Separate input file needed for fixed fields?

[emaroon]

What problem will this feature solve?
CESM output in time series format includes all fixed grid variables in each file in addition to the primary variable. Is it possible to read in one of the grid variables from that file in addition to the primary variable? Or do I need to create a separate file with the static field?

I've pushed my current setup for the natl_ocean POD to this branch in case it is helpful. For this POD at the moment, I need to read in 4 time-varying fields and TAREA (area of the cell). TAREA is available as an additional field in all 4 of the files for the time-varying fields. In that branch, I've added files to the NCAR_fieldlist to make this POD work, but suspect that there will be modifications needed: https://github.com/emaroon/MDTF-diagnostics/tree/allfiles

Describe the solution you'd like
It would be nice to be able to read in multiple variables from one file. Is there a way to do that that I haven't figured out yet?

Describe alternatives you've considered
Creating a separate file for fixed fields would be a solution, but it would require preprocessing before the preprocessing step, which makes the framework a little less convenient to use.

Additional context
This topic is also related to another open issue on fixed fields:
#316 (comment)

Let me know if what I'm describing doesn't make sense!

[wrongkindofdoctor]

@emaroon The next framework version will include the option to read multiple variables from one file using the the data catalog following the examples provided in the intake-esm documentation.

[emaroon]

Cool, thanks! For now I will use a separate file for TAREA and then when the next framework version is ready, switch to that.