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cf-convention / vocabularies

Issues and source files for CF controlled vocabularies
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mol/m3/uatm #208

Closed andyjacobson closed 3 months ago

andyjacobson commented 1 year ago

Howdy. I am forever telling collaborators that they should not write units like mol/m3/uatm, or g/m2/s and that they should instead write "mol m-3 uatm-1" or "mol/(m3 uatm)". However, I find it difficult to point to a place in the CF-spec that states this clearly. Is this written explicitly somewhere? Thanks!

davidhassell commented 1 year ago

Hello @andyjacobson,

All three of mol/m3/uatm, mol m-3 uatm-1 and mol/(m3 uatm) all allowed by the UDUNITS syntax, and all describe exactly the same units, i.e. 9.86923266716013 m-2.kg-1.s2.mol. So whilst I personally am also not so fond of the "x/y/z" formatting, I think it's perfectly legal, I'm afraid!

Thanks, David

andyjacobson commented 1 year ago

David, thanks for your comments. I'm baffled as to why x/y/z would be legal syntax. Isn't that mathematically equivalent to (xz)/y, as opposed to the intended x/(yz)? Anyway, I guess I should take up my question with the UDUNITS folks.

japamment commented 3 months ago

Closing this issue as the original question was answered.