Oh sorry, Roy. I assumed one was without -35 and /1000 On Tue, Jul 18, 2017 at 7:06 PM, Lowry, Roy K. <[email protected]> wrote:
> Dear Balaji, > > > I think there are some crossed wires here. The dimensionless Practical > Salinity and a Practical Salinity in PSU are exact numeric equivalents. The > only difference is the name that's given to the unit of measure - that's > why to make this crystal clear CF includes the scaling factor of 10^-3. So > I don't think that this can affect storage precision. > > > Cheers, Roy. > > > Please note that I partially retired on 01/11/2015. I am now only working > 7.5 hours a week and can only guarantee e-mail response on Wednesdays, my > day in the office. All vocabulary queries should be sent to > [email protected]. Please also use this e-mail if your requirement is > urgent. > > > ------------------------------ > *From:* V. Balaji - NOAA Affiliate <[email protected]> > *Sent:* 18 July 2017 14:12 > *To:* Lowry, Roy K. > *Cc:* [email protected]; [email protected]; > [email protected]; [email protected] > *Subject:* Re: [CF-metadata] Is "psu" a valid cf unit? > > The ocean modeling community is adamant that they will continue to use > PSUs for salinity: it's this unit, rather than its SI or dimensionless > equivalent, that gives the maximum digits of precision in a floating-point > representation of salinity. > > It's a valid concern, and CF should perhaps reconsider, with a new > discussion giving weight to the views of modelers as well as physical > oceanographers. > > Thanks, > > Lowry, Roy K. writes: > > > Hello Martin, > > > > > > This topic has been debated at length in CF. To cut a long story short, > the term 'Practical Salinity Unit' was coined when the 1978 Practical > Salinity scale was devised. However, the term fell out of favour with the > physical oceanographic community whose current recommended practice is that > Practical Salinity - a ratio - should be a dimensionless number. CF > followed this recommendation and so PSU is not a part of CF. > > > > > > Have a dig around in the mailing list archive if you want to find out > more. > > > > > > Cheers, Roy. > > > > > > Please note that I partially retired on 01/11/2015. I am now only > working 7.5 hours a week and can only guarantee e-mail response on > Wednesdays, my day in the office. All vocabulary queries should be sent to > [email protected]. Please also use this e-mail if your requirement is > urgent. > > > > > > ________________________________ > > From: CF-metadata <[email protected]> on behalf of > [email protected] <[email protected]> > > Sent: 18 July 2017 13:43 > > To: [email protected]; [email protected]; > [email protected] > > Subject: [CF-metadata] Is "psu" a valid cf unit? > > > > Hello David, all, > > > > Is "psu" a valus CF unit? It is not in Udunits, but it is added in > cf-python as a unit alias and also appears to be accpeted by the > cf-checker. I can't see any mention of it in the CF Convention document: > the latter only lists level, layer, and sigma_level permitted departures > from Udunits, > > > > regards, > > Martin > > > > _______________________________________________ > > CF-metadata mailing list > > [email protected] > > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata > CF-metadata Info Page - University Corporation for ... > <http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata> > mailman.cgd.ucar.edu > This is an unmoderated list for discussions about interpretation, > clarification, and proposals for extensions or change to the CF conventions. > > > > CF-metadata Info Page - University Corporation for ...< > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata> > CF-metadata Info Page - University Corporation for ... > <http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata> > mailman.cgd.ucar.edu > This is an unmoderated list for discussions about interpretation, > clarification, and proposals for extensions or change to the CF conventions. > > > > mailman.cgd.ucar.edu > > This is an unmoderated list for discussions about interpretation, > clarification, and proposals for extensions or change to the CF conventions. > > > > > > > > ________________________________ > > 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. > > ________________________________ > > > > -- > V. Balaji Office: +1-609-452-6516 > <(609)%20452-6516> > Head, Modeling Systems Group, GFDL Mobile: +1-917-273-9824 > <(917)%20273-9824> > Princeton University Email: [email protected] > https://www.gfdl.noaa.gov/v-balaji-homepage > v-balaji-homepage – Geophysical Fluid Dynamics Laboratory > <https://www.gfdl.noaa.gov/v-balaji-homepage> > www.gfdl.noaa.gov > Bio Dr. V. Balaji is affiliated with Princeton University's Cooperative > Institute on Climate Sciences. He has headed the Modeling Systems Group at > NOAA's Geophysical ... > > > ------------------------------ > 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. > ------------------------------ > -- V. Balaji Office: +1-609-452-6516 Head, Modeling Systems Group, GFDL Mobile: +1-917-273-9824 Princeton University Email: [email protected]
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