Re: [CF-metadata] water level with/without datum
Hi Nan, Using unqualified 'water' to signify water within a water body works for me. Cheers, Roy. -Original Message- From: cf-metadata-boun...@cgd.ucar.edu [mailto:cf-metadata-boun...@cgd.ucar.edu] On Behalf Of Nan Galbraith Sent: 25 February 2010 16:47 To: Jonathan Gregory Cc: John Graybeal; cf-metadata@cgd.ucar.edu Subject: Re: [CF-metadata] water level with/without datum Agreed, water_surface_height_above_x is perfect. And simple, as Jeff pointed out earlier this week. I think Roy's example is a relevant use case. Although he has not made a proposal, his data set requires either a new name of river_water_temperature, or a name which can be used for both sea and river. The existing name of sea_water_temperature is not sufficient for the case he described. Roy's example shows the need for a *single name* that can be used for both sea and river temperature, not different names, if I understand his description correctly. I'd like to extend the use of this prospective term to sub-surface water bodies, which, like rivers, don't always have clear boundaries. We have ROVs that travel from lakes and reservoirs through subsurface passages; I don't see any reason to (or reasonable way to) split up the measurements made by these instruments based on which side of an invisible line they're on at any given point. So, I think 'water' is far better than 'sea_lake_river_water'. There are several names that use the modifiers 'atmosphere', 'in_air' and 'surface' to indicate water that's not part of a water body. Does this imply that the unmodified term 'water' means water that's in a water body? The only names I can find that use plain 'water' seem to be sound_intensity and sound_pressure terms - I assume these refer to water in a water body? Is that enough of a precedent to suggest that water_temperature, _velocity, _salinity, etc etc could be standard names for properties of the water in bodies of water? Cheers - Nan water_surface_height_above_x seems to meet all the criteria. -- *** * Nan Galbraith(508) 289-2444 * * Upper Ocean Processes GroupMail Stop 29 * * Woods Hole Oceanographic Institution* * Woods Hole, MA 02543* *** ___ CF-metadata mailing list CF-metadata@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. ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] water level with/without datum
Dear Nan I think Roy's example is a relevant use case. Although he has not made a proposal, his data set requires either a new name of river_water_temperature, or a name which can be used for both sea and river. The existing name of sea_water_temperature is not sufficient for the case he described. Roy's example shows the need for a *single name* that can be used for both sea and river temperature, not different names, if I understand his description correctly. That's right. He needs a single name which covers sea and river. I don't see any reason to (or reasonable way to) split up the measurements made by these instruments based on which side of an invisible line they're on at any given point. Yes. In some applications it is artificial to distinguish between sea, lake, reservoir, river etc. There are several names that use the modifiers 'atmosphere', 'in_air' and 'surface' to indicate water that's not part of a water body. Does this imply that the unmodified term 'water' means water that's in a water body? The only names I can find that use plain 'water' seem to be sound_intensity and sound_pressure terms - I assume these refer to water in a water body? Is that enough of a precedent to suggest that water_temperature, _velocity, _salinity, etc etc could be standard names for properties of the water in bodies of water? I don't remember the intention of those standard names. I am surprised that they don't say sea or river if that's what they meant. I am sorry to be obstinate on this, but I don't think that it would be right to assume that water without any qualifier meant water that is part of a water body. As I said in a previous email, we always try to indicate the context explicitly in standard names, to make them self-describing. This use of water would be a kind of definition by omission, rather than explicitly. I think that our discussion so far indicates that we should keep the existing sea names, and add corresponding new names for water bodies in general (as and when they are requested). We can likewise add new sea names. Therefore I think we have to decide what to call the new names. Roy suggested water body. As I've said before, I would prefer sea/lake/river_water (or with some other punctuation) to water_body_water, because sea/lake/river_water is more self-explanatory, and the repetition of water in water_body_water is clumsy and possibly confusing. I can imagine someone not being sure how to parse water body water temperature when they first come across it. As Roy said, / could be a problem, although it's legal for netCDF. It does make the intention clearer, since / means or. It could be spelled out, at the cost of greater length, as sea_or_lake_or_river_water. best wishes Jonathan ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] water level with/without datum
Dear Jeff After more internal discussion we feel that the single name 'water_surface_height_above_reference_datum' would meet our needs admirably (i.e., no separate name for the station datum case). Very good. Is this an arbitrary local reference datum? I think that would be the right name, if so. If it's the geoid or some tide level, I think that should be indicated in the name. That's because quantities with these different datums do not differ by a constant, and could not be regarded as the same geophysical quantity, so should have different standard names. Best wishes Jonathan ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] water level with/without datum
Therefore I think we have to decide what to call the new names. Roy suggested water body. As I've said before, I would prefer sea/lake/river_water (or with some other punctuation) to water_body_water, because sea/lake/river_water is more self-explanatory, and the repetition of water in water_body_water is clumsy and possibly confusing. I can imagine someone not being sure how to parse water body water temperature when they first come across it. Instead of a prefix modifer, how about adding _body as a postfix modifier? So you could have sea_water_temperature for oceans and water_body_temperature for oceans, rivers, lakes, and other significant accumulations of liquid water. Cheers, Seth McGinnis NARCCAP Data Manager ISSE / ISP / IMAGe / CISL / NCAR (P.S.: Observation/tangent: It seems like this conundrum may be arising in part because the day-to-day meaning of the term water -- liquid H2O -- is at odds with the definition given in the standard name guidelines of water in all phases if not otherwise qualified. Were there a blank slate, I would suggest using the unqualified term to mean liquid water, in better alignment with its commonsense meaning, and coming up with a new term for the more restricted contexts where one needs to refer to all three phases. How frequently in current usage does the all phases sense differ fom the usual sense? Would it be worth considering a switch? That would be an alternate way around the issue of generic water bodies.) ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
