Dear community,
I have set up an attribution framework with CESM2, and have two questions about my setup.
So far I have simulated two runs:
My factual simulation with historical emissions:
COMP=FHIST_BGC
./xmlchange CCSM_BGC=CO2A
A counterfactual simulation with historical land-use and pre-industrial co2 and aerosol forcing otherwise
COMP=FHIST_BGC
./xmlchange CAM_NML_USE_CASE=1850_cam6
./xmlchange CAM_NAMELIST_OPTS=co2_cycle_rad_passive=.true.
./xmlchange CCSM_BGC=CO2A
Q1: I have copied the co2_cycle_rad_passive=.true. from a different setup from this forum, but I don't fully understand its explanation.
Q2: I want to start a third simulation with the radiative effects of CO2 in the atmosphere, but no CO2 fertilization in CLM. The vegetation should see constant pre-industrial CO2 concentration. According to the description in env_run.xml I can set CLM_CO2_TYPE to "constant", which means that clm sees CCSM_CO2_PPMV. Would this work if "CCSM_CO2_PPMV" value="284.7" but the atmosphere still used transient co2 due to "CAM_NML_USE_CASE" value="hist_cam6"? Also, if CLM gets a constant 284.7, does it mean that CO2 is constant across all latitudes and seasons? Is there an alternative way to disable CO2 fertilization?
Thanks a lot for the help!
Cheers,
Istvan
I have set up an attribution framework with CESM2, and have two questions about my setup.
So far I have simulated two runs:
My factual simulation with historical emissions:
COMP=FHIST_BGC
./xmlchange CCSM_BGC=CO2A
A counterfactual simulation with historical land-use and pre-industrial co2 and aerosol forcing otherwise
COMP=FHIST_BGC
./xmlchange CAM_NML_USE_CASE=1850_cam6
./xmlchange CAM_NAMELIST_OPTS=co2_cycle_rad_passive=.true.
./xmlchange CCSM_BGC=CO2A
Q1: I have copied the co2_cycle_rad_passive=.true. from a different setup from this forum, but I don't fully understand its explanation.
Q2: I want to start a third simulation with the radiative effects of CO2 in the atmosphere, but no CO2 fertilization in CLM. The vegetation should see constant pre-industrial CO2 concentration. According to the description in env_run.xml I can set CLM_CO2_TYPE to "constant", which means that clm sees CCSM_CO2_PPMV. Would this work if "CCSM_CO2_PPMV" value="284.7" but the atmosphere still used transient co2 due to "CAM_NML_USE_CASE" value="hist_cam6"? Also, if CLM gets a constant 284.7, does it mean that CO2 is constant across all latitudes and seasons? Is there an alternative way to disable CO2 fertilization?
Thanks a lot for the help!
Cheers,
Istvan