Hi Alison,
If a community uses the term 'diameter' then I would stick with that and in our experience with both sediment grain-size and aerosol size spectra 'diameter' is the word exclusively used.
Cheers, Roy.
-----Original Message-----
From: cf-metadata-bounces at cgd.ucar.edu [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of alison.pamment at stfc.ac.uk
Sent: 24 November 2010 13:47
To: cf-metadata at cgd.ucar.edu
Subject: Re: [CF-metadata] Correct name for aerosol size distributionexpressedin numbers ?
Dear Jonathan and Bruno,
I agree with Jonathan's point that the particle size is a geophysical
parameter, so we should not refer to 'bins' in the standard name. I
think 'size' is too ambiguous a term so I vote for
aerosol_particle_radius or aerosol_particle_diameter.
Jonathan is correct that we do have existing standard names that refer
to the effective radius of cloud particles. However, we also have
aerosol name explanations that refer to the particle diameters, e.g.,
the explanation of
atmosphere_optical_thickness_due_to_pm1_ambient_aerosol says "Pm1
aerosol" is an air pollutant with an aerodynamic diameter of less than
or equal to 1 micrometer." Personally, I don't mind whether we refer to
radius or diameter, but if diameter is the most commonly used measure of
aerosols then it makes sense to use it in the name.
Best wishes,
Alison
------
Alison Pamment Tel: +44 1235 778065
NCAS/British Atmospheric Data Centre Fax: +44 1235 446314
Rutherford Appleton Laboratory Email: alison.pamment at stfc.ac.uk
Chilton, Didcot, OX11 0QX, U.K.
> -----Original Message-----
> From: cf-metadata-bounces at cgd.ucar.edu [mailto:cf-metadata-
> bounces at cgd.ucar.edu] On Behalf Of Jonathan Gregory
> Sent: 24 November 2010 12:30
> To: cf-metadata at cgd.ucar.edu
> Subject: [CF-metadata] Correct name for aerosol size
> distributionexpressedin numbers ?
>
> Dear Bruno
>
> > I love simple solutions.
> As physicists, we always think simplicity and elegance imply
> correctness!
>
> > As for the name of the coordinate variable, I would prefer
diameter
> > over size.
> What about radius? There are existing names for radii of cloud
> particles,
> and these are analogous.
>
> > It is usual to call the size classe "bins", so we might come to
> > particle_bins_mid_diameter.
> But here we are discussing the name of a geophysical quantity, which
> you happen
> to be using as an independent coordinate variable. So I think it's
> better to
> call it the aerosol particle size/radius/diameter in the standard
name.
> The
> fact that you are using it in bins is evident from the structure of
the
> data:
>
> dimensions:
> aerosol_particle_bins=30;
> two=2;
> variables:
> int size30(aerosol_particle_bins);
> size30:long_name = "index values from 1 up to 30" ;
> float mic_conctab_SPP200_sync_1(time, aerosol_particle_bins);
> mic_conctab_SPP200_sync_1:units = "count/cm3" ;
> mic_conctab_SPP200_sync_1:coordinates = "size30";
> mic_conctab_SPP200_sync_1:standard_name =
> "number_concentration_of_ambient_aerosol_in_air"
;
> float aerosol_particle_bins(aerosol_particle_bins);
> aerosol_particle_bins:long_name="median diameter of size class";
> aerosol_particle_bins:units="SOMETHING";
> aerosol_particle_bins:standard_name="aerosol_particle_radius";
> aerosol_particle_bins:bounds="aerosol_particle_bin_bounds";
> float aerosol_particle_bin_bounds(aerosol_particle_bins,two);
>
> where the last variable specifies the range of size/diameter/radius
for
> each
> bin.
>
> Best wishes
>
> Jonathan
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> CF-metadata at cgd.ucar.edu
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Received on Wed Nov 24 2010 - 07:16:24 GMT
