CESM2 past1000 runs

[dstiller]

Hi,

I am interested in using the output of the CESM2 CMIP6 past1000 runs (cases b.e21.BWmaHIST.f19_g17.PMIP4-past1000.001/002), which I've found on GLADE. However, the output does not seem to have been post-processed (converted to timeseries, CMORized) or published to ESGF. Are there any issues with these runs one should be aware of?

Thanks,
Dominik

 

[strandwg]

Hi,

I am interested in using the output of the CESM2 CMIP6 past1000 runs (cases b.e21.BWmaHIST.f19_g17.PMIP4-past1000.001/002), which I've found on GLADE. However, the output does not seem to have been post-processed (converted to timeseries, CMORized) or published to ESGF. Are there any issues with these runs one should be aware of?

Thanks,
Dominik

These are available in timeseries format under

/glade/campaign/collections/cmip/CMIP6/timeseries-cmip6

 

[dstiller]

Thanks for pointing me to the output. So the fact that the output hasn't been published or isn't mentioned on the PWG website does not indicate any issues?

 

[strandwg]

Thanks for pointing me to the output. So the fact that the output hasn't been published or isn't mentioned on the PWG website does not indicate any issues?

I'm unaware of any issues. I'm not sure why they weren't CMORized.

 

[dstiller]

Perfect, thank you! Do you know if there is a historical run that was initialized from past1000 instead of piControl?

 

[strandwg]

Perfect, thank you! Do you know if there is a historical run that was initialized from past1000 instead of piControl?

There weren't any historicals started from the WACCM 2 deg past1000 runs.

 

[ducky8888]

Hi,

I am interested in using the output of the CESM2 CMIP6 past1000 runs (cases b.e21.BWmaHIST.f19_g17.PMIP4-past1000.001/002), which I've found on GLADE. However, the output does not seem to have been post-processed (converted to timeseries, CMORized) or published to ESGF. Are there any issues with these runs one should be aware of?

Thanks,
Dominik

Hi Dominik,

You're right those CESM2 past1000 runs (b.e21.BWmaHIST.f19_g17.PMIP4-past1000.001 and .002) are available on GLADE but haven't been CMORized or published to ESGF. To my knowledge, there's no critical issue with the simulations themselves, but since they haven’t been fully post-processed, you'll need to work with the raw monthly history files directly.

If you need the data in timeseries or CMOR format, you may need to process it manually using tools like ncl, cdo, or the CESM post-processing scripts, depending on what variables you're after.

It might also be worth reaching out to the CESM Paleo or PMIP team directly to check if there are plans to CMORize or publish these runs in the near future.

 

[strandwg]

The data from those runs can be transposed into timeseries format. Those runs will *not* be CMORized, as CMIP6 is frozen and no additional runs will be added.

 

[dstiller]

Thanks for your replies, I've found the time series on GLADE and am using those now.

Regarding issues, both ensemble members warm quite strongly (around 0.3 K/kyr), contrary to other simulations and proxy evidence. Jiang Zhu mentioned that this could be related to background stratospheric aerosols. In the spin-up/850CEcontrol run, some kind of climatology is prescribed. When the forcings are then switched to transient ones for the past1000 run, there is a radiative forcing from removing the climatological background aerosols.