Hi everyone,
I’m planning to run an AMIP experiment with present-day control forcings using suite u-cz934. Therefore, I need to fix the greenhouse gases, aerosols, and ozone concentrations to the levels close to recent climatology.
I compared this AMIP suite with a PI-control suite u-cy339 and found some possible approaches to fix these external forcing sources. However, I’m not sure whether my ideas are correct, so I would appreciate it if anyone could help me check the following steps in Rose GUI (The screenshots below all show the original settings of AMIP suite u-cz934).
1. Greenhouse gases
Rose edit: um -> namelist -> UM Science Settings -> Section 01-02-Radiation -> Gas MMRs (see screenshot below)
Turn off l_clmchfcg in the Varying gas MMRS option;
Replace the values of the greenhouse gas mixing ratios with values close to recent climatology.
2. Aerosols
Rose edit: um -> namelist -> UM Science Settings -> Section 34-UKCA: UK Aerosols and Chemistry (see screenshot below)
Replace the files in the ukca_em_files option with the pre-prepared climatological emission files available under /g/data/access on Gadi:
/g/data/access/TIDS/CMIP6_ANCIL/data/ancils/n96e/clim_1985-2014/AerosolChemistryEmissions
3. Ozone
Rose edit: um -> namelist -> Reconfiguration and Ancillary Control -> Configure ancils and initialise dump fields (see screenshot below)
Replace the ozone ancillary file with the pre-prepared climatological ozone file available on Gadi:
/g/data/access/TIDS/CMIP6_ANCIL/data/ancils/n96e/clim_1985-2014/OzoneConc
Additionally, there is an option INITIAL_OZONE in suite.conf -> jinja2 (see screenshot below). Should the file path in this option be replaced as well? Also, is it necessary to keep the REDISTRIBUTE_OZONE option set to true? This option controls the execution of the extra redistribute_ozone and retrieve_ozone routines which are absent in the PI-control suite u-cy339.
This is what I’m thinking, but I’m not quite certain. Are these the correct ways to fix these external forcings? Are there any other settings or steps I should modify to ensure the model to run as expected?
Any advice would be greatly appreciated. Thank you very much in advance!
Hao Wang