How the CO2 concentration is determined in CMIP6 amip-4xCO2

[kezhoulumelody]

Hi all,

I want to conduct a set of large ensemble that are similar to CMIP6 amip-4xCO2. However, I don't know how the CO2 concentration is set in amip-4xCO2 as the prescribed CO2 concentration is different every year. The compset I am using is FHIST_BGC, and I guess I am supposed to change the flgc_file where I quadruple the value of "CO2_LBC". The flgc_file = /glade/p/cesmdata/cseg/inputdata/atm/waccm/lb/LBC_1750-2015_CMIP6_GlobAnnAvg_c180926.nc

From what I have learned in the forum, I think I am supposed to create a new flbc_file and make the following changes in user_nl_cam

&chem_surfvals_nl
flbc_file = '/glade/xxx/my_directory/LBC_CMIP6_1pctCO2_y1-165_GlobAnnAvg_0p5degLat_c180929_4xCO2.nc'
flbc_list = 'CO2','CH4','N2O','CFC11eq','CFC12'
flbc_type = 'SERIAL'
scenario_ghg = 'CHEM_LBC_FILE'
/

There are other places setting the CO2 concentration like co2vmr, CCSM_CO2_PPMV, and co2flux_fuel_file. I don't know if I need to make any changes to these constants/files.

Thank you!

Best,

Melody

 

[peverley]

Moving this to the cam chem forum in the hopes that they have an answer for you!

 

[strandwg]

Hi all,

I want to conduct a set of large ensemble that are similar to CMIP6 amip-4xCO2. However, I don't know how the CO2 concentration is set in amip-4xCO2 as the prescribed CO2 concentration is different every year. The compset I am using is FHIST_BGC, and I guess I am supposed to change the flgc_file where I quadruple the value of "CO2_LBC". The flgc_file = /glade/p/cesmdata/cseg/inputdata/atm/waccm/lb/LBC_1750-2015_CMIP6_GlobAnnAvg_c180926.nc

From what I have learned in the forum, I think I am supposed to create a new flbc_file and make the following changes in user_nl_cam

&chem_surfvals_nl
flbc_file = '/glade/xxx/my_directory/LBC_CMIP6_1pctCO2_y1-165_GlobAnnAvg_0p5degLat_c180929_4xCO2.nc'
flbc_list = 'CO2','CH4','N2O','CFC11eq','CFC12'
flbc_type = 'SERIAL'
scenario_ghg = 'CHEM_LBC_FILE'
/

There are other places setting the CO2 concentration like co2vmr, CCSM_CO2_PPMV, and co2flux_fuel_file. I don't know if I need to make any changes to these constants/files.

Thank you!

Best,

Melody

I've attached the CASEROOT for f.e21.FHIST_BGC.f09_f09_mg17.CFMIP-amip-4xCO2.001; it may be of help to you.

 

[changmao]

I've attached the CASEROOT for f.e21.FHIST_BGC.f09_f09_mg17.CFMIP-amip-4xCO2.001; it may be of help to you.

Hi，I am learning how to use CESM FHIST for CO2 concentration increase experiments. I want to increase CO2 concentration to four times the pre-industrial level at the beginning of the simulation （4XCO2). But I really don't know how to modify Flbc_file. Should I directly change the CO2 value in the file to 4 times?

In the file you uploaded, flbc_file = /glade/work/brianpm/model_data/CFMIP/LBC_1750-2015_CMIP6_GlobAnnAvg_4xCO2_c190228.nc (cam_input_data_list), can I ask how to obtain or prepare this file.

Thanks a lot.

 

[strandwg]

Hi，I am learning how to use CESM FHIST for CO2 concentration increase experiments. I want to increase CO2 concentration to four times the pre-industrial level at the beginning of the simulation （4XCO2). But I really don't know how to modify Flbc_file. Should I directly change the CO2 value in the file to 4 times?

In the file you uploaded, flbc_file = /glade/work/brianpm/model_data/CFMIP/LBC_1750-2015_CMIP6_GlobAnnAvg_4xCO2_c190228.nc (cam_input_data_list), can I ask how to obtain or prepare this file.

Thanks a lot.

@brianpm, do you have this file handy?

 

[brianpm]

Sure. This file can be downloaded from here:

https://drive.google.com/file/d/1JU4U1fqnmdB9eJwglm_zWFCDPH8x2RP4/view?usp=sharing