Setting up a coupled climate run for pre-industrial conditions

The page follows the workflow of HowTo/CoupledDofoco and HowTo/SetupZoomEurope. For the commands and actions consult those pages. On this page the settings are specified.

The aim is to run an equilibrium simulation for the year 1750. Orchidee off-line line was used to simulate the surface area in 1750 and now we want to know how the climate looked liked for such a surface. The coupled run is zoomed over Europe, nudged at the edges of Europe uses the CWRR hydrology and all the DOFOCO features.

===THE BOUNDARY CONDITIONS=== LMDZOR was installed twice to avoid any confusion between the boundary files of the pre-industrial and the present day simulations. Hence, one installation will be used for the pre-industrial runs (and will thus use the pre-industrial boundary conditions), the other installation is to be used for present day simulations. For both sets of simulations an AMIP set-up was chosen. This set-up comes with acceptable BC between 1870 and 2100 which allows us to focus on the climate and reduce issues with sea surface temperature, see ice and aerosol concentrations. So copy the an amip config.card to define the job that will create the BC

cd config/LMDZOR_v5.2/
cp EXPERIMENTS/LMDZ/CREATE_amip/config.card ./

The following changes to were made to the config.card: (1) Add a suffix, i.e., -1750 to the job name so that the pre-industrial and present day boundary files will not interfere with each other

JobName= ELI-128x118x39-1750

(2) Set the begin date to the earliest year available. In this case we are limited by the SST and sea ice files to 1870. So we assume that the SST in 1870 represents pre-industrial conditions. Further we are planning 20 year long equilibrium simulations but we are not sure whether it will take 20 or 30 years so we simulate the BC for 30 years to be on the safe side.

DateBegin=1870-01-01
DateEnd=1899-12-31

There is no need to manually create a directory for this experiment. When you use ./util/ins_job the script will create a directory with a copy of the config.card as well as the COMP, DRIVER and PARAM folder. Next, some more settings need to be changed and/or confirmed before launching the job. The following changes to were made to the COMP/lmdz.card: (1) Specify in the list of parameter files that the BC should be based on the predefined pre-industrial settings. These settings contain the TOA solar incoming radiation, atmospheric CO2, CH4 and N2O among other settings. Have a loop in PARAM/config.def_preind to get a better idea of these settings.

(${SUBMIT_DIR}/PARAM/config.def_preind     ,  config.def),    \

(2) In the DRIVER/lmdz.driver it is specified that in the absence of the Oasis coupler, which is the case for LMDZOR, the ocean is forced. Hence the need of SST and sea ice files for all years in the experiment. (3) Most likely this is redundant at this stage but better safe than sorry so in PARAM/run.def set

VEGET=y

Now the ELI-128x118x39-1750 can be launched. It takes about 70 seconds per year so in this example it will take over 30 minutes to complete this 30-year job

ccc_msub Job_ELI-128x118x39-1750

THE PRE-INDUSTRIAL EXPERIMENT