Dear Alison,

I think I and then Olivier tried to define names for optical quantities along 
the same suite of European projects, and this several times since for some 
reasons they were not included in the standard table. It would be nice to 
conclude on this issue.

volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_phytoplankton
I agree that this is fine.

volume_backwards_scattering_coefficient_of_radiative_flux_in_sea_water_due_to_particles
agree with the point on particles. So the name is still fine for me.

For the rest, I'd recommend:
volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_dissolved_organic_matter_and_non_pigmented_particles;
volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_dissolved_organic_matter;
 (if not defined already)
volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_non_pigmented_particles;
The first one is the sum of the other 2, and is a standard satellite product 
(the other 2 terms are not easily distinguishable from space).

I'd favor 'pigmented' rather than 'non_algal'. They are in practice synonymous 
but the reference to pigments is closer to actual laboratory measurements where 
bleaching is used before measuring this contribution of the total particulate 
absorption.

OK for the point on the wavelength.

I agree with all of Roy's comments. 'biogenic' is from biological origin; so I 
would assume that this is synonymous with 'organic' WHEN speaking of particles.
I hope this helps,
Best,
Frédéric

-----Original Message-----
From: alison.pamm...@stfc.ac.uk [mailto:alison.pamm...@stfc.ac.uk] 
Sent: Wednesday, December 18, 2013 1:26 PM
To: m...@pml.ac.uk; olau...@cls.fr; frederic.me...@jrc.ec.europa.eu; 
cf-metadata@cgd.ucar.edu
Cc: victoria.benn...@stfc.ac.uk
Subject: Ocean colour standard names

Dear Mike, Olivier, Frederic, All,

I've been doing some detective work in response to an enquiry from Mike Grant 
of Plymouth Marine Laboratory regarding some ocean colour standard names that 
were causing the CF checker to fail because they are not present in the 
standard name table. Apologies for the length of this email, but the picture 
regarding these names is rather complicated. I would appreciate some help in 
sorting them out.

The names causing the checker to fail are:
> ERROR (3.3): Invalid standard_name:
> 
> volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_ph
> ytoplankton
>
> ERROR (3.3): Invalid standard_name:
>
> volume_backwards_scattering_coefficient_of_radiative_flux_in_sea_water
> _due_to_particles

Mike has pointed out that these names were proposed in 2009/10. In fact, they 
seem to have been proposed twice, first by Frederic Melin and again by Olivier 
Lauret along with a few other names,  but they were never properly agreed which 
I think is the reason they never made it into the standard name table. Clearly, 
however, there is a need to revisit the discussions.

Olivier proposed the following names in December 2010:
number_content_of_icebergs (m-2)
mass_concentration_of_inorganic_particles_in_sea_water (kg m-3) 
volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_dissolved_organic_matter_and_non_algal_particles
 (m-1) 
volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_phytoplankton
 (m-1) 
volume_backwards_scattering_coefficient_of_radiative_flux_in_sea_water_due_to_particles
 (m-1)

Of these, the first name was discussed, eventually accepted in the form of 
number_of_icebergs_per_unit_area and added to the standard name table. The 
other four proposals do not seem to have received any comment at that time.

Earlier, in September 2009 
(http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2009/053225.html) Frederic 
had proposed: 
volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_dissolved_organic_matter_and_non_algal_particles
volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_phytoplankton
volume_backwards_scattering_coefficient_of_radiative_flux_in_sea_water_due_to_particles
volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_non_algal_particles
the first three of which are also in Olivier's list.

The only discussion centred on whether the coefficients were spectral 
quantities (per_unit_wavelength) or whether they simply needed a coordinate 
variable of radiation_wavelength specifying to which wavelength they apply. I 
think the latter was decided.

In June 2010 Frederic re-proposed the names:
volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_dissolved_organic_matter_and_non_pigmented_particles;
volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_phytoplankton;
volume_backwards_scattering_coefficient_of_radiative_flux_in_sea_water_due_to_particles;
volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_non_pigmented_particles;
in which it appears that 'non_algal_particles' had been replaced by 
'non_pigmented_particles', but again there don't seem to have been any comments.

I'm not sure why one set of proposals refers to 'non_algal' and the other 
refers to 'non-pigmented' and no definitions ever seem to have been supplied 
for either. Perhaps Mike, Frederic or Olivier can help with this? Also are 
these particles organic or inorganic or perhaps both?

The two names that Mike is  currently trying to use are 
volume_absorption_coefficient_of_radiative_flux_in_sea_water_due_to_phytoplankton
 and 
volume_backwards_scattering_coefficient_of_radiative_flux_in_sea_water_due_to_particles,
 which actually look OK to me.

We have existing phytoplankton names with the definition: 'Phytoplankton are 
autotrophic prokaryotic or eukaryotic algae that live near the water surface 
where there is sufficient light to support photosynthesis.' I think the 
phytoplankton name can be accepted and added at the next update of the standard 
name table.

I would assume that 'particles' refers to all particles, whether 
organic/inorganic, algal/non-algal, pigmented/non-pigmented. If Mike, Frederic 
or Olivier could confirm my assumption then I think 
volume_backwards_scattering_coefficient_of_radiative_flux_in_sea_water_due_to_particles
 could also be accepted and added to the table.

The other names look reasonable, but we do need to be clear about the 
definitions before they can be accepted (and also whether they are 'non_algal' 
or 'non_pigmented').

I should also mention that in the new year I would like to review the way we 
refer to particles in sea_water as we seem to have a varied terminology: 
particulate_organic_matter, organic_detritus and particulate_biogenic_matter 
all seem to be in current use. I'd like to establish whether we need all these 
or whether we can standardise the names further, particularly as the question 
is relevant to a current set of proposals from John Graybeal.

Best wishes,
Alison

------
Alison Pamment                          Tel: +44 1235 778065
NCAS/British Atmospheric Data Centre    Email: alison.pamm...@stfc.ac.uk
STFC Rutherford Appleton Laboratory     
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.

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