New regional-mom6 release for setting up ACCESS-rOM3 domains
regional-mom6 is a python package that generates generic regional configurations for MOM6. Now it can also set up generic ACCESS-rOM3 domains, where ACCESS-rOM3 refers to regional configurations of ACCESS-OM3.
tl;dr
regional-mom6is a package that sets up generic regional MOM6 domains.- From version
1.0.4onwards, it can set up domains which run on ACCESS-OM3 executables. - It is deployed in a containerised environment to be easily loaded and used.
What’s new
regional-mom6 was released and published in 2024. At the time, MOM6 users were utilising the FMS coupler, and the package was originally built to support the FMS workflow. Since then, ACCESS-NRI was born, and have built ACCESS-OM3 using a NUOPC (rather than FMS) coupler.
As of version 1.0.4, regional-mom6 now has two options:
- Make a new domain ready to run ACCESS-rOM3 on Gadi
- Set up a FMS coupled run that is not machine specific
We expect that most Australian users will now be using option 1, but option 2 is still maintained for others, including those in Australia who are finishing existing work using an FMS coupled MOM6 instance.
In addition to now working with an ACCESS-NRI released executable, there are several other new features that have been introduced in the last year, particularly when it comes to grid generation options and flexibility. See the documentation for more information.
How to use it
To load the latest stable version into your environment run
module use /g/data/vk83/modules
module load rmom6
To use ACCESS-rOM3 you need to be a member of the vk83, ik11, qv56 and av17 NCI projects, and have a Copernicus Marine account.
or you can also load a specific release, e.g., module load rmom6/1.0.4_0.
This can be done in an ARE session by including /g/data/vk83/public/modules in “Module directories” and rmom6 in “Modules”.
The best place to get started is to download the demo and work through it. Go through once to construct and run the included “Tasmania” example, then have a go at modifying the notebook to construct a new domain. You don’t have to git clone the whole repository; you can download it to gadi via
wget https://github.com/COSIMA/regional-mom6/raw/refs/heads/main/demos/ACCESS-rOM3-demo.ipynb
then open it in your ARE session. It is highly recommended that you use git/github to version control both the model’s run directory and all of the code / notebooks that you use to generate your rOM3 domain. This can save you a lot of headaches and makes it much easier for others to help you troubleshoot.
While small domains like the demo will run within a few minutes on medium sized ARE sessions, larger domains (>1 million horizontal grid points) will require the largest ARE job size if not a dedicated PBS job with even more resources.
Disclaimer
This is not an official ACCESS-NRI release. Regional OM3 domains made with this workflow are not supported or maintained by ACCESS-NRI. As has always been the case with regional-mom6, the resulting domain is not necessarily science ready, or may not even run at all if boundary locations are chosen poorly (e.g., cutting through small bays). It is the responsibility of the user to validate and tweak the model as needed. For support, post an issue on the github page or ask for help on the ACCESS Hive forum.
However, this workflow is endorsed by ACCESS-NRI, and they provide support by maintaining a regional OM3 template for use with regional-mom6. This template is tested against ACCESS-OM3 releases to ensure that the workflow continues to function with the latest ACCESS-OM3 executables.
Limitations
As of 30/09/2026, the wave, sea ice and biogeochemistry components of ACCESS-OM3 (wavewatch, CICE and WOMBAT respectively) are not supported in this workflow.
Credits
@ashjbarnes and @manishvenu for regional-mom6 and mom6_forge changes
@dougiesquire and @helen for the ACCESS-OM3 template
@atteggiani and @jo-basevi for the deployment of the containerised environment
@ashjbarnes , @helen , @dougiesquire , @ellepola , @Lizzie and @cbull for testing