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

[John Maurer]

Hi all,
This is a request to have a new standard_name added to the CF table for the
following parameter:

standard_name: colored_dissolved_organic_matter
alias: chromophoric_dissolved_organic_matter
alias: cdom
units: QSDE

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.

More about the units (QSDE):

Sensors are commonly calibrated against a 100 parts per billion (ppb)
quinine sulfate dihydrate solution, a fluorescent 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.

Thanks,
John Maurer
Pacific Islands Ocean Observing System (PacIOOS)
University of Hawaii at Manoa

[Jonathan Gregory]

Dear John

Thanks for the proposal. It would be good to add some more context, in the
style of other CF standard_names. I would suggest
concentration_of_colored_dissolved_organic_matter_in_sea_water
if that makes sense to you. Even so, "concentration" is rather vague - we
usually make it clear whether it's mole concentration or mass concentration,
for instance. To be really explicit (and long) we could say
concentration_of_colored_dissolved_organic_matter_in_sea_water_expressed_as_equivalent_mass_fraction_of_quinine_sulfate_dihydrate
if I understand your description correctly. Is that correct?

Since qsde is not a udunit, I think the canonical unit for this quantity
should be 1 i.e. it is dimensionless, and the definition can make clear
what the unit means. In practice you could give 1e-9 as the unit, which is
equivalent to 1 i.e. both are dimensionless.

Best wishes

Jonathan

Date: Wed, 23 Mar 2016 09:12:28 -1000
Subject: [CF-metadata] request for new CF standard_name: CDOM
Hi all,
This is a request to have a new standard_name added to the CF table for the
standard_name: colored_dissolved_organic_matter
alias: chromophoric_dissolved_organic_matter
alias: cdom
units: QSDE
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 fluorescent 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.
Thanks,
John Maurer
Pacific Islands Ocean Observing System (PacIOOS)
University of Hawaii at Manoa
_______________________________________________
CF-metadata mailing list
http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata

----- End forwarded message -----

[Lowry, Roy K.]

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.

Please note that I partially retired on 01/11/2015. I am now only working 7.5 hours a week and can only guarantee e-mail response on Wednesdays, my day in the office. All vocabulary queries should be sent to ***@bodc.ac.uk. Please also use this e-mail if your requirement is urgent.

________________________________________
From: CF-metadata <cf-metadata-***@cgd.ucar.edu> on behalf of Jonathan Gregory <***@reading.ac.uk>
Sent: 24 March 2016 19:47
To: cf-***@cgd.ucar.edu
Subject: [CF-metadata] request for new CF standard_name: CDOM

Dear John

Thanks for the proposal. It would be good to add some more context, in the
style of other CF standard_names. I would suggest
concentration_of_colored_dissolved_organic_matter_in_sea_water
if that makes sense to you. Even so, "concentration" is rather vague - we
usually make it clear whether it's mole concentration or mass concentration,
for instance. To be really explicit (and long) we could say
concentration_of_colored_dissolved_organic_matter_in_sea_water_expressed_as_equivalent_mass_fraction_of_quinine_sulfate_dihydrate
if I understand your description correctly. Is that correct?

Since qsde is not a udunit, I think the canonical unit for this quantity
should be 1 i.e. it is dimensionless, and the definition can make clear
what the unit means. In practice you could give 1e-9 as the unit, which is
equivalent to 1 i.e. both are dimensionless.

Best wishes

Jonathan

Date: Wed, 23 Mar 2016 09:12:28 -1000
Subject: [CF-metadata] request for new CF standard_name: CDOM
Hi all,
This is a request to have a new standard_name added to the CF table for the
standard_name: colored_dissolved_organic_matter
alias: chromophoric_dissolved_organic_matter
alias: cdom
units: QSDE
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 fluorescent 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.
Thanks,
John Maurer
Pacific Islands Ocean Observing System (PacIOOS)
University of Hawaii at Manoa
_______________________________________________
CF-metadata mailing list
http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata

----- End forwarded message -----
_______________________________________________
CF-metadata mailing list
CF-***@cgd.ucar.edu
http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
________________________________
This message (and any attachments) is for the recipient only. NERC is subject to the Freedom of Information Act 2000 and the contents of this email and any reply you make may be disclosed by NERC unless it is exempt from release under the Act. Any material supplied to NERC may be stored in an electronic records management system.
________________________________