Will running multiple cycles under one workflow create output identical to many workflows with a singe cycle each?


I'm tasked with creating a training dataset by running 54-hour forecasts starting 24 hours apart through the summer months of many years. I have discovered I can use the SRW config.sh params DATE_FIRST_CYCL and DATE_LAST_CYCLE to run multiple cycles with one workflow. Will this create output identical to that from running a workflow for each day of my period of interest? I have been using this latter approach (one cycle and one workflow per day) and it's been causing resource problems with the cron host on cheyenne. So I am looking for an alternative.

For example, I want to run 54-hour forecasts for each day of July, 2022. I have a script that creates a config.sh for each of the 31 days in July and runs ./generate_FV3LAM_workflow from regional_workflow/ush. In each of these configs, DATE_FIRST_CYCL is the same as DATE_LAST_CYCLE, so the workflow runs one cycle. My question is whether I could accomplish exactly the same output with a single workflow configured with:


I see that when I use this multiple-cycle mechanism output is generated in a separate, dated, directory for each cycle under the expt_dir for my workflow. But does anyone have a sense if there is a functional difference between these two ways of running the model? Is initialization done differently, or anything else under the hood that I should be aware of?

Thank you in advance, and please let me know if you need more information about what I am trying to do,

-Paddy McCarthy

Hi Paddy,

There is no difference between what you've been doing and running a single workflow with multiple cycles.  However, the latter will be much easier for you to configure and manage, as you've already identified!  Everything from initialization to how the model runs will be identical, so long as your entries in the config.sh files don't change (other than DATE_FIRST/LAST_CYCL).

- Jeff

Thank you, Jeff! I'm looking forward to trying out this feature. I really appreciate the sanity check / confirmation.