change CO2 concentration with F2000climo compset

[fahadabdullaah]

Hello,

I am running CESM 2.00 in Cheyenne. I ran a couple of prescribed SST runs with F2000climo. Now I want to change the CO2 concentration with F2000climo compset. I added co2vmr values in the user_nl_cam. However, the model doesn't take the value, and I don't see any changes in the atm_in, log, or in the output. I have also used ./xmlchange CCSM_CO2_PPMV=1138.8, which didn't solve the problem as well. However, if I change the compset to B1850, the model adds the CO2 value from the user_nl_cam.

My question is, how do I change CO2 concentration with the F2000climo compset?

Thanks,
Fahad

 

[eaton]

The F2000climo compset is using the use case file in cam/bld/namelist_files/use_cases/2000_cam6.xml. This file contains the settings that determine the GHGs, in this case

<flbc_file> 'atm/waccm/lb/LBC_2000climo_CMIP6_0p5degLat_c180227.nc' </flbc_file>
<flbc_list> 'CO2','CH4','N2O','CFC11eq','CFC12' </flbc_list>
<flbc_type> 'CYCLICAL' </flbc_type>
<flbc_cycle_yr> 2000 </flbc_cycle_yr>

These settings can be overridden in user_nl_cam, but to replace the flbc setting with a constant value like you get from setting co2vmr you'd need to remove the flbc settings (i.e., co2vmr doesn't override the flbc specification).

 

[fahadabdullaah]

The F2000climo compset is using the use case file in cam/bld/namelist_files/use_cases/2000_cam6.xml. This file contains the settings that determine the GHGs, in this case

<flbc_file> 'atm/waccm/lb/LBC_2000climo_CMIP6_0p5degLat_c180227.nc' </flbc_file>
<flbc_list> 'CO2','CH4','N2O','CFC11eq','CFC12' </flbc_list>
<flbc_type> 'CYCLICAL' </flbc_type>
<flbc_cycle_yr> 2000 </flbc_cycle_yr>

These settings can be overridden in user_nl_cam, but to replace the flbc setting with a constant value like you get from setting co2vmr you'd need to remove the flbc settings (i.e., co2vmr doesn't override the flbc specification).

Thank you!

 

[howard@earth_northwestern_edu]

Hello,

I am running CESM 2.00 in Cheyenne. I ran a couple of prescribed SST runs with F2000climo. Now I want to change the CO2 concentration with F2000climo compset. I added co2vmr values in the user_nl_cam. However, the model doesn't take the value, and I don't see any changes in the atm_in, log, or in the output. I have also used ./xmlchange CCSM_CO2_PPMV=1138.8, which didn't solve the problem as well. However, if I change the compset to B1850, the model adds the CO2 value from the user_nl_cam.

My question is, how do I change CO2 concentration with the F2000climo compset?

Thanks,
Fahad

Hi! I was wondering if setting the CO2 concentration can be done via ncdata as well? If I have specific an initial CO2 mixing ratio via ncdata, would that override/conflict with the specifications of the LBC file? Thanks for the help in advance!

 

[eaton]

ncdata is used to set initial conditions for prognostic variables, so would only impact a prognostic version of CO2 (e.g. in a WACCM compset). In the F2000 compset the CO2 which is radiatively active is a prescribed variable.

 

[howard@earth_northwestern_edu]

Thanks Dr. Eaton! So I'm guessing one wouldn't need to mess with co2vmr and the LBC file to specify prognostic CO2 concentrations (?)

 

[eaton]

The co2vmr namelist variable is only used to specify a constant value of CO2. The LBC files can be used with prescribed CO2 values in which case the values at the surface (the Lower Boundary Condition) are constant throughout the vertical column. The LBC files are also used with prognostic CO2 to specify the lower boundary values.

 

[howard@earth_northwestern_edu]

Ahh got it, thanks so much!!