Setting up a coupled climate run for pre-industrial times

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. Note that many of the data files that are used to describe the boundary conditions can be found at

/ccc/work/cont003/dsm/p86ipsl/IGCM/INIT/ATM/LMDZOR/

Following, 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

Where for the BC run, an LMD experiment was copied, we now have to copy a LMDZOR experiment. We haven't tried whether LMDZ/clim BC files can be combined with LMDZOR/amip experiments but to keep it simple we propose to be consistent and thus combine LMDZ/amip BC files with an LMDZOR/amip experiment

cp ./EXPERIMENTS/LMDZOR/clim/config.card .

Edit the config card by changing the JOBNAME and setting the dates so that all dates of the experiment fall within the dates for which the BC were made.

../../util/ins_job 

This will create a new directory with the JOBNAME and copies the COMP, DRIVER and PARAM into that folder. Following the settings can be adjusted to the needs of the experiments

cd JOBNAME

LMDZOR can use both the 2-layer and 11-layer hydrology. ORCHIDEE-DOFOCO can only use the 11-layer hydrology so there is no choice but to use the 11-layers or CWRR scheme. First open the COMP/orchidee.card and change the suffix to ensure that the correct run.def will be used.

DefSuffix=CWRR

When installing LMDZOR we substituted the trunk version of ORCHIDEE by the DOFOCO-branch. The coupled set-up has some left overs of previous ORCHIDEE versions. Earlier the run.def of ORCHIDEE contained all settings because that was very difficult to read and maintain all parameters now get a default value and only when the default value needs to be changed, the parameter should be mentioned in the run.def. This basically resulted in an empty run.def when running a default set-up. LMDZOR still comes with unreadable full run.def which in the LMDZOR world is called PARAM/orchidee.def_CWRR. We propose to delete settings from the old run.def and only keep the following settings:

# When using the new physics (NP) use the corrected potential evapotranspiration. Not needed
# for the old physics (AP)
evapot_corr= CHOOSE{y/n} for {NP/AP}

# The river routing module does not like zoomed grids 
# because a zoom affects the coastal pixels. 
# Because in a zoomed grid, the coast may have moved 
# into the sea, some rivers are too short and 
# never make it to the ocean. The model notices 
# and will crash. 
RIVER_ROUTING = n 

# Use stomate (all the biogeochemical and anthropogenic processes)
STOMATE_OK_STOMATE = y

# To reset the time coming from SECHIBA restart file
# This option allows the model to override the time
# found in the restart file of SECHIBA with the time
# of the first call. That is the restart time of the GCM.
SECHIBA_reset_time = y

# Name of restart to READ for initial conditions
# This is the name of the file which will be opened
# to extract the initial values of all prognostic
# values of the model. This has to be a netCDF file.
# Not truly COADS compliant. NONE will mean that
# no restart file is to be expected.
SECHIBA_restart_in = _AUTO_

# Name of restart to READ for initial conditions of STOMATE
# If STOMATE_OK_STOMATE || STOMATE_WATCHOUT
# This is the name of the file which will be opened of STOMATE
# to extract the initial values of all prognostic values of STOMATE.
STOMATE_RESTART_FILEIN = _AUTO_

# Frequency in seconds at which to WRITE output
# This variables gives the frequency the output of
# the model should be written into the netCDF file.
# It does not affect the frequency at which the
# operations such as averaging are done.
WRITE_STEP = _AUTO_

# Frequency in seconds at which to WRITE output
# If SECHIBA_HISTFILE2
# This variables gives the frequency the output 2 of
# the model should be written into the netCDF file.
# It does not affect the frequency at which the
# operations such as averaging are done.
# That is IF the coding of the calls to histdef
#  are correct !
WRITE_STEP2 = _AUTO_

# STOMATE history time step (d)
# Time step of the STOMATE history file
# Care : this variable must be higher than DT_SLOW
STOMATE_HIST_DT = _AUTO_

# Interception reservoir coefficient.
# Transforms leaf area index into size of interception reservoir
#  for slowproc_derivvar or stomate.
SECHIBA_QSINT = 0.02
# default = 0.1

# If HYDROL_OK_HDIFF
# Defines how fast diffusion occurs horizontally between
#  the individual PFTs' water reservoirs. If infinite, no
#  diffusion.
HYDROL_TAU_HDIFF = 1800.
# default = 86400.

IF you are using ORCHIDEE-DOFOCO to its full potential, 13 PFTs - which is the default - is low. The two default DOFOCO set-ups have either 28 PFTs (without age classes) or 64 PFTs (with four age classes for each of the European tree species. This implies that you have to add all the PFT specific parameters as well. These parameters can be found in a table stored on /ccc/work/cont003/dofoco/dofoco/PARAMETERS/PARAMETER_VALUES/. The script Parameter_table_to_run_def0303.py at /ccc/work/cont003/dofoco/dofoco/SCRIPTS/rundef_from_table/ can be used to convert the table in run.def. The script allows a more or less flexible way of defining which PFTs need age classes. Have a look at the readme.txt file in the same folder.

Given that off-line ORCHIDEE runs were used to forward the land surface in time, the off-line runs may account for land cover change, forest management and litter raking. To increase the chances that an equilibrium climate is reached in under 20 years it is advised to switch off as many of these changes as possible.

READ_FM_MAP=y
LAND_COVER_CHANGE=n
VEGET_UPDATE=0Y
LIGNORE_LCC_STOPS=y
USE_LITTER_RAKING=y 

Land cover change is now switched off. Within the 20-year coupled run the land surface will stay constant to that described by the restart file that will be used, i.e., 1750. Forest management and litter raking are still activated (else we will affect the C-pools). We will keep these settings constant to their values for the year 1750. To do so change

I WILL FIRST TRY TO GET THIS WORKING WITHOUT A RESTART FILE

For the new physics set in COMP/lmdz.card

LMDZ_Physics=NPv3.1

For the old physics set in COMP/lmdz.card

LMDZ_Physics=AP

Set in PARAM/physiq.def_L39_NPv3.1

iflag_thermals=17
iflag_pbl=11

Make sure that stomate is on by looking in PARAM/orchidee.def_CWRR

STOMATE_OK_STOMATE = y

and in config.card (if this line is missing, there will be no STOMATE)

SBG= ("", "")

For the regular grid you are done and can try to launch the job:

ccc_msub Job_JOBNAME