Re: [CF-metadata] sea_water_turbidity
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 CentreEmail: alison.pamm...@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-boun...@cgd.ucar.edu] On Behalf Of alison.pamm...@stfc.ac.uk Sent: 11 March 2013 12:37 To: cf-metadata@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 CentreEmail: alison.pamm...@stfc.ac.uk STFC Rutherford Appleton Laboratory R25, 2.22 Harwell Oxford, Didcot, OX11 0QX, U.K. From: CF-metadata [mailto:cf-metadata-boun...@cgd.ucar.edu] On Behalf Of alison.pamm...@stfc.ac.uk Sent: 07 March 2013 12:17 To: cf-metadata@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.pamm...@stfc.ac.uk STFC Rutherford Appleton Laboratory R25, 2.22 Harwell Oxford, Didcot, OX11 0QX, U.K. From: CF-metadata [mailto:cf-metadata-boun...@cgd.ucar.edu] On Behalf Of John Maurer Sent: 07 March 2013 01:19 To: cf-metadata@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 + From: alison.pamm...@stfc.ac.uk To: cf-metadata@cgd.ucar.edu Subject: Re: [CF-metadata] sea_water_turbidity Message-ID: 014539ac4976be4490a360410a8c2017569ec...@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
[CF-metadata] sea_water_turbidity?
Hi Jonathan, Turbidity is a measure of water clarity, the degree to which light entering a column of water is scattered by suspended solids. Suspended solids include things such as mud, algae, plant/animal material, and fecal matter. Factors contributing to water turbidity include soil erosion, elevated nutrient inputs, and waste discharge. Thanks, John Date: Fri, 22 Feb 2013 09:05:38 +1100 From: Jonathan Gregory j.m.greg...@reading.ac.uk To: cf-metadata@cgd.ucar.edu Subject: [CF-metadata] sea_water_turbidity? Message-ID: 20130221220538.gb2...@met.reading.ac.uk Content-Type: text/plain; charset=us-ascii Dear John Thanks for the suggestion. Please could you provide a definition for this quantity? Cheers Jonathan - Forwarded message from John Maurer jmau...@hawaii.edu - Date: Wed, 20 Feb 2013 14:52:11 -1000 From: John Maurer jmau...@hawaii.edu To: cf-metadata@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 ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] sea_water_turbidity?
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-boun...@cgd.ucar.edu] On Behalf Of alison.pamm...@stfc.ac.uk [alison.pamm...@stfc.ac.uk] Sent: 27 February 2013 14:04 To: cf-metadata@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 CentreEmail: alison.pamm...@stfc.ac.ukmailto:j.a.pamm...@rl.ac.uk STFC Rutherford Appleton Laboratory R25, 2.22 Harwell Oxford, Didcot, OX11 0QX, U.K. From: CF-metadata [mailto:cf-metadata-boun...@cgd.ucar.edu] On Behalf Of John Maurer Sent: 21 February 2013 00:52 To: cf-metadata@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 -- Scanned by iCritical. 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. ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
[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 ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
[CF-metadata] sea_water_turbidity?
Dear John Thanks for the suggestion. Please could you provide a definition for this quantity? Cheers Jonathan - Forwarded message from John Maurer jmau...@hawaii.edu - Date: Wed, 20 Feb 2013 14:52:11 -1000 From: John Maurer jmau...@hawaii.edu To: cf-metadata@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 ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
