Hi Nan, That is a reasonably convincing use case for adding sea_water_practical_salinity_at_sea_floor. It's the first time I've encountered a desire to label near-bed observations differently from those elsewhere in the water column but can see what you're wanting to do . The strategy I used in the past involved loading data up into a relational database then using a filter algorithm based on measurement depth,water depth and benthic boundary layer thickness (which can vary from 2 m to 50 m depending upon the water column structure and the purpose for which the data are being used).
For model data, it's easy to define 'at sea floor' - it's the bottom cell in a full-depth profile. For measurements I agree with you that quantifying 'at sea floor' isn't a good idea based on my experiences described above. Would it be helpful for measurements to use the phrase 'within the benthic boundary layer'? Cheers, Roy. I have now retired but will continue to be active through an Emeritus Fellowship using this e-mail address. ________________________________ From: CF-metadata <[email protected]> on behalf of Nan Galbraith <[email protected]> Sent: 12 September 2019 17:13 To: [email protected] <[email protected]> Cc: OceanSITES Data Management Team <[email protected]> Subject: Re: [CF-metadata] new variable name request Hi all - I'd like to second (or third ... ) the request for new standard names for sea_water_practical_salinity_at_sea_floor and sea_water_temperature_at_sea_floor. In the OceanSITES project, we deploy CTDs on mooring anchors, and it would be good to be able to find these records, among all the water temperature and practical salinity data sets on our servers. We supply a measurement depth, but it isn't useful for this search, since the water depth isn't mandatory in our format spec. These records are not exactly on the sea floor, but within a few meters; do we need to apply some limit to the distance? I'm thinking about the various sea_surface_temperature variants, surface_skin and surface_subskin, but I'm assuming this isn't needed for sea floor measurements. Thanks - Nan On 9/10/19 1:59 PM, Lowry, Roy K. wrote: > Hi again, > > I place great weight on the phrase 'where appropriate'. If a model > works out electrical conductivity and then uses the PSS-78 algorithms > to compute the salinity then using 'practical salinity' would be > appropriate, but these are far from the norm!!! It's observational > measurements where we really need to be careful about the types of > salinity, but I've yet to see a measurements data set where bottom > salinities are tagged differently from the salinities measured > elsewhere in the water column. Consequently I don't see the need for > the new name. > > Cheers, Roy. > > I have now retired but will continue to be active through an Emeritus > Fellowship using this e-mail address. > > > ------------------------------------------------------------------------ > *From:* Andrew Barna <[email protected]> > *Sent:* 10 September 2019 18:47 > *Subject:* Re: [CF-metadata] new variable name request > Thanks Roy, > > All the existing “sea_water_salinity” names have the sentence "The > more precise standard names should be used where appropriate for both > modelled and observed salinities.” So it think it was worth the ask if > they know. > > -Barna > > > On 2019-09-10, at 07:42, Lowry, Roy K. <[email protected]> wrote: > > > > Dear Barna, > > > > Perhaps the existing Standard Name would suffice for Cathy's needs > as she is labelling model output and the models in my experience do > not work to a specific measurement scale. This is because boundary > condition and assimilation data sets can include measurements of more > than one type in order to provide adequate coverage. > > > > Cheers, Roy. > > > > > > From: CF-metadata <[email protected]> on behalf of > Andrew Barna <[email protected]> > > Sent: 10 September 2019 18:23 > > Subject: Re: [CF-metadata] new variable name request > > > > Hi Cathy, > > > > There is already the name `sea_water_salinity_at_sea_floor` in the > CF standard name list. However, if you know the scale you are > calculating, a new name should be added to indicate this: > > sea_water_practical_salinity_at_sea_floor if using PSS-78 > > or > > sea_water_absolute_salinity_at_sea_floor if using TEOS-10 > > > > I can come up with some definitions if you would like to have either > of these proposed to the list. > > -Barna > > > > > > > On 2019-09-10, at 07:04, Cathy Smith <[email protected]> wrote: > > > > > > Thanks. I will use that variable. > > > > > > I also calculated salinity of the ocean floor. Same question. > > > > > > Cathy > > > > > > On 9/9/19 3:44 PM, Andrew Barna wrote: > > >> Hi Cathy, > > >> > > >> There is the name `sea_water_potential_temperature_at_sea_floor` > with the following definition: > > >> Potential temperature is the temperature a parcel of air or sea > water would have if moved adiabatically to sea level pressure. The > potential temperature at the sea floor is that adjacent to the ocean > bottom, which would be the deepest grid cell in an ocean model. > > >> > > >> From what I can tell, there is no “in situ” sea water temperature > name at the sea floor. I’d suggest the following name for this > parameter with canonical units K: > > >> `sea_water_temperature_at_sea_floor` > > >> > > >> Here is a possible definition basically modifying the above to > remove the “potential” parts: > > >> > > >> Sea water temperature is the in situ temperature of the sea > water. The temperature at the sea floor is that adjacent to the ocean > bottom, which would be the deepest grid cell in an ocean model. > > >> > > >> There should probably also be a modification of the existing > sea_water_temperature definition to include this new name if it is > accepted: > > >> > > >> The sentence: > > >> "There are standard names for sea_surface_temperature, > sea_surface_skin_temperature, sea_surface_subskin_temperature and > sea_surface_foundation_temperature which can be used to describe data > located at the specified surfaces.” > > >> > > >> Should be changed to: > > >> > > >> "There are standard names for sea_surface_temperature, > sea_surface_skin_temperature, sea_surface_subskin_temperature, > sea_surface_foundation_temperature, and > sea_water_temperature_at_sea_floor which can be used to describe data > located at the specified surfaces.” > > >> > > >> -Barna > > >> > > >>> On 2019-09-09, at 11:23, Cathy Smith <[email protected]> wrote: > > >>> > > >>> All > > >>> > > >>> I have a new variable request; bottom temperature. It is the > temperature of the ocean floor (or the last level of a multi level > ocean dataset). I searched and was unable to find it or a variable > with "bottom" or synomyn as a level. I welcome being pointed out where > I missed it. > > >>> > > >>> It is an important variable for fish and aquatic populations > near coasts (or very shallow oceans). > > >>> > > >>> http://glossary.ametsoc.org/wiki/Bottom_temperature > > >>> > > >>> https://www.frontiersin.org/articles/10.3389/fmars.2019.00030/full > > >>> > > -- ******************************************************* * Nan Galbraith Information Systems Specialist * * Upper Ocean Processes Group Mail Stop 29 * * Woods Hole Oceanographic Institution * * Woods Hole, MA 02543 (508) 289-2444 * ******************************************************* _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata This email and any attachments are intended solely for the use of the named recipients. 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