empty
>> standard_name.
>>
>> Cheers,
>>
>> --Seth
>>
>>
>> On Mon, 1 Jul 2013 18:08:23 +0100 Jonathan Gregory
>> <j.m.gregory at reading.ac.uk> wrote:
>>> Dear Seth
>>>
>>> It seems fine to delete "specific", I agree. The new names look
>>> good to me.
>>>
>>> Are you sure that
>>>> atmosphere_specific_convective_available_potential_energy
>>> should be an alias of
>>>> atmosphere_convective_available_potential_energy
>>> and not of
>>>> atmosphere_convective_available_potential_energy_wrt_surface
>>> Which is the more likely understanding of the existing name? (I
>>> don't know - you're the expert!)
>>>
>>> Best wishes and thanks
>>>
>>> Jonathan _______________________________________________
>>> CF-metadata mailing list CF-metadata at cgd.ucar.edu
>>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
>>
>> _______________________________________________ CF-metadata mailing
>> list CF-metadata at cgd.ucar.edu
>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Received on Fri Nov 08 2013 - 13:31:36 GMT
