On using "convert_units" preprocessor, units in configuration file not changed

[bettina-gier]

when using the convert_units preprocessor, the units in both the "metadata.yml", as well as "var_info.ncl" are kept as the cmor units, while the data fed to the diagnostics has different units. I feel like the updated units due to the preprocessor should be reflected, especially as I wanted to used the units attribute from these file for my plots, and I feel this may be a common occurence?

[nielsdrost]

Perhaps @jvegasbsc knows? :-)

[jvegreg]

Good catch! I am not sure how to proceed: the correct units are on the file, the var_info contains the original info. I think we should not change that info during the preprocessor, but I am not really sure. The safest way will be to read the units attribute from the NetCDF file and use this.

By the way, you opened Pandora's box here, as we are not taking this into account in any preproc function, and even some of them don't produce the correct units. A couple of examples:

• We are not changing them from mm day-1 to mm yr-1 when doing a yearly sum on pr
• We are not changing them from whatever m-2 to whatever when doing area sums

[bettina-gier]

Right, I'll use the units from the file then. Ideally I suppose you would have an "original units" attribute for the cmor info and then a "preproc units" for anything that the preprocessor did to it, though I can see how that might be hard to do. In this case at least the netcdf file has the correct attributes, while I guess the sums you mentioned above do not.

[bouweandela]

The original issue, as reported by @bettina-gier is a duplicate of #505. The issues reported by @jvegasbsc should probably be made into new issues.

[znicholls]

• We are not changing them from whatever m-2 to whatever when doing area sums

Made a specific issue for this here: #1613