Dear Maarten > >A mole is also a udunit, so mol m-3 and m-3 are different units, and > >quantities > >with those canonical units also have to have different standard_names. The > >standard_name indicates whether the quantity refers to number concentration > >or > >molar concentration. > > 1e15 molecules/cm2 NO2 is a valid column amount for NO2, but at the > same time I'm trying to convince my colleagues that this quantity > should be expressed in mol/m2 (specifically 16.6 micromol/m2 for > said column amount). These express the same quantity and should > _not_ use different standard names, not in the case of molecules. In > the end the number density should become extinct for molecular > species, switching completely to mol based units. Having different > standard names will only serve to hinder the transition.
Ah, I see (perhaps! :-) Is the point that "mole" means a particular number of molecules, so there should *not* be a distinction between [molecules] m-3 and mol m-3? Yes, that's a good argument, but in CF we are following SI, and mol is an SI unit, so a mole of NO2 is dimensionally different from 6e23 molecules of NO2. If it has a different unit, we have to give it a different standard name. udunits follows SI as well; you can't convert mol into a plain number. Best wishes and thanks for the explanation Jonathan _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
