AMIP configuration

Warning

  • Again, care must be taken when using the results of this model version (pre-release).

  • Only a limited number of compsets is presently working. Here, we show how to run a historical AMIP experiment on Betzy/Sigma2.

To create an experiment case follow instructions on NorESM webpage or, more specifically, for AMIP experiments follow instructions here. Below we show an example for only one specific compset, which has historical prescribed sea-surface-temperatures (SSTs) and historical forcing, typically 1979-2014 (or longer).

  1. First enter the scripts folder of the NorESM2.2 directory:

cd ~/<noresm-base>/cime/scripts/

  1. Then run command to create a new case, e.g., <case-name>:

./create_newcase --case ~/<noresm-base>/cases/<case-name> --mach betzy --res f09_f09_mg17 --compset NFHISTfsstfrc2 --project <project-name>

Here, we specify machine as “betzy”, a historical AMIP compset with frc2 forcing (generally recommended for NorESM), and the model will run with project resources <project-name>, typically of form “nn1234k” or similar. Note that different AMIP compsets can be found here:

vi <noresm-base>/components/cam/cime_config/config_compsets.xml.

  1. Enter the folder

cd ~/<noresm-base>/cases/<case-name>/

and specify the following in user namelist user_nl_cam (if file does not exist create it)

user_nl_cam

&chem_surfvals_nl

ch4vmr = -1.0D0

co2vmr = -1.0D0

f11vmr = -1.0D0

f12vmr = -1.0D0

flbc_file = ‘/cluster/shared/noresm/inputdata/atm/waccm/lb/LBC_1750-2015_CMIP6_GlobAnnAvg_c180926.nc’

flbc_list = ‘CO2’,’CH4’,’N2O’,’CFC11eq’,’CFC12’

flbc_type = ‘SERIAL’

n2ovmr = -1.0D0

scenario_ghg = ‘CHEM_LBC_FILE’

/

Note that the flbc_file path above is only relevant for “betzy” machine and can be set to another file if relevant. These variables (especially those set to “-1.0D0” should be specified to avoid an error where model is trying to run with both constant GHG/CFC gases and with time-evolving gases.

  1. Change other variables in user_nl_cam or other components’ namelists, set environment variables in files starting with “env_”, e.g., “env_run.xml” and setup, build and submit the model as shown on NorESM webpage.