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
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Received on Thu May 09 2019 - 06:26:40 BST
