CESM2 Fossil Fuel Emissions boundary conditions

[jbuzan@purdue_edu]

Hello CESM2 Staff,

I am attempting to locate the files that produce the total amount of carbon in CESM2 when the prognostic CO2 is on (e.g. B1850_BPRP) for historical runs and for SSP runs (e.g. BSSP370, BSSP245cmip6, etc.).

I want to manipulate the fossil fuel emissions to the total carbon released to the atmosphere. I tried looking in the
inputdata/atm/cam/chem/emis/
but these files appear to be aerosols, and not CO2 carbon.

How does CESM2 calculate the emissions of fossil fuels in the atmosphere?

Cheers,
-Jonathan

 

[jbuzan@purdue_edu]

::Update::

For the SSP scenarios, it looks like the file that controls atmospheric emissions is:
co2flux_fuel_file
For a specific example in SSP3:
inputdata/atm/cam/ggas/emissions-cmip6_CO2_anthro_surface_ScenarioMIP_IAMC-AIM-ssp370_201401-210112_fv_0.9x1.25_c20190207.nc

I also want to find the emissions file for B1850_BPRP, which is supposed to have prognostic CO2. But, I do not see a fuel emissions file, or something of the like. How does the B1850_BPRP compset set the co2 emissions?

 

[klindsay]

The surface emissions specified by co2flux_fuel_file are anthropogenic fossil fuel emissions. They are assumed to be zero in the 1850 configuration, so this namelist variable is not set in the B1850_BPRP compset. Additionally, this file is only read if co2_readflux_fuel=.true.. This nml variable is .false. by default, and is .true. in transient runs.

There are analogous anthropogenic CO2 emissions from aircraft that are specified via the variables in the aircraft_emit_nl namelist group.

BPRP compsets also include CO2 surface fluxes that are computed by the ocean and land components of CESM, fluxes that are passed to the atmosphere via the flux coupler. These fluxes are non-zero in all BPRP compsets, including B1850_BPRP. These fluxes are in CAM history files as SFCO2_OCN and SFCO2_LND respectively.

 

[jbuzan@purdue_edu]

Thanks Keith! This helps out a million!

Cheers,
-Jonathan

 

[jbuzan@purdue_edu]

Hi Keith,

I added:
> co2_readflux_fuel=.true.
to the user_nl_cam file, and built a new simulation, but when I check the cam.input_data_list in the Buildconf directory, I do not see a co2 file associated with fossil fuel emissions.

Is this a flag that is set in a different different file?

Cheers,
-Jonathan

 

[jbuzan@purdue_edu]

Hi Keith,

I added:
> co2_readflux_fuel=.true.
to the user_nl_cam file, and built a new simulation, but when I check the cam.input_data_list in the Buildconf directory, I do not see a co2 file associated with fossil fuel emissions.

Is this a flag that is set in a different different file?

Cheers,
-Jonathan

Hi Keith,

I think I realized the what the issue was. BHIST and B1850 are different compsets, and I need to be using BHIST for the 1850-2015 transient run.

Cheers,
-Jonathan