Modifying F compset for RCP8.5 conditions in CESM1

[sstevenson@ucsb_edu]

Hi there,

I'm trying to build an F compset case using the isotope-enabled version of CESM1, but to use fixed 2100 conditions appropriate for RCP8.5. A compset for this doesn't appear to exist, so I thought I would use an existing F compset and manually modify the namelist variables to be appropriate for RCP8.5 end-of-century. I also need to use CAM5 physics and CN BGC, to make the run consistent with the CESM1 Last Millennium Ensemble.

What I'm confused about is which compset would be the best starting point: I see that there is an F_AMIP_CAM5_CN compset and an F_1850-2000_CAM5_CN option on the list of supported compsets at

https://www2.cesm.ucar.edu/models/cesm1.2/cesm/doc/modelnl/compsets.html

Can someone please advise on the differences between these two and which one might be more suitable for modifying in this way? Or maybe it doesn't matter for this purpose?

Thanks!

 

[erik]

I'm moving this to the CAM forum, as it's probably better served there, since you are asking about F compsets.
But, to start a general answers. For the different open up the longer description for those compsets in the html you should above. The difference is going to be the period. AMIP is 1979 to present, and 1850-2000 is for that period. The precise definition is going to be seen in the cime_config/config_component.xml files for the subcomponents. So for example look at components/cam/cime_config/config_component.xml.

Also note there is this B compset:

RCP8_CAM5_CLM40%CN_CICE_POP2_RTM_SGLC_SWAV

And that's closer to the compset you should emulate. I recommend adding the F compset you want to the CAM config_component.xml file and base it on above, so a long name of something like...

RCP8_CAM5_CLM40%CN_CICE%PRES_DOCN%DOM_RTM_SGLC_SWAV

You could modify a case based on the two existing compsets you talk about above, but you'll need to modify a bunch of settings, so setting up the compset you want will be easier.

 

[sstevenson@ucsb_edu]

I think the version of CESM1 I'm using might be older than CIME - I don't see the components/cam/cime_config etc directory structure in my source code. It's located at /glade/u/home/samantha/iCESM1.2.0/tags/iCESM1_2_0_1_geotrace_n02 if that's helpful!

Do you know how one would go about doing the equivalent to what you mentioned in a pre-CIME source code setup? Sorry if this is a dumb question, I'm just having trouble locating the equivalent files!