Dear John, All,
There have been no further comments in the last seven days so sea_water_turbidity (1) is now accepted for inclusion in the standard name table and will be added at the next update.
Best wishes,
Alison
------
Alison Pamment Tel: +44 1235 778065
NCAS/British Atmospheric Data Centre Email: alison.pamment at stfc.ac.uk
STFC Rutherford Appleton Laboratory
R25, 2.22
Harwell Oxford, Didcot, OX11 0QX, U.K.
> -----Original Message-----
> From: CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf
> Of alison.pamment at stfc.ac.uk
> Sent: 11 March 2013 12:37
> To: cf-metadata at cgd.ucar.edu
> Subject: Re: [CF-metadata] sea_water_turbidity
>
> Dear All,
>
> I think we have now reached consensus on this name:
> sea_water_turbidity (units of '1' i.e. dimensionless)
> 'Turbidity is a dimensionless quantity which is expressed in NTU
> (Nephelometric Turbidity Units). Turbidity expressed in NTU is the
> proportion of white light scattered back to a transceiver by the particulate
> load in a body of water, represented on an arbitrary scale referenced
> against measurements made in the laboratory on aqueous suspensions of
> formazine beads. Sea water turbidity may also be measured by the quantity
> with standard name secchi_depth_of_sea_water.'
>
> Unless further comments are received within the next seven days this name
> will be accepted and included in the next update of the standard name
> table.
>
> A cross-reference to the new name will be added to the definition of
> secchi_depth_of_sea_water: 'Sea water turbidity may also be measured by
> the quantity with standard name sea_water_turbidity.'
>
> Best wishes,
> Alison
>
> ------
> Alison Pamment Tel: +44 1235 778065
> NCAS/British Atmospheric Data Centre Email: alison.pamment at stfc.ac.uk
> STFC Rutherford Appleton Laboratory
> R25, 2.22
> Harwell Oxford, Didcot, OX11 0QX, U.K.
>
>
> From: CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf
> Of alison.pamment at stfc.ac.uk
> Sent: 07 March 2013 12:17
> To: cf-metadata at cgd.ucar.edu
> Subject: Re: [CF-metadata] sea_water_turbidity
>
> Dear John,
>
> Thanks for checking. I'm happy with the units of 1 and your amended
> definition.
>
> Best wishes,
> Alison
>
> ------
> Alison Pamment????????????????????????? Tel: +44 1235 778065
> NCAS/British Atmospheric Data Centre??? Email: alison.pamment at stfc.ac.uk
> STFC Rutherford Appleton Laboratory
> R25, 2.22
> Harwell Oxford, Didcot, OX11 0QX, U.K.
>
>
> From: CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf
> Of John Maurer
> Sent: 07 March 2013 01:19
> To: cf-metadata at cgd.ucar.edu
> Subject: [CF-metadata] sea_water_turbidity
>
> Thanks, Alison. After further consideration as well as discussion with some
> of our water quality colleagues, I think the dimensionless units of NTU may
> be better expressed in UDUNITS as "1" instead of "1e-3" (parts per
> thousand) since the values normally range in the 0-10+ range (rather than
> 0.001-0.01+). So, I would modify the units to "1" and slightly modify your
> proposed definition to the following:
>
> 'Turbidity is a dimensionless quantity which is expressed in NTU
> (Nephelometric Turbidity Units). Turbidity expressed in NTU is the
> proportion of white light scattered back to a transceiver by the particulate
> load in a body of water, represented on an arbitrary scale referenced
> against measurements made in the laboratory on aqueous suspensions of
> formazine beads. Sea water turbidity may also be measured by the quantity
> with standard name secchi_depth_of_sea_water.'
>
> Cheers,
> John
>
> Message: 2
> Date: Wed, 6 Mar 2013 12:08:09 +0000
> From: <alison.pamment at stfc.ac.uk>
> To: <cf-metadata at cgd.ucar.edu>
> Subject: Re: [CF-metadata] sea_water_turbidity
> Message-ID:
> ? ? ? ? <014539AC4976BE4490A360410A8C2017569ECD91 at EXCHMBX01.fed.cclrc.
> ac.uk>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Dear John and Roy,
>
> Thanks for your comments. Based on the explanations you have provided I
> suggest that the wording of the definition should be 'Turbidity is a
> dimensionless quantity which is expressed in NTU (Nephelometric Turbidity
> Units), which are normally given as 1e-3 or 0.001 i.e. parts per thousand.
> Turbidity expressed in NTU is the proportion of white light scattered back to
> a transceiver by the particulate load in a body of water, represented on an
> arbitrary scale referenced against measurements made in the laboratory on
> aqueous suspensions of formazine beads. Sea water turbidity may also be
> measured by the quantity with standard name secchi_depth_of_sea_water.'
>
> I suggest also that we could improve the definition of the secchi_depth
> name to make it clearer that the quantity relates to turbidity and add a
> cross-reference to the new name:
> secchi_depth_of_sea_water - ' Depth is the vertical distance below the
> surface. A Secchi disk is a patterned disk that is used to measure water
> transparency, also called turbidity, in oceans and lakes. The disk is lowered
> into the water and the depth at which the pattern is no longer visible is the
> called the secchi depth. Sea water turbidity may also be measured by the
> quantity with standard name sea_water_turbidity.'
>
> Do you agree?
>
> Best wishes,
> Alison
>
> ------
> Alison Pamment ? ? ? ? ? ? ? ? ? ? ? ? ?Tel: +44 1235 778065
> NCAS/British Atmospheric Data Centre ? ?Email: alison.pamment at stfc.ac.uk
> STFC Rutherford Appleton Laboratory
> R25, 2.22
> Harwell Oxford, Didcot, OX11 0QX, U.K.
>
>
> From: CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf
> Of John Maurer
> Sent: 05 March 2013 00:23
> To: cf-metadata at cgd.ucar.edu
> Subject: [CF-metadata] sea_water_turbidity
>
> Yes, I agree with Roy's assessment. Thank you.
> Cheers,
> John
>
> Date: Wed, 27 Feb 2013 21:19:01 +0000
> From: "Lowry, Roy K." <rkl at bodc.ac.uk>
> To: "alison.pamment at stfc.ac.uk" <alison.pamment at stfc.ac.uk>,
> ? ? ? ? "cf-metadata at cgd.ucar.edu" <cf-metadata at cgd.ucar.edu>
> Subject: Re: [CF-metadata] sea_water_turbidity?
> Message-ID:
> ? ? ? ?
> <40829B0E077C1145A6DE44D39B3830A922989BD586 at nerckwmb1.ad.nerc.ac
> .uk>
> Content-Type: text/plain; charset="Windows-1252"
>
> Hello Alison,
>
> I had been hanging back waiting for John to respond to Jonathan's comment,
> because nephelometric turbidity is a phenomenon that I've seen described
> - but not necessarily defined - in a couple of different ways. ?However,
> whilst both turbidity and secchi disk depth (and attenuance to the matter)
> have values related to the SPM load in the water body, they differ markedly
> for a given SPM load and so I think a new standard name is justified.
>
> As a prompt, I'll give one of my understandings of turbidity in NTU, which is
> 'The proportion of white light scattered back to the transceiver by the
> particulate load in a body of water, represented on an arbitrary scale
> referenced against measurements made in the laboratory on aqueous
> suspensions of formazine beads.' ?Before going any further we need John
> to either confirm that this is what he means or come up with an alternative.
> ?Others might also have their own ideas....
>
> Cheers, Roy.
> ______________________________
> __________
> From: CF-metadata [cf-metadata-bounces at cgd.ucar.edu] On Behalf Of
> alison.pamment at stfc.ac.uk [alison.pamment at stfc.ac.uk]
> Sent: 27 February 2013 14:04
> To: cf-metadata at cgd.ucar.edu
> Subject: Re: [CF-metadata] sea_water_turbidity?
>
> Dear John,
>
> Thank you for your proposal.
>
> We currently have one existing standard name relating to turbidity of sea
> water, secchi_depth_of_sea_water, which has units of metres and is
> defined as ?Depth is the vertical distance below the surface. A Secchi disk is
> a patterned disk that is used to measure water transparency in oceans and
> lakes. The disk is lowered into the water and the depth at which the pattern
> is no longer visible is the called the secchi depth.?
>
> I agree with Jonathan that it would be helpful if you could provide a (fairly
> brief) definition for the new name or perhaps a suitable reference.
>
> Best wishes,
> Alison
>
> ------
> Alison Pamment ? ? ? ? ? ? ? ? ? ? ? ? ?Tel: +44 1235 778065
> NCAS/British Atmospheric Data Centre ? ?Email:
> alison.pamment at stfc.ac.uk<
> mailto:J.A.Pamment at rl.ac.uk>
> STFC Rutherford Appleton Laboratory
> R25, 2.22
> Harwell Oxford, Didcot, OX11 0QX, U.K.
>
>
> From: CF-metadata [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf
> Of John Maurer
> Sent: 21 February 2013 00:52
> To: cf-metadata at cgd.ucar.edu
> Subject: [CF-metadata] sea_water_turbidity?
>
> Dear CF-Metadata,
> I would propose the addition of "sea_water_turbidity" to the CF Standard
> Names. This has units of NTU (Nephelometric Turbidity Units), which would
> be represented in UDUNITS as "1e-3" (similar to how sea_water_salinity is in
> PSS (or PSU) and commonly represented as 1e-3).
> Thanks,
> John Maurer
> Data System Administrator
> Pacific Islands Ocean Observing System (PacIOOS)
> University of Hawaii at Manoa
>
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