Hi Jonathan et al, This has reminded me of a CF units question that I was cogitating over a few weeks back.
In Section 3.3 of the CF conventions it states that: "Unless it is dimensionless, a variable with a standard_name attribute must have units which are physically equivalent (not necessarily identical) to the canonical units..." As a non-physicist, would someone care to explain what determines when a given pair of units are "physically equivalent", and when not. Some examples would be great! I can surmise that degrees K and degrees C are physically equivalent (simple offset). But what about K and degrees Fahrenheit? If these, say, are not physically equivalent then presumably you could not use the latter as the units for "air_temperature". Right? Regards, Phil On Tue, 2008-11-18 at 14:22 +0000, Jonathan Gregory wrote: > Dear Roy et al > > > Were you saying that um m-3 is dimensionally equivalent to kg m-3 or have I > > misunderstood? To me changing between these units changes the Standard Name. > > Yes, sorry. That was a mistake. I meant to say ug m-3 and kg m-3 are > dimensionally equivalent so equally acceptable. As you say, quantities with > dimensionally different units have different standard names. > > Cheers > > Jonathan > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
