Dear Christophe If wikipedia is correct, 1 Dobson unit equals 10 micrometres of the quantity equivalent_thickness_at_stp_of_atmosphere_ozone_content. The canonical unit is metres for this quantity in the standard name table, but any unit which is dimensionally equivalent to metres is acceptable. So it would be fine to specify units="10 micrometres" or units="10 um" (I think udunits accepts "u" for "micro"). This would be numerically equal to Dobson units.
The udunits table doesn't include Dobson units. We still have not provided a CF version of the table, as we have several times discussed doing. If we did, we could include a definition for dobson = 10 um. Best wishes Jonathan _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
