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

Daniel Neumann daniel.neumann at io-warnemuende.de
Tue Jun 27 06:43:58 MDT 2017

Dear CF-Mailinglist,

in a recent proposal (link given below*), Alison and I discussed about 
the naming conventions for the mass of specific aerosol particle 
components. There seems to be clarification necessary in the 
descriptions and/or names.
[* recent proposal with discussion: 
http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2017/059522.html, look 
for "10. mass_concentration_of_chloride_dry_aerosol_particles_in_air (kg 

Currently, there exist standard names like
 > mass_concentration_of_ammonium_dry_aerosol_particles_in_air
 > mass_concentration_of_dust_dry_aerosol_particles_in_air
 > general form: mass_concentration_of_X_dry_aerosol_particles_in_air
which describe mass concentration of aerosol particles that contain 
species X. Thus, this standard name describes not only the mass of 
species X but also the mass of other species that are associated with X 
on particles. In the past, I thought it would describe the mass of 
species X only. We think that there is a need for clarifying this in the 
description of these standard names.

When we now want to quantify the mass of particulate X only (e.g. mass 
of particulate chloride, mass of particulate ammonium), we could use the 
standard name
 > mass_concentration_of_dry_aerosol_particles_expressed_as_X_in_air

However, I see two problems with respect to this naming convention. 
First, we get a not-nice name if we want to express the mass 
concentrations of particulate ammonium in terms of nitrogen. We needed a 
standard name like
which contains 'expressed' twice.

Second (but that is my personal feeling only), I use the 
"X_expressed_as_Y" formulation only, when there is some relation from Y 
to X. Or in other words: when Y is a reasonable measure for X.
 > ...organic_matter_..._expressed_as_carbon...
 > ...nox_expressed_as_nitrogen...
 > ...phytoplankton_expressed_as_phosphorus...

"mass_concentration_of_dry_aerosol_particles_expressed_as_X_in_air" is 
not a good choice for a standard name describing the mass of particulate 
X in my opinion.

An alternative would be to introduce a standard name like
 > mass_concentrations_of_particulate_X_in_air
 > mass_concentrations_of_particulate_ammonium_in_air
 > mass_concentrations_of_particulate_chloride_in_air

What is your opinion on this topic?

Best Regards,

Daniel Neumann

Leibniz Institute for Baltic Sea Research Warnemuende
Physical Oceanography and Instrumentation
Seestrasse 15
18119 Rostock

phone:  +49-381-5197-287
fax:    +49-381-5197-114 or 440
e-mail: daniel.neumann at io-warnemuende.de

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