Model Experiments for PalMod II: AWI-ESM Phase Space Analysis

This project contains model source code, various run configurations, boundary conditions, and analysis software for examining the behaviour of AWI-ESM 2.1 during various times throughout the last glacial cycle. The goal of the project is to determine a phase space for several key climate indicators.

Getting a copy

The project can be downloaded via git. As some parts are within git submodules, particularly the climate model code and boundary conditions, the standard clone command needs to be extended:

git clone --depth 1 --recurse-submodules https://gitlab.awi.de/paleodyn/Projects/PalMod/phase-space-analysis.git

If you run into any problems, there are likely permissions errors. Please let Paul know and he will help to fix it.

Remember that you also will need to compile AWI-ESM 2.1 after downloading. To do that, you can run:

cd model_codes
esm_master comp-awiesm-2.1

Directory structure

• boundary_conditions: Contains various boundary conditions made with the standard boundary condition creation software. These correspond to the GLAC-1D 38ka BP, LGM, and 15ka BP reconstruction. Additionally, boundary conditions with "white blanket" ice sheets are provided.
• model_codes: Model binaries and source code
• experiment_run_configs: YAML files to be used with the esm-tools
• test_run_configs: YAML files to be used with the esm-tools, specifically for test_experiments
• preliminary_run_configs: YAML files to be used with the esm-tools, specifically for preliminary_experiments
• experiments: Experiments that can be usefully evaluated
• test_experiments: Experiments performed purely for technical testing purposes. No scientific value. Often, test runs will be used to get the actual YAML files to look correct.
• preliminary_experiments: Experiments performed so that scientifically useful ones can follow, e.g. stepwise adjustment to a new orogaphy.
• software: Helper software used for this project, e.g. the boundary condition creator.
• nonstandard_pool_files: Files that might be needed in FESOM, but are not in the standard Mistral pool.

Please note that everything, excluding the experiment directories, is checked into git version control here.

Included Boundary Conditions

Boundary conditions are hosted here. Currently, the following are included in this project:

• GLAC1D 15ka
• GLAC1D 15ka White Blanket
• GLAC1D 38ka
• GLAC1D 38ka White Blanket
• PISM 38ka
• GLAC1D LGM
• GLAC1D LGM White Blanket
• PISM LGM

If we need more, let Uta know so she can prepare them.

Setting up an experiment

All experiments are controlled via the esm-tools, version 5. The table below shows the current versions of each component:

Experiment run configurations are created in two or three phases. To avoid cluttering your main experiments folder with technical tests, use instead the test_experiments folder for short, 1 or 2 year test simulations to ensure the configuration you are using does what you want. Once that is the case, you can then begin the experiment and change out the base_dir setting under the general section of your yaml file.

A special case is needed when you change the orography and land-sea mask. Here, we must first perform a "bootstrap" simulation, which starts from a Pre-Industrial orography and iterates towards the desired orography over one simulation year. This must be done to avoid numerical instability, as directly starting the model with a new set of boundary conditions for the geopotential height (variable geosp) and the orography (and corresponding gravity-wave drag parameterization variables, OROMEA and friends) leads to a lookup table overflow and the model crashes. This is described in detail in the next section.

Orography Bootstrapping

To perform an orography bootstrap experiment, please set the following in your YAML file for the echam section:

echam:
    add_input_sources:
            jansurf: /work/ollie/pgierz/PalModII/boundary_conditions/finished_files/echam/T63CORE2_jan_surf_with_PI_GEOSP.nc
            target_orography: /work/ollie/pgierz/PalModII/boundary_conditions/finished_files/echam/T63CORE2_jan_surf_target_orog.nc
    add_input_files:
            target_orography: target_orography
    add_input_in_work:
            target_orography: target_orography_echam6.nc

    add_namelist_changes:
        namelist.echam:
            submodelctl:
                lupdate_orog: True

You may use the utility script utils/create_orography_bootstrap.py to set everything up. Please read that first.. The next table summarizes what variables should come from which file. The "Timeslice" file, is, for example, boundary_conditions/GLAC1D_15ka/echam/T63CORE2_jan_surf.nc

For the file listed under echam.add_input_sources.jansurf

For the file listed under echam.add_input_sources.target_orography, include only the variables for timeslice for GEOSP and ORO*:

• GEOSP
• OROGAM
• OROMEA
• OROPIC
• OROSIG
• OROSTD
• OROTHE
• OROVAL

You can use the script in utils/ to prepare that. If instead you would like to do it via CDO on your own, this may be a starting point (also in utils/mk_orog_bootstrap_files.sh):

PROJECT_ROOT=/work/ba0989/a270077/PalModII/phase_space_analysis
target_unit24=${PROJECT_ROOT}/boundary_conditions/GLAC1D_15ka/echam/T63CORE2_jan_surf.nc
pi_unit24=${PROJECT_ROOT}/nonstandard_pool_files/fesom/mesh_CORE2_finaltopo_mean/tarfilesT63/input/echam6/T63CORE2_jan_surf.nc
mkdir create_bootstrap_file
cd create_bootstrap_file
mkdir target_vars pi_vars merged
cdo splitname ${target_unit24} target_vars/target_
cdo splitname ${pi_unit24} pi_vars/pi_
rm target_vars/target_ORO*.nc
rm target_vars/target_GEOSP.nc
mv target_vars/* merged
mv pi_vars/pi_GEOSP.nc merged
mv pi_vars/pi_ORO*nc merged
cdo merge merged/*nc initial_unit24.nc
cdo splitname ${target_unit24} target_vars/target_
rm target_vars/target_ALAKE.nc
rm target_vars/target_ALB.nc
rm target_vars/target_AZ0.nc
rm target_vars/target_FAO.nc
rm target_vars/target_FOREST.nc
rm target_vars/target_GLAC.nc
rm target_vars/target_SLF.nc
rm target_vars/target_SLM.nc
rm target_vars/target_SN.nc
rm target_vars/target_WSMX.nc
rm target_vars/target_WS.nc
cdo merge target_vars/target_* target_uni24.nc

A bootstrapping experiment could be run as a "preliminary experiment", so as not to clutter your main experiment folder. If you want to run a test experiment first to ensure everything is technically correct, that's fine too...

Branching off from an existing experiment

To branch off from another run (or from the pre-orography bootstrapping run), you need to include the following in your YAML files:

echam:
    lresume: 1
    ini_parent_exp_id: Pre_LGM_orog_boot_022
    fake_initial_date: "2001-01-01"
    ini_parent_date: "$(( ${fake_initial_date} - ${echam.time_step}seconds ))"
    ini_parent_dir: "/work/ba0989/a270077/PalModII/phase_space_analysis/restart_files_from_ollie/Pre_LGM_orog_boot_022/restart/echam/"

fesom:
    lresume: 1
    ini_parent_exp_id: Pre_LGM_orog_boot_022
    ini_parent_dir: "/work/ba0989/a270077/PalModII/phase_space_analysis/restart_files_from_ollie/Pre_LGM_orog_boot_022/restart/fesom/"

Note that the JSBACH and HDMODEL components do not need explicit sections, they follow suite from ECHAM6.

Freshwater Forcing (Hosing) Experiments

... still to be written ...