[ferret_users] Ferret Doesn't Like units of "sigma_level"

[John Schattel <john.schattel@xxxxxxxx>]

Hello All,

The Ferret User's Guide says that Ferret supports COARDS netCDF files (see below).

As discussed in the Chapter, "Converting Data to NetCDF," (p. 247) Ferret expects netCDF files to adhere to the COARDS conventions (http://www.ferret.noaa.gov/noaa_coop/coop_cdf_profile.html).

And the COARDS profile says that "sigma_level" is an acceptable unit name (see below).

This standard also refers to version 1.7.1 of the udunits standard supported by Unidata. The udunits package is available via anonymous ftp at ftp.unidata.ucar.edu. Included in the udunits package is a file, udunits.dat, which lists collections of unit names. The names given therein and their plural forms will be regarded as acceptable unit names for this standard with the following additions and deletions:

• "degrees" - deleted
• "level", "layer", "sigma_level" - added

Yet when I run Ferret with a COARDS complaint netCDF file, it complains that it doesn't recognize "sigma_level" (see below).  Am I interpreting the diagnostic message correctly and if so should Ferret support units of "sigma_level"?

!  Define the dataset we will work with
use "http://localhost/cgi-bin/nph-dods/dgom/$1"
 !-> SET DAT/FORM=CDF "http://localhost/cgi-bin/nph-dods/dgom/hazmat.nc"
 *** NOTE: Units on axis "sigma" are not recognized: sigma_level
 *** NOTE: They will not be convertible:

Thanks for helping me understand what, if anything, needs to be done to address this issue.

John