[CF-metadata] Standard name definitions ... are these formal or flexible
Dear all I agree with this statement of Bryan's: My feeling is that people should mark up their data with standard names that most accurate define what has been measured I think there is a corollary, that we have standard names of various degrees of precision, for different purposes. If some kinds of measurement or model do not distinguish different types of chlorophyll, or if the distinction is immaterial in a particular application, that means the quantities involving these different types of chlorophyll are comparable quantities. Hence they should have the same standard name, since we give the same standard name to quantities which are intended to be comparable. However if in other applications a distinction has to be drawn, we then need distinct standard names for them. Standard names should be introduced for the purposes required, rather than being a lexicon which dictates what is allowed to be described. I also agree with Bryan that standard names for geophysical quantities should not indicate how the measurement is done. There is another issue, which we have been debating, about standard names for raw or uncalibrated measurements; these quantities are not really geophysical - properties of the world - but properties of the measurement apparatus or dataset. Cheers Jonathan ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] Standard name definitions ... are these formal or flexible
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-boun...@cgd.ucar.edu [mailto:cf-metadata-boun...@cgd.ucar.edu] On Behalf Of Bryan Lawrence Sent: 28 July 2009 19:17 To: cf-metadata@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-à-vis naming data products? Many thanks Steve - Dr Stephen Emsley ARGANS Limited Tel: +44 (0)1752 764 289 Unit 3 Drake Building Mobile: +44 (0)7912 515 418 Tamar Science Park Fax: +44 (0)1752 772 227 Derriford, Plymouth, PL6 8BY sems...@argans.co.uk mailto:sems...@argans.co.uk Skype(tm): archonsme
Re: [CF-metadata] Standard name definitions ... are these formal or flexible
Hi Roy Glad that it looks like Steve's specfiic problem isn't a problem given the name change and definition you found. However: You've opened Pandora's box a bit (we've been hammering around the edges for a while). I can feel the o-word coming on ... It's been incoming in the family chemistry sense, and in clouds, and anywhere where we have a geophysical quantity that has a generic type and specific sub-types. In the chemistry case it's about what equations the model can support, and in the observation cases it can be about distinguishing between what can be observed - some things can only observe/simulate at the generic level, others at more specific levels. My feeling is that people should mark up their data with standard names that most accurate define what has been measured (but not how). However, to compare things in this situation we need the relationships between the standard names ... so folk wanting to compare apples and oranges can do so at the fruit level. 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? Well, no, if they are two different types of chlorophyll then there should be two different standard names (or 176), but it should also be clear that they are types of chlorophyll ... and we should have a standard name for that, but the data wouldn't neeed to be marked up with it, that'd be implicit in the relationships that we standardise. That seems like an obvious goal ... Bryan -- 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 ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] Standard name definitions ... are these formal or flexible
Hi Bryan, We have the technology and some of the content. I have been maintaining a mapping between the Parameter Discovery Vocabulary (PDV) used by SeaDataNet and Standard Names to allow us to automatically populate SeaDataNet metadata documents from CF data files. (I do have to confess that doing this for the version 12 new term explosion is currently in my 'pending' tray). The PDV is populated with grouping terms like 'Metal concentrations in the atmosphere', which is represented by the URL http://vocab.ndg.nerc.ac.uk/term/P021/current/MTAT The resulting document gives matches to about 25 Standard Names (the URLs with 'P071' in them) as well as GCMD (P041), SeaDataNet parameter groups (P031) ISO topic categories (P051) and BODC usage vocabulary terms (P011). The grouping terms and mappings have been done by me and are therefore limited by my knowledge of the atmospheric science domain. Suggestions for additional grouping terms (together with the Standard Names that should be included) or suggestions for modifications to what I've already done from the CF community would be welcomed. Cheers, Roy. -Original Message- From: Bryan Lawrence [mailto:bryan.lawre...@stfc.ac.uk] Sent: 29 July 2009 09:56 To: Lowry, Roy K Cc: cf-metadata@cgd.ucar.edu Subject: Re: [CF-metadata] Standard name definitions ... are these formal or flexible Hi Roy Glad that it looks like Steve's specfiic problem isn't a problem given the name change and definition you found. However: You've opened Pandora's box a bit (we've been hammering around the edges for a while). I can feel the o-word coming on ... It's been incoming in the family chemistry sense, and in clouds, and anywhere where we have a geophysical quantity that has a generic type and specific sub-types. In the chemistry case it's about what equations the model can support, and in the observation cases it can be about distinguishing between what can be observed - some things can only observe/simulate at the generic level, others at more specific levels. My feeling is that people should mark up their data with standard names that most accurate define what has been measured (but not how). However, to compare things in this situation we need the relationships between the standard names ... so folk wanting to compare apples and oranges can do so at the fruit level. 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? Well, no, if they are two different types of chlorophyll then there should be two different standard names (or 176), but it should also be clear that they are types of chlorophyll ... and we should have a standard name for that, but the data wouldn't neeed to be marked up with it, that'd be implicit in the relationships that we standardise. That seems like an obvious goal ... Bryan -- 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 -- 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
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-à-vis naming data products? Many thanks Steve - Dr Stephen Emsley ARGANS Limited Tel: +44 (0)1752 764 289 Unit 3 Drake Building Mobile: +44 (0)7912 515 418 Tamar Science Park Fax: +44 (0)1752 772 227 Derriford, Plymouth, PL6 8BY sems...@argans.co.uk mailto:sems...@argans.co.uk Skype(tm): archonsme -- -- 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 ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
