CAM4/5 - aquaplanet & slab ocean?

[dkoll@uchicago_edu]

Is it possible to run CAM4 or CAM5 stand-alone in aquaplanet mode AND a slab ocean model (SOM)? As far as I can tell from the documentation, this option got disabled with CCSM4. However, I find this report (http://www.cesm.ucar.edu/management/CSL/2010/CESM11-12_SectionH.pdf) which states that somebody IS running CAM5 with aquaplanet and SOM:
"Aqua-planet experiments with perturbation sea-surface temperatures and slab-ocean model (SOM) experiments with perturbed CO2 values clearly show..."

 

[olson]

As far as I know, an aquaplanet SOM feature does not exist and is not supported. My reading of
your reference is of 2 separate research paths, one being an aquaplanet and the other being SOM. It
would take some modification of existing code to hook SOM into the aquaplanet framework.

 

[bitz@uw_edu]

I hacked CAM3 to run it's som as an aquaplanet (I call it somplanet). Let me know if you want it. The som in CAM3 was embedded directly in CAM, but now in 4/5, the som is it's own component. Thus the som in 4/5 allows us to run all the other components (except for the OGCM obviously). Primarily this means you get the whole sea ice model with the som in 4/5, while in 3 we only had a few bitz (pun intended) and pieces of the sea ice component slapped into cam3.

I think it would be necessary to turn off the sea ice dynamics in the cam4/5 som on an aquaplanet. The trouble is the sea ice dynamics were not designed to allow converging meridians. When you take out the land, this becomes a problem. This would be a fair bit of work. I'd be pleased to know if someone does it.

 

[eaton]

I also suspect this will be a big job. You could replace CICE with the stub sea ice component (sice), but that doesn't get around the fact that (I'm pretty sure) the DOCN component uses the POP displaced pole grid in it's SOM code. Which is fine until you remove the land and expose the pole singularities to the computational domain.

 

[rddixon@wisc_edu]

I hacked CAM3 to run it's som as an aquaplanet (I call it somplanet). Let me know if you want it.

I'd be interesting in seeing what you did with CAM3 to get the somplanet to run. I am going to try to always force SSTs above 60 degrees, so that I don't have to worry about ice, run a climatological aquaplanet with fixed SSTs in order to compute the Q-flux. Does this sound like an OK plan?

 

[bitz@uw_edu]

If you want this code, email me. You can find my email by googling my name Cecilia Bitz. I may just post the code on my web site if there is a stampede of interest.

 

[Riley]

Is it right that set som_planet =.true. in CAM3.1? But there is something wrong return:
READ_NAMELIST: Namelist read returns 19
ENDRUN: called without a message string
If I don't set it, it would run. It seems like CAM3.1 couldn't recognize "som_planet" ??