FESOM restarts with a different time step

[mandresm]

Email from @a270067

just one more question. I wanted to change FESOM time step by continuing an experiment (i.e. run_number > 1). But got an error:

0: raw restart time 5097360.00000000 does not match current clock time 5097200.00000000
0: 1
srun: error: l20400: task 0: Exited with exit code 1

Is there any solution?

[mandresm]

Hi @a270067,

The way the fesom-2.0.yaml is configured is to write a clock.file where the previous date is calculated by subtracting the current time step to the current date:

esm_tools/configs/components/fesom/fesom-2.0.yaml

Line 305 in 279c277

lasttime: "$(( 86400 - ${time_step}))"

and:

esm_tools/configs/components/fesom/fesom-2.0.yaml

Lines 322 to 325 in 279c277

	create_config:
	fesom.clock:
	- "<--append-- ${lasttime} ${parent_date!sdoy} ${parent_date!syear}"
	- "<--append-- ${starttime} ${startday} ${start_date!syear}"

You could manually define in your runscript lasttime: "$(( 86400 - <length_of_previous_time_step> ))" but that would mean that for subsequent legs then you'll get a similar errors for the same reason. Therefore, I suggest you to use a switch (choose_) in your runscript so that this change only occurs for the first leg of your restarted simulation:

fesom:
    choose_general.run_number:
        <the_run_number_of_the_first_manual_restart>:
            lasttime: "$(( 86400 - <length_of_previous_time_step> ))"

Please, let me know if that does the job.

[a270067]

Thanks, it works.

[mandresm]

Happy to hear that!