Introduce different tiers of model output, ideally standardized across components

[billsacks]

In discussions on managing CESM's output volume last year, there seemed to be general support for having multiple tiers of output – e.g., spinup/development/production; or default/high/extreme (I deliberately avoided "low/medium/high" because it gives the impression that "medium" should be the default, whereas I perceive that we want "low" to be the default). It sounds like some components already have infrastructure in place to support this, though I know that CTSM (for one) would need to allocate some development time to implement this.

It feels like the next step here is to form a small group that can come up with a CESM-wide plan. I feel this is an area where we really want consistency between the components in terms of the naming of the various tiers and what is the default.

(Within CIME, I could imagine implementing this similarly to other variables that have a value for each component, like NTASKS. So we'd have OUTPUT_ATM, OUTPUT_LND, etc. These could all default to something like "default", and then could be changed individually or for all components at once with an xmlchange command. It would be up to each individual component, however, to read the relevant xml variable and adjust its output accordingly.)

• For CTSM, see Different levels of "active" for history fields CTSM#528

[billsacks]

This doesn't seem to be high enough priority that it will happen anytime soon. I'm going to close it as a wontfix; we can always reopen it later if it becomes wanted.