Recommended Compset for Preindustrial and Industrial Historical Simulations

[namit7]

Hello guys:)

I am using CESM version 2.2. I want to do preindustrial and industrial era historical simulations of Community Atmopsheric Model from 1850 till present.

Could anyone tell which compset amongst active model should I preferred for accurate simulations considering the interactions between atmosphere, ocean, and land components? Also, I would like to know how to address bias and uncertainties within the model for accurate simulations

I would appreciate your contributions.

Regards,
Namit

 

[islas]

Hi Namit,

You can use the compset B1850 for the pre-industrial, and BHIST for the historical period. These are well vetted configurations. Biases do exist and you can read about these in the various papers in the CESM2 special issue https://agupubs.onlinelibrary.wiley.com/doi/toc/10.1002/(ISSN)1942-2466.CESM2, but this is the current state-of-the-art within CESM2. Note that we do already have pre-industrial and historical simulations available that you can look at through the CMIP6 archive and also through the CESM2 large ensemble project.

Best wishes,
Isla

 

[namit7]

Hi Namit,

You can use the compset B1850 for the pre-industrial, and BHIST for the historical period. These are well vetted configurations. Biases do exist and you can read about these in the various papers in the CESM2 special issue https://agupubs.onlinelibrary.wiley.com/doi/toc/10.1002/(ISSN)1942-2466.CESM2, but this is the current state-of-the-art within CESM2. Note that we do already have pre-industrial and historical simulations available that you can look at through the CMIP6 archive and also through the CESM2 large ensemble project.

Best wishes,
Isla

Hi Isla,

Thank you so much for your response. I am looking specifically to simulate the climate driven drought in the semi-arid region of India, historically and future using different RCP scenarios. Could you please inform which compset can run historically and future RCP scenarios. I believe I should use one compset for all the simulations so that my results are consistent.

I also think that having an active ocean component (MOM) is important for climate simulation to get the ocean feedback for SST.

Please let me know which compset would be the most suitable for my work.

Thank you,
Namit Choudhari

 

[islas]

Hi Namit,

To transition into the future you will have to start a new run initialized from the end of your historical run and use a different compset such as BSSP585, BSSP370, BSSP245, BSSP126, depending on the scenario you want to use. But if you want to look at simulations using these basic scenarios without doing anything different to the model, then you should be able to do so using data that we've already produced. You can look at the Climate Variability and Change Working Group Webpage to find information on simulations that are available for download. The CESM2 Large ensemble uses SSP3-7.0. We have a medium ensemble with the SSP2-4.5 scenario and we are in the process of running a medium ensemble with the SSP5-8.5 scenario. To keep up to date with the availability of the SSP5-8.5 ensemble you can join the working group mailing list mailman.cgd.ucar.edu Mailing Lists.

Isla

 

[namit7]

Hi Isla,

Thank you so much for the information. I plan now to run B1850 for historical simulation from 1850 to 1900 and BHIST from 1900 to 2020, and then will take the output from 2020 as input for the future scenario, e.g., BSSP585.

1. Just a quick question can we also use the B_1850-2000_BGC-BPRP (20TR_CAM4_CLM40%CN_CICE_POP2%ECO_RTM_SGLC_SWAV_BGC%BPRP) compset from one pre-industrial and historical? Or is that compset not tested yet?

2. Also, I read on an old (2021) CESM forum that the long name of BSSP585. Is: SSP585_CAM60_CLM50%BGC-CROP_CICE_POP2%ECO%ABIO-DIC_MOSART_CISM2%NOEVOLVE_WW3_BGC%BDRD, which uses diagnostic CO2 rather than prognostic CO2, and we need to change the last “BDRD” to “BPRP” to get a prognostic CO2 simulation. The new long name would be: SSP585_CAM60_CLM50%BGC-CROP_CICE_POP2%ECO%ABIO-DIC_MOSART_CISM2%NOEVOLVE_WW3_BGC%BPRP?
Is that still the case in CESM 2.1?

3. Also, are CH4 and N2O also interactive in BPRP?

4. And could you please tell how is SST varying in BSS858 and B1850, is it prescribed, or does it have some free calculation between steps?


I apologize for the many questions, but I would really appreciate your input.

Thank you,
Namit