CESM1 questions: a) F compset with data land; b) perpetual F compset run with time varying SST forcing

[climatemodelling@gmx_com]

Dear Forum, I have two questions that someone hopefully has a solution to:a) Is there a simple way to switch of the land model within the F compsets? The supported compset list does not include any active atmosphere with data land option.b) From my undertanding, it is relatively easy to run a F compset in perpetual mode fixed to a certain date (via the namelist option). Is there a simple way to run CESM in perpetual mode (e.g. fixed incoming solar radiation to a certain date), however prescribe a time-varying SST boundary condition via the forcing file? Thanks!

 

[santos]

a) There is no way to run an active atmosphere without active land. CAM really depends on CLM to handle surface fluxes, so it's not so simple to come up with a reasonable data model that could replace CLM in any case.b) This can be done by changing the env_run.xml options starting with "SSTICE".

 

[eaton]

I'd be cautious about assuming perpetual mode works.  It's not a mode we test, and most of the interpolation code for boundary datasets has been changed since cam3 when I believe the perpetual mode was working.  So you need to check that all the forcings are doing what you expect in perpetual mode.  There are new namelist options for the interpolation of prescribed datasets that allow fixing the time that is being interpolated to.  To utilize this feature will require specifying namelist options in addition to just setting perpetual=.true. and perpetual_ymd to the desired date.

 

[santos]

Ah, I think there's some ambiguity here. I've heard some users use the word  "perpetual" to mean using the same year perpetually with climatological data sets (e.g. an F_2000 case). I actually didn't know about the "perpetual" namelist options that specify a perpetual day.Edit: Now that I re-read the original post, I can see that a perpetual date is what was meant. My mistake.

 

[climatemodelling@gmx_com]

There are new namelist options for the interpolation of prescribed datasets that allow fixing the time that is being interpolated to. Thank you for your feedback. Is there a list somewhere of the namelist options for perpetual runs within the CESM framework?

 

[eaton]

To my knowledge the perpetual mode is not an officially supported mode for the CESM model as a whole.  That means you'll need to look at the F compset components individually to determine whether they support a perpetual mode, and what namelist variables would be used to fix the date in the appropriate interpolations of boundary data. 

 

[kangwanying1992@gmail_com]

Have you found out a way to add step by step varying sst to perpetual winter model? Many thanks!Wanying