Hello Jonathan, The reason I'm resurrecting this discussion is that we came under strong pressure from a group of physical oceanographers to use 'dimensionless' with no scaling factor instead of PSU for salinity. I was raising the issue on the list to see how widespread this opinion was.
Cheers, Roy. -----Original Message----- From: cf-metadata-boun...@cgd.ucar.edu [mailto:cf-metadata-boun...@cgd.ucar.edu] On Behalf Of Jonathan Gregory Sent: 17 June 2009 08:06 To: cf-metadata@cgd.ucar.edu Subject: [CF-metadata] Salinity units Dear Roy and Alison The intention of recording the units as 1e-3 (dimensionless) was to suggest a canonical unit of PSU i.e. approximately the same as parts per thousand. However, this is unclear and therefore unsatisfactory. We have discussed this before, in fact, and I believe we have decided in principle that the unit should be indicated as psu. Since that is not a legal unit in the standard udunits.dat, in past discussions we have also decided we would publish our own CF version of udunits.dat, including psu as a unit (not convertible to other units). The CF udunits.dat should also include sverdrup (=1e6 m3 s-1) and bel B (hence decibel dB, dimensionless). The latter is already given as the canonical unit for some standard names, although it is not a legal udunit. I'd suggest that the CF udunits.dat, with these changes, should be put on our website, mentioned in 3.1 section about units in the CF standard, and used by the CF checker. Best wishes Jonathan _______________________________________________ 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