Hello Alison,
I would like to return to the "product_of" terms because Jonathan has, in another thread, drawn attention to the guidelines on the ordering of "X" and "Y" in "product_of_X_and_Y", namely:
If X and Y are both scalars or both components of vectors, they are put in alphabetical order. If one of them is the component
of a vector, it is put first i.e. the vector component is X, the scalar is Y. (
http://cfconventions.org/Data/cf-standard-names/docs/guidelines.html)
The terms we have discussed below involve products of the "lagrangian_tendency_of_air_pressure" .. which I would interpret as the vertical component of the velocity vector in pressure coordinates. I am not convinced that it appropriate to follow the guidelines rigidly here, as that would imply product_of_eastward_wind_and_lagrangian_tendency_of_air_pressure and product_of_lagrangian_tendency_of_air_pressure_and_northward_wind. It would surely be better to use the ordering (1) horizontal, (2) vertical for these terms.
-- This specific problem goes away if we regard
"lagrangian_tendency_of_air_pressure"
as a scalar .. but we run into a similar issue with terms such as product_of_geopotential_height_and_lagrangian_tendency_of_air_pressure and product_of_lagrangian_tendency_of_air_pressure_and_specific_humidity. These are essentially advective fluxes, so I believe we should place the air pressure tendency first.
This would improve consistency with existing terms such as product_of_upward_air_velocity_and_air_temperature.
I.e. I suggest the following names ... the first two as you approved earlier, and the last 3 reversing the order of "X" and "Y":
* product_of_eastward_wind_and_lagrangian_tendency_of_air_pressure
* product_of_northward_wind_and_lagrangian_tendency_of_air_pressure
* product_of_lagrangian_tendency_of_air_pressure_and_specific_humidity
* product_of_lagrangian_tendency_of_air_pressure_and_air_temperature
* product_of_lagrangian_tendency_of_air_pressure_and_geopotential_height
regards,
Martin
________________________________
From: CF-metadata <cf-metadata-bounces at cgd.ucar.edu> on behalf of Jonathan Gregory <j.m.gregory at reading.ac.uk>
Sent: 09 May 2019 13:56
To: cf-metadata at cgd.ucar.edu
Subject: Re: [CF-metadata] Some standard name updates to improve consistency.
Dear Martin
OK. Thanks for explaining and sorry I didn't notice the correct point. I am
happy then.
Best wishes
Jonathan
On Thu, May 09, 2019 at 12:26:40PM +0000, Martin Juckes - UKRI STFC wrote:
> Date: Thu, 9 May 2019 12:26:40 +0000
> From: Martin Juckes - UKRI STFC <martin.juckes at stfc.ac.uk>
> To: Jonathan Gregory <j.m.gregory at reading.ac.uk>,
> "cf-metadata at cgd.ucar.edu" <cf-metadata at cgd.ucar.edu>
> Subject: Re: [CF-metadata] Some standard name updates to improve
> consistency.
>
> Dear Jonathan,
>
>
> On the question of the use of the phrase "ambient_aerosol" when referring to the aerosol itself, rather than to the particles within the aerosol, I fear that my comment which you quote may have become detached from the intended context.
>
>
> I am happy with the distinction between "aerosol" (the suspension of particle in air) and "aerosol_particles" (the particles which are suspended). My comment to Alison referred to the use of the qualifier "ambient" when talking about the aerosol itself: is it necessary or useful?
>
>
> The issue cam up because there are 5 standard names using the phrase "dust_ambient_aerosol_particles_direct_radiative_effect" which I suggested changing to "dust_aerosol_direct_radiative_effect". This would be consistent with the usage in the literature, which would, I believe, make the terms easier to read. In this case, there is nothing wrong with referring to the aerosol suspension. Alison agreed with these points, but would like to retain "ambient", as in "dust_ambient_aerosol_direct_radiative_effect". When talking about particles within an aerosol it is very important to distinguish between measurements representative of their state in the atmospheric suspension vs. the state they might be in after sampling. "ambient", when qualifying "aerosol_particles", means that we are describing the particles as they exist in the aerosol. As a qualification of "aerosol" I can't see that it has any meaning.
>
>
> The 4 terms which you refer to using "aerosol" rather than "aerosol_particles" are ones which Alison agreed to change to include "particles" earlier in this thread. These are all terms which are clearly intended to refer only to the particles.
>
>
> regards,
>
> Martin
>
>
> ________________________________
> From: CF-metadata <cf-metadata-bounces at cgd.ucar.edu> on behalf of Jonathan Gregory <j.m.gregory at reading.ac.uk>
> Sent: 07 May 2019 18:19
> To: cf-metadata at cgd.ucar.edu
> Subject: Re: [CF-metadata] Some standard name updates to improve consistency.
>
> Dear Martin and Alison
>
> Thank you for carefully pursuing this detailed discussion. The degree of
> consistency which Martin remarked upon initially is encouraging, but it's also
> evident that we have to work very hard to achieve that, and any tools that we
> can put in place to make it easier (as Martin is thinking about, I believe)
> are well worth considering.
>
> I have some small points.
>
> > 1. I've looked into the elemental/black carbon issue briefly
> ...
> > it may make sense to deal with that in a separate discussion and try to get some relevant experts involved.
>
> I agree with that conclusion.
>
> > 9. I'm still a little uncomfortable with the idea of "ambient_aerosol" referring to the suspension of particles in air. The phrase "ambient_aerosol_particles" is used when we are referring to properties of the particles rather than the suspension
>
> This is like the distinction between ocean vs sea_water and atmosphere vs air.
>
> > I can't think of a meaningful interpretation of a "dry aerosol" (I think dust_dry_aerosol is only used in the form dust_dry_aerosol_particles).
>
> We have the following names which mention dry_aerosol without particles:
>
> mass_concentration_of_biomass_burning_dry_aerosol_in_air
> mass_fraction_of_mercury_dry_aerosol_in_air
> tendency_of_atmosphere_mass_content_of_mercury_dry_aerosol_due_to_emission
> tendency_of_atmosphere_mass_content_of_sulfate_dry_aerosol_expressed_as_sulfur_due_to_wet_deposition
>
> > For "relative_humidity_for_aerosol_particle_size_selection", I recognise that this would be the only use of "particle" in the singular.
>
> This is a minor concern, but to avoid introducing it in the singular we could
> write relative_humidity_for_size_selection_of_aerosol_particles - that might
> be easier to read as well.
>
> > I suggest we add 'A positive radiative forcing or radiative effect is
> equivalent to a downward radiative flux and contributes to a warming of the
> earth system.'
>
> I agree that for the sake of clarity it would be good to add this. It's
> consistent with literature, as you say, and also with the IPCC AR5 glossary,
> which says, "Radiative forcing is the change in the net, downward minus upward,
> radiative flux ...".
>
> Best wishes
>
> 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 Mon May 13 2019 - 07:34:51 BST
