[CF-metadata] Clarifying standard names for 'mass_concentration_of_*_dry_aerosol_particles'

From: Jonathan Gregory <j.m.gregory>
Date: Fri, 23 Mar 2018 16:31:16 +0000

Dear Daniel

> >Do you mean e.g.
> >mass_fraction_of_ambient_pm10_in_air
> >mass_fraction_of_dry_pm10_in_air
> >mass_fraction_of_water_in_pm10_in_air
> >I'm not sure that I understand, but I don't think ambient = dry + water
> >in this case, because the last one appears to mean the mass fraction of
> >the ambient aerosol which is water. I have a vague recollection of discussing
> >before what this was intended to mean. Do you want to describe the mass
> >fraction of the air which is the water of the ambient aerosol?
> Ah! I interpreted
> "mass_fraction_of_water_in_ambient_aerosol_particles_in_air"
> wrongly. I interpreted it as fraction of
> "water_in_ambient_aerosol_particles" in "air". But actually, it
> means fraction of "water" in "ambient_aerosol_particles_in_air"?

Actually I think you were right, and I was wrong e.g.
  mass_fraction_of_water_in_ambient_aerosol_particles_in_air
must be an example of the pattern
  mass_fraction_of_X_in_air
so X=water_in_ambient_aerosol_particles, as you say. Therefore the sum does
add up as you say. However the definition of this existing standard name does
not comment on the perplexity of two "in"s. I do believe we discussed this
before, but I can't remember when. I wonder whether we could take advantage
of your proposal to change these names in order to remove the problem. What
would read most clearly? For example
  mass_fraction_of_water_contained_within_pm10_in_air
"contained within" is a longer way of saying "content of", which would be
more natural, but I wouldn't suggest that because "content" is used in another
specific sense in standard names (the amount of something per unit area).

Best wishes

Jonathan
Received on Fri Mar 23 2018 - 10:31:16 GMT