[CF-metadata] request for new CF standard_name: CDOM

From: alison.pamment at stfc.ac.uk <alison.pamment>
Date: Tue, 19 Apr 2016 11:04:36 +0000

Dear John, Jonathan and Roy,

Thanks for the discussion of this name, which I think has been mostly agreed:

concentration_of_colored_dissolved_organic_matter_in_sea_water_expressed_as_equivalent_mass_fraction_of_quinine_sulfate_dihydrate (canonical units: 1)

For the definition, I was planning to simply use the text from John's original proposal:
' The quantity concentration_of_colored_dissolved_organic_matter_in_sea_water_expressed_as_equivalent_mass_fraction_of_quinine_sulfate_dihydrate, is also commonly known as chromophoric_dissolved_organic_matter or CDOM. CDOM plays an important role in the carbon cycling and biogeochemistry of coastal waters. It occurs naturally in aquatic environments primarily as a result of tannins released from decaying plant and animal matter, which can enter coastal areas in river run-off containing organic materials leached from soils. When present in high concentrations, it imparts a brown or yellowish color to water. Its presence can negatively impact fish populations by reducing dissolved oxygen concentrations to harmful levels and by releasing nutrients and metals that contaminate the water. Increased understanding of the role of CDOM will further our ability to manage and protect coastal ecosystems. Sensors are commonly calibrated against a 100 parts per billion (ppb) quinine sulfate dihydrate solution, a fluoresce
nt reference standard commonly used with CDOM sensors. CDOM sensors therefore report in "QSDE" (quinine sulfate dihydrate equivalents). It is important to note, however, that CDOM concentrations in QSDE are not necessarily equivalent to the in situ CDOM concentrations in ppb.'

I'm wondering whether to leave in the last two sentences about units, since we decided that CF canonical units should be '1' (dimensionless). Do you think it's better to keep that text or will it just cause confusion for CF users?

If we can finalise the definition then this name can be accepted for publication in the standard name table.

Best wishes,
Alison

------
Alison Pamment Tel: +44 1235 778065
Centre for Environmental Data Analysis Email: alison.pamment at stfc.ac.uk
STFC Rutherford Appleton Laboratory
R25, 2.22
Harwell Campus, Didcot, OX11 0QX, U.K.


From: CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of John Maurer
Sent: 30 March 2016 20:37
To: cf-metadata at cgd.ucar.edu
Cc: Jonathan Gregory
Subject: Re: [CF-metadata] request for new CF standard_name: CDOM

Thanks, Jonathan and Roy! Your suggestions sound fine by me.
Cheers,
John Maurer
Pacific Islands Ocean Observing System (PacIOOS)
University of Hawaii at Manoa


Date: Fri, 25 Mar 2016 09:05:08 +0000
From: "Lowry, Roy K." <rkl at bodc.ac.uk>
To: Jonathan Gregory <j.m.gregory at reading.ac.uk>,
? ? ? ? "cf-metadata at cgd.ucar.edu" <cf-metadata at cgd.ucar.edu>
Subject: Re: [CF-metadata] request for new CF standard_name: CDOM
Message-ID:
? ? ? ? <HE1PR0601MB1946C0D26C72EB4099D0EFA799830 at HE1PR0601MB1946.eurprd06.prod.outlook.com>

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Dear Jonathan,

Although long-winded your suggestion of:

concentration_of_colored_dissolved_organic_matter_in_sea_water_expressed_as_equivalent_mass_fraction_of_quinine_sulfate_dihydrate

has the great advantage of preventing any confusion between this measurement and a true CDOM concentration determined by some other method. Having mass_fraction in there is particularly valuable as when we encountered this measurement the stock solutions used to calibrate the sensors had the QSD concentrations expressed in nM rather than ppb.

I also agree dimensionless is the best choice for the Canonical Unit.

Cheers, Roy.
Received on Tue Apr 19 2016 - 05:04:36 BST