Release

This is a Beta Release. Any model configuration and related source code mentioned in this page might change before the full release. Limited support is currently provided for this model. Its usage is only recommended for testing by experienced users and collaborators.

Run ACCESS-ISSM

1 About

ACCESS-ISSM integrates the Ice-sheet and Sea-level System Model (ISSM) to the ACCESS climate modelling framework, enabling fully parallel ice‑sheet simulations on the NCI Gadi supercomputer.

It is maintained and supported by ACCESS‑NRI.
A high‑level description of model components including the ISSM core, pre‑processing utilities and forcing data are available in the ACCESS-ISSM overview.

The example below reproduces the ISSM controbution to the third Marine Ice Sheet Model Intercomparison Project (MISMIP+) benchmark for ice flow models.

2 Prerequisites

Warning

To run ACCESS-ISSM, you need to be a member of a project with allocated Service Units (SU). For more information, check how to join relevant NCI projects.

NCI Account
Before running ACCESS-ISSM, you need to Set Up your NCI Account.
Join NCI projects
Join the following projects by requesting membership on their respective NCI project pages:
- vk83
- xp65

For more information on joining specific NCI projects, refer to How to connect to a project.

Modules

Load the following modules:

module load python3/3.9.2 #3.10.4
module load git

To run he model, a NCI project code with available compute allocation is required.

# 0. Choose a working directory for this test
$ mkdir -p ~/experiments/mismip && cd ~/experiments/mismip

# 1. Clone the ACCESS-ISSM repository (alpha branch)
$ git clone --branch development \
      https://github.com/ACCESS-NRI/access-issm.git

# 2. Load the ACCESS-ISSM module (vk83 deployment)
$ module use /g/data/vk83/modules
$ module load access-issm

# 3. Pre-process (mesh + inputs)
$ cp access-issm/test/run_pps.sh ./
$ qsub -P <NCI_PROJECT_CODE> run_pps.sh
# Alternatively use `bash run_pps.sh` inside a pInteractive job.
# Replace "<NCI_PROJECT_CODE>" with your active project code.

# 4. When PPS finishes, run the first experiment bundle
$ cp access-issm/examples/mismip/run_mismip_first.sh ./
$ qsub run_mismip_first.sh  # generates SSA vs ESTAR comparison plot

Outputs:

Mesh + forcing NetCDF/HDF5 → scratch/$PROJECT/$USER/mismip_pps/inputs/
ISSM state & plots → scratch/$PROJECT/$USER/mismip_run/Models_*/*

4 Running from ARE Desktop

ARE provides a GUI VDI plus a terminal already SSH‑tunnelled to gadi-login.

Launch VDI – open https://are.nci.org.au, choose Gadi Desktop (x64), click Launch.
Gadi Terminal – inside the desktop, open Gadi Remote Terminal.

Reserve nodes (optional but recommended):

persistent-sessions start issm
echo "issm.${USER}.au88.ps.gadi.nci.org.au" > \
     ~/.persistent-sessions/cylc-session

Load env + clone – as in Quick‑start (module …, git clone …).
Pre‑process & Run – submit the same run_pps.sh / run_mismip_first.sh with qsub.
Monitor – qstat -u $USER, or tail -f pps.o<jobid> in a terminal; use ARE’s Paraview for quick looks.
Release nodes when finished:
```
persistent-sessions stop issm
```

Tips

Heavy solves must run on the reserved nodes, not on the VDI itself.
VDI sessions expire after 12 h; jobs keep running.

5 File structure

experiments/mismip/
├── access-issm/                 # git clone (alpha branch)
│   └── examples/mismip/
│       ├── mismip_driver.py     # full driver script (all steps)
│       ├── run_pps.sh           # helper: submits PPS job
│       └── run_mismip_first.sh  # helper: submits early RUN job (steps 1‑7)
├── run_pps.sh                   # copied helper – edit walltime/resources here
└── run_mismip_first.sh          # copied helper – edit nodes/time as needed

6 Editing job scripts

Both helper scripts are standard PBS batch files. Typical tweaks:

Directive	Default	Change when…
`#PBS -P`	`au88`	Running under a different project code
`#PBS -l ncpus`	`32`	Mesh resolution < 1 km → reduce to 8–16 ; very high‑res → increase
`#PBS -l walltime`	`48:00:00`	Convergence problems: extend

For quick interactive debugging you can run the driver directly inside an ARE Desktop or qsub -I session:

$ python mismip_driver.py  # uses default steps list

ACCESS-ISSM configuration

Key configurable groups (edit the configuration files as needed):

Suite	Section	Purpose
PPS	Domain setup	Projection, bounds, resolution, MUA/SSA blend law, etc.
	Datasets	Surface mass balance, basal friction, geothermal heat, geometry DEMs
RUN	Time-stepping	`INITIAL_CYCLE_POINT`, `FINAL_CYCLE_POINT`, dt, adaptive settings
	Physics options	Flow law, calving, melting parameterisations
	Resources	MPI tasks, OpenMP threads, walltime

After editing configurations, simply re-run the corresponding suite’s script.

7 Troubleshooting

NaNs in solver residuals – try a smaller time‑step (dt) or increase the number of Picard iterations in the StressbalanceAnalysis.
PETSc convergence errors – confirm that md.stressbalance.reltol is properly set and not NaN; consider using hardware‑specific builds of PETSc ≥ 3.20.
Job submission hangs – check the log files for errors, verify that your module paths and environment variables (e.g., ISSM_DIR) are correctly set, and ensure proper resource allocation in your job scripts.

Get help

Ask questions in the ACCESS‑ISSM category on ACCESS‑Hive, or email support@access‑nri.org.au with your suite ID and a log excerpt.

- ISSM User Guide: https://issm.jpl.nasa.gov/documentation - ACCESS‑NRI ISSM build recipe: https://github.com/ACCESS-NRI/access-issm - NCI Cylc docs: https://opus.nci.org.au/display/DAE/Run+Cylc7+Suites