How are emissions/concentrations treated in SSP scenarios?

[UllaH]

Dear forum!

I notice that one the scientifically validated experiments there is one for CESM2:

b.e21.BSSP585_BPRPcmip6.f09_g17.CMIP6-esm-ssp585.001

and one for CESM2-WACCM:

b.e21.BWSSP585cmip6.f09_g17.CMIP6-SSP5-8.5-WACCM.001

That makes me wonder: are GHG concentrations prescribed or calculated in a standard ssp scenario that one finds in the CMIP6 archive?

If prescribed, is there a configuration to run SSP585 with CESM2 this way? (I believe ESM means that it is calculated by the model).

Essentially I'm trying to set up a model run similar to SSP585 with CESM2.

Thanks in advance,
Ulla

 

[strandwg]

Dear forum!

I notice that one the scientifically validated experiments there is one for CESM2:

b.e21.BSSP585_BPRPcmip6.f09_g17.CMIP6-esm-ssp585.001

and one for CESM2-WACCM:

b.e21.BWSSP585cmip6.f09_g17.CMIP6-SSP5-8.5-WACCM.001

That makes me wonder: are GHG concentrations prescribed or calculated in a standard ssp scenario that one finds in the CMIP6 archive?

If prescribed, is there a configuration to run SSP585 with CESM2 this way? (I believe ESM means that it is calculated by the model).

Essentially I'm trying to set up a model run similar to SSP585 with CESM2.

Thanks in advance,
Ulla

The "esm" part of a CMIP6 experiment name denotes an emissions-driven experiment, and there is are some emissions-driven SSP5.85 experiments defined in CMIP6 (esm-ssp534-over esm-ssp585 esm-ssp585-ocn-alk esm-ssp585-ocn-alk-stop esm-ssp585-ssp126Lu esm-ssp585-ssp126Lu-ext esm-ssp585ext) but none have been run with CESM2.

All SSP data from CESM in the CMIP6 archive are concentration-driven.

 

[UllaH]

Thank you - and I assume that goes for every model participating unless the experiment has esm in it's name?

Ulla

 

[strandwg]

Thank you - and I assume that goes for every model participating unless the experiment has esm in it's name?

Ulla

That's correct.

 

[UllaH]

Thanks for clarifying.

Another related question regarding running CESM2. If I want to run in ESM setting (i.e. CO2 concentrations calculated, not prescribed) - which settings do I use?

I have the following compset: BSSP585
SSP585_CAM60_CLM50%BGC-CROP_CICE_POP2%ECO%ABIO-DIC_MOSART_CISM2%NOEVOLVE_WW3_BGC%BDRD

and in env_run.xml, the following settings:
CCSM_BGC=CO2C
CLM-CO2_type=diagnostic
OCEAN_CO2_type=diagnostic


Would this give me an SSP585-ESM run? Or would there be additional changes required?

Ulla

 

[strandwg]

Thanks for clarifying.

Another related question regarding running CESM2. If I want to run in ESM setting (i.e. CO2 concentrations calculated, not prescribed) - which settings do I use?

I have the following compset: BSSP585
SSP585_CAM60_CLM50%BGC-CROP_CICE_POP2%ECO%ABIO-DIC_MOSART_CISM2%NOEVOLVE_WW3_BGC%BDRD

and in env_run.xml, the following settings:
CCSM_BGC=CO2C
CLM-CO2_type=diagnostic
OCEAN_CO2_type=diagnostic


Would this give me an SSP585-ESM run? Or would there be additional changes required?

Ulla

I'm not the right person to answer that - you may want to start a new thread with that question.

 

[erik]

I'm pretty sure if the compset ends with BPRP it'll be the prognostic version rather than the diagnostic version which I think is what you are asking.

So...

SSP585_CAM60_CLM50%BGC-CROP_CICE_POP2%ECO%ABIO-DIC_MOSART_CISM2%NOEVOLVE_WW3_BGC%BPRP

If you look up the b.e21.BSSP585_BPRPcmip6.f09_g17.CMIP6-esm-ssp585.001 case in

CESM2 Experiments, Data & Diagnostic Output

Multi-decadal model runs of given component sets at the target resolution, followed by scientific review of the model output diagnostics

csegweb.cgd.ucar.edu

The compset used is pretty much above with CMIP6 settings turned on for CMIP6 history output.