The landice/ismip6_run test group includes a test case for setting up one or more experiments from the ISMIP6 set of experiments. This functionality assumes the initial condition, parameter, and forcing files have already been generated using the ismip6_forcing test case. It creates a consistent set of run directories for the experiments requested. It is not meant for automated running of the experiments, and expert knowledge is recommended for conducting the actual experiments.

At present, there is a single test case for the ISMIP6-Projections2300-Antarctica ensemble.


landice/ismip6_run/ismip6_ais_proj2300 sets up one or more experiments from the protocol for ISMIP6-Projections2300-Antarctica.

The user should review and modify all values in the default config for specifying input files and model information. See config comments for detailed information about each option. Note that default filepaths refer to files at NERSC and may need to be updated depending on what machine is being used and user permissions. It may also be necessary to alter namelist, streams, or test case code if non-standard configurations are to be used.

config options

All config options should be reviewed and altered as needed. Example cfg files are included in the test case directory within the compass repo for previously used configurations on specific machines to facilitate reproducibility and form a useful starting place for new runs


# list of experiments to set up.
# Can be "tier1", "tier2", "all", or a comma-delimited list of runs
# "tier1" is expAE01-expAE06 plus hist and ctrlAE
# "tier2" is expAE07-expAE14
exp_list = tier1

# Resolution that will be set up, in km.  Should be one of 4, 8, as those are
# the two resolutions currently supported.
# mesh_res is informational only and is used for directory naming conventions
# The filepaths below must manually be set to be consistent.
mesh_res = 8

# number of tasks to use for each run
ntasks = 128

# value to use for config_pio_stride.
# Should be divisible into ntasks
pio_stride = 128

# Base path to the processed input ismip6 ocean and smb forcing files.
# User has to supply.
forcing_basepath = /global/cfs/cdirs/fanssie/MALI_projects/ISMIP6-2300/forcing/ais_mesh_8to30km_res

# Path to the initial condition file. User has to supply.
init_cond_path = /global/cfs/cdirs/fanssie/MALI_projects/ISMIP6-2300/initial_conditions/AIS_8to30km_20221027/relaxation_0TGmelt_10yr_muCap/

# Path to the file for the basal melt parametrization coefficients.
melt_params_path = /global/cfs/cdirs/fanssie/MALI_projects/ISMIP6-2300/initial_conditions/AIS_8to30km_20221027/

# Path to the region mask file
region_mask_path = /global/cfs/cdirs/fanssie/MALI_projects/ISMIP6-2300/initial_conditions/AIS_8to30km_20221027/

# Calving method to use.  Should be one of:
# 'restore' for restore-calving front method (fixed calving front)
# 'von_mises' for von Mises threshold stress calving law
calving_method = restore

# Path to the file containing the von Mises parameter fields
# groundedVonMisesThresholdStress and floatingVonMisesThresholdStress.
# Only required if calving_method is set to 'von_mises'
von_mises_parameter_path = UNKNOWN

# Whether facemelting should be included in the runs
include_face_melting = False

# True if running coupled MALI-sea level model simulation
sea_level_model = True

# NOTE: for the directories related to the sea-level model input/outputs, the slash '/' at the end of the directory name is necessary.
# Path to the base directory containing globally defined ice thickness field for the sea-level model
slm_input_ice = /global/cfs/cdirs/fanssie/MALI_projects/SeaLevelModel_Inputs/icemodel/

# Path to the directory containing earth model for the sea-level model
slm_input_earth = /global/cfs/cdirs/fanssie/MALI_projects/SeaLevelModel_Inputs/earthmodel/

# Earth structure profile
# possible values: any file name string of earth model file.
# Note that there is no single representative earth model for the globe or
# any region of the globe (e.g., West Antarctica, East Antarctica, Greenland)
# But for this test, we use 'prem_512.l60K2C.sum18p6.dum19p2.tz19p4.lm22' for West Antarctica
# and 'prem_coll_512.l120C.ump5.lm10' for East Antarctica. Other earthmodels that can be used
# should exist in the path defined in the config option 'slm_input_earth'.
slm_earth_structure = prem_512.l60K2C.sum18p6.dum19p2.tz19p4.lm22

# Path to the diectory containing other input files (present-day global topography and sea-level model grid files)
slm_input_others = /global/cfs/cdirs/fanssie/MALI_projects/SeaLevelModel_Inputs/others/

# number of gauss-legendre nodes in latitude (typically an integer multiple of 512)
nglv = 2048

Additionally, a user should also include the following options (and possibly others) that will be used for submitting the jobs for each ensemble member (set to appropriate values for their usage situation):

qos = regular

wall_time = 10:00:00

Steps for setting up and running experiments

  1. With a compass conda environment set up, run, e.g., compass setup -t landice/ismip6_run/ismip6_ais_proj2300 -w WORK_DIR_PATH -f USER.cfg where WORK_DIR_PATH is a location that can store the whole ensemble (typically a scratch drive) and USER.cfg is the user-defined config described in the previous section that includes options for [parallel] and [job], as well as any required modifications to the [ismip6_run_ais_2300] section. Likely, most or all attributes in the [ismip6_run_ais_2300] section need to be customized for a given application. It is possible to set up the test case without the -f option, but generally users will need to make their own adjustments to the example syntax above include it. Also, if you do not compile MALI in the MALI-Dev submodule within compass, you will need to include the -p option specifying the path to where you compiled MALI.

  2. After compass setup completes and all runs are set up, go to the WORK_DIR_PATH and change to the landice/ismip6_run/ismip6_ais_proj2300 subdirectory. From there you will see subdirectories for each experiment.

  3. Each experiment is to be run individually. Change to the subdirectory of the experiment you would like to run. It is suggested you review the job script, namelist, and streams files to be sure everything is set as expected. Then use sbatch to submit the job script.

Note that the hist run must be completed before any of the other experiments can be run. A symlink to the hist restart file from year 2015 exists in each of the other experiment subdirectories.

Important notes for running coupled MALI-SLM simulations

Projection handling

Currently, MALI uses a planar mesh that projects the south pole with polar stereographic projection of ellipsoidal Earth, and the sea-level model uses a global grid of spherical Earth. This inconsistency in the Earth’s assumed shape (ellipsoid vs. sphere) in MALI and the SLM causes discrepancies in the comparison of post-simulation ice mass calculations from the model outputs. To address this issue, an interim solution has been made to project the southern polar region onto the MALI planar mesh assuming a sphere (this is done by setting the lat/long in the MALI mesh using the ‘aid-bedmap2-sphere’ projection string in calling the function in ‘’. Thus, the resulting MALI mesh for coupled MALI-SLM simulations that are setup from this testgroup have the lat/long values based off sphere. Once the simulation outputs are generated, it is necessary to calculate and apply the scaling factors to the MALI outputs to correct for the areal distortion arose from projecting the south pole on a sphere onto plane. Only after applying the scaling factor, the MALI outputs will be comparable to the SLM outputs. The equations to calculate the scaling factors are shown in Eqn. 21-4 in An example of the calculation for the MALI-SLM case can also be found in the compass testgroup/testcase/ compass/landice/test/slm/circ_icesheet/, visualize step (

Mapping files

Coupling between the Sea-Level Model and MALI requires the generation of mapping files before simulations are run. When sea_level_model=True in the cfg file, an additional test case step is created named mapping_files. Before any MALI simulations are started, the user should run this step. It will generate the required mapping files, and they will be available in each experiment directory through symlinks. Once the mapping files have been generated, the user can proceed to running the hist experiment.


Additionally, for restarts with the SLM to work correctly, the entire history of the OUTPUT_SLM and ICELOAD_SLM directories must be present. Because the projection experiments (ctrl and exp*) are branched off the hist run as restarts, this means these two directories from the hist run must be manually copied to each projection run before beginning it. There is not an easy way for this to happen automatically, so this step must be done manually.