Change atmospheric CO2 scalar value

For offline simulations, the scalar value for atmospheric CO2 can be set in run.def using ATM_CO2=x, default value is 350. For constant value, set directly in run.def your choice.

For a annual change in CO2, using OOL_SEC_STO and libIGCM, you can add a ascii file with annual values and the driver will update ATM_CO2. The file has to be with following syntax :

Annee_1990=352.00
Annee_1991=353.55
Annee_1992=355.09
Annee_1993=356.63
Annee_1994=358.16

The file must be added to the input files and it must be called CO2.txt. To do so, add in stomate.card section BoundaryFiles/ListNonDel :

[BoundaryFiles]
ListNonDel= (../../../yourfile_CO2.txt, CO2.txt)

You must set atmospheric ATM_CO2 in PARAM/run.def to (do not comment it out):

ATM_CO2 =  _AUTO_: DEFAULT = 350.

Files with CO2 values according to the CMIP5 and TRENDY2 protocole can be found at the shared repository. For exemple :

basedir/IGCM/BC/ATM/LMDZOR/IPCC_AR5/RCPs/RCP85/CO2_1765_2500.txt
basedir/IGCM/BC/ATM/LMDZOR/IPCC_AR5/HISTORIQUE/CO2_1765_2005.txt
basedir/IGCM/BC/SRF/OL2/CO2_1860_2012_TRENDY2.txt

where basedir

• at curie, basedir=/ccc/work/cont003/dsm/p86ipsl
• at ada, basedir=/workgpfs/rech/psl/rpsl035
• at obelix, basedir=/home/orchidee01/mmancip (only protocole TRENDY2 at obelix)

NB! Note that if the year you simulate is not in the file, run.def will contain an empty variable "ATM_CO2=" and the model will of course crash.