Hello everyone,
I’m working on the feedbacks of afforestation on the global carbon and water cycles during 1980–2100, using customized surface data and landuse timeseries data. To enable comparison with the CMIP6 model ensemble, I plan to use the BHIST_BPRPcmip6 and BSSP245cmip6 compsets. However, I’m confused about several details:
1. Choosing between BPRP and BDRD
From the documentation, I understand that BPRP and BDRD differ in how atmospheric CO₂ concentration is treated when calculating CO₂ surface fluxes—whether it is prescribed (constant) or interactively coupled between the atmosphere, land, and ocean. However, I’m not sure how to decide which one to use. My understanding is that BPRP would be more realistic when focusing on carbon uptake, yet some studies related to carbon sequestration still used BDRD, which confuses me.
2. Extending the historical period beyond 2014
I know that CMIP6 historical forcing data end in 2014, and CESM historical forcing is consistent with that. If I want to run BHIST up to 2022, is that feasible, or would it cause inconsistencies in the forcing setup?
3. Spin-up design
I carefully read the spin-up section in the user guide and reviewed related forum posts. Could you please let me know if my spin-up design below makes sense?
A. Spin-up (BHIST_BPRPcmip6)
Any clarification or advice would be greatly appreciated. Thank you very much for your time and help!
I’m working on the feedbacks of afforestation on the global carbon and water cycles during 1980–2100, using customized surface data and landuse timeseries data. To enable comparison with the CMIP6 model ensemble, I plan to use the BHIST_BPRPcmip6 and BSSP245cmip6 compsets. However, I’m confused about several details:
1. Choosing between BPRP and BDRD
From the documentation, I understand that BPRP and BDRD differ in how atmospheric CO₂ concentration is treated when calculating CO₂ surface fluxes—whether it is prescribed (constant) or interactively coupled between the atmosphere, land, and ocean. However, I’m not sure how to decide which one to use. My understanding is that BPRP would be more realistic when focusing on carbon uptake, yet some studies related to carbon sequestration still used BDRD, which confuses me.
2. Extending the historical period beyond 2014
I know that CMIP6 historical forcing data end in 2014, and CESM historical forcing is consistent with that. If I want to run BHIST up to 2022, is that feasible, or would it cause inconsistencies in the forcing setup?
3. Spin-up design
I carefully read the spin-up section in the user guide and reviewed related forum posts. Could you please let me know if my spin-up design below makes sense?
A. Spin-up (BHIST_BPRPcmip6)
- Use NCAR-provided initial files and default forcing.
- Hybrid run from 1900–1980.
- Save restart files.
- Use the restart files from (A).
- Modify surface data and landuse timeseries data.
- Hybrid run from 1981–2022.
- Save restart files.
- Use the restart files from (B).
- Modify surface data and landuse timeseries data again as needed.
- Hybrid run from 2023–2100.
Any clarification or advice would be greatly appreciated. Thank you very much for your time and help!