Hi Bryan,
Steve's query presents something of a Standard Names crossroads. 'Chlorophyll' is a very generic word covering a group of pigments (chlorophyll-a, chlorophyll-b, divinyl chlorophyll-a, etc.) that some analytical techniques can resolve whilst others cannot. 'Chlorophyll' is also a proxy for 'phytoplankton' biomass, which brings us into the semantics of the word 'phytoplankton': for some methodologies it is anything small and green, but other methodologies are quite selective about the plankton community for which chlorophyll is a proxy (e.g. chlorophyll extracted from a 20um filter is dominantly from diatoms).
As I see it we can either keep the Standard Name very generic (as you suggest and my gut tells me you're right) and use the long name to spell out the gory details or go down the road I have taken with the BODC PUV which currently has 176 'chlorophyll' parameters. The only problem with the simple (feasible?) approach is that some communities are moving towards using the Standard Name as the parameter identifier and it's inevitable that somebody somewhere will produce a file containing two types of 'chlorophyll' with the expectation that the Standard Name will identify and distinguish them. Do we need some expectation management to discourage this?
Incidentally, I'm wondering where Steve got his definition of 'concentration_of_suspended_matter_in_sea_water' (which incidentally was deprecated in version 12 and replaced by mass_concentration_of_suspended_matter_in_sea_water) from. The definition I have (and I checked it's the same in the HTML version on the CF site) for mass_concentration_of_suspended_matter_in_sea_water is 'Mass concentration means mass per unit volume and is used in the construction mass_concentration_of_X_in_Y, where X is a material constituent of Y. A chemical species denoted by X may be described by a single term such as 'nitrogen' or a phrase such as 'nox_expressed_as_nitrogen', which makes no mention of ''Determined by filtration, drying and then weighing'.
Cheers, Roy.
-----Original Message-----
From: cf-metadata-bounces at cgd.ucar.edu [mailto:cf-metadata-bounces at cgd.ucar.edu] On Behalf Of Bryan Lawrence
Sent: 28 July 2009 19:17
To: cf-metadata at cgd.ucar.edu
Subject: Re: [CF-metadata] Standard name definitions ... are these formal or flexible
Hi Stephen
Alison is buried with CMIP5 problems at the moment, so may not get to this query for a wihle. For my tuppence worth, the method by which something is measured should not be in the definition, since the standard name is supposed to be a geophysical quantity, however measured. We've been over this ground other times.
So, I think there is a case to fix the definition here ... (he says, knowing nothing about the ins and outs of this specific example).
Bryan
On Tuesday 28 July 2009 12:01:20 Stephen Emsley wrote:
> Hi all
>
>
>
> I am currently sifting through the Standard Name table for potential candidates for naming geophysical products for a remote sensing satellite (ESA/GMES Sentinel 3). One of our data products is the concentration of suspended matter in sea water (TSM). I note that there is a standard name for the same. However, on examining the description for this standard name I discover the phrase 'Determined by filtration, drying and then weighing'.
>
>
>
> My question is: How formally defined are the standard names? Could a satellite derived TSM concentration have a standard name concentration_of_suspended_matter_in_sea_water or must a new standard name be devised and proposed that, for instance, includes _from_satellite. Or, rather than proposing a new standard name, would our proposal be to widen the definition of the standard name currently within the table by removing the phrase concerning its measurement.
>
>
>
> Similarly, the concentration_of_chlorophyll_in_seawater description targets in vitro assay using HPLC or fluorimetry and specifies Chlorophyll-a rather than the assemblage of pigments that would be detected using spectrometry from satellite.
>
>
>
> Any advice appreciated. Are there any satellite ocean colour people on the list pondering the same questions vis-?-vis naming data products?
>
>
>
> Many thanks
>
> Steve
>
>
>
> -------------------------------------------------------------------------------------------------
>
> Dr Stephen Emsley
>
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>
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>
> Tamar Science Park Fax: +44 (0)1752 772 227
>
> Derriford, Plymouth, PL6 8BY SEmsley at argans.co.uk <mailto:SEmsley at argans.co.uk>
>
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>
> --------------------------------------------------------------------------------------------------
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--
Bryan Lawrence
Director of Environmental Archival and Associated Research
(NCAS/British Atmospheric Data Centre and NCEO/NERC NEODC)
STFC, Rutherford Appleton Laboratory
Phone +44 1235 445012; Fax ... 5848;
Web: home.badc.rl.ac.uk/lawrence
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Received on Wed Jul 29 2009 - 02:19:28 BST
