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CESM2.1.3 for LGM

Dear all, I have done LGM simulations using cesm1. I was wondering, is it possible to do it with CESM2.1.3?
For instance, do we need new river runoff data for LGM?
I see there is no LGM output for LGM in CMIP6 data pool, only 127k simulation is available.

Thanks very much


New Member
CESM2 LGM simulation is being set up by the Paleoclimate Working Group and other groups. There is not ETA for when it can be used for scientific applications, as it is a difficult simulation to set up.


Nicolas Cosentino
New Member
Hi all,
I would like to ask if there have been any updates on this topic since the last response (August 2020). I have CESM2.1.3 installed at my university, and we would like to perform LGM experiments. However, as we learned in Zhu et al. (2021, Geophysical Research Letters), performing LGM experiments with CAM6 in CESM2 can lead to an unrealistically low global mean temperature decrease. Is it possible to run LGM experiments using CAM5 in CESM2.1.3?

Thanks in advance,


New Member
Hi Nico,

We are still working on an altered CESM2(CAM6) configuration for the LGM. This will take some more time, as we need to consider multiple lines of information, not just paleoclimate reconstructions.

Running CAM5 physics within CESM2 at the finite volume ~1° resolution is the validated configuration that produces an overall reasonable LGM simulation.
You can invoke the following change to build CAM5 within CESM2
./xmlchange CAM_CONFIG_OPTS="-phys cam5"


Willem Huiskamp
New Member
Dear all,
Is there information on what the paleo configuration of CESM2 will look like? What will the resolution of the model components be (for example, I've developed a ~3 degree MOM6 configuration, but I know many groups are now aiming for at least a 1 degree ocean)? I ask in part because my colleagues and I at PIK are considering moving to the CESM framework for paleoclimate modelling and were wondering what the status is of this new configuration.



New Member
Hi Willem,

Sorry for the late response.

We made some modifications to CAM6, which allowed the model to simulate a much more realistic LGM. This paleoclimate configuration is tested in 1.9×2.5° atmosphere and ~1° POP ocean. If you are interested in details, please check out my presentation at "2021 cesm workshop paleoclimate meeting". Let me know if you cannot find it on youtube.

It would be interesting to see how well CESM2 works with ~3° MOM6.

Happy to discuss this offline if you like.