ACCESS-OM2: ACCESS Ocean-Ice Model Release Configurations

About the model

ACCESS-OM2 is a global coupled ocean - sea ice model developed by COSIMA.

ACCESS-OM2 consists of the MOM 5 ocean model, CICE 5 sea ice model, and a file-based atmosphere called YATM coupled together using OASIS3-MCT v2.0. ACCESS-OM2 builds on the ACCESS-OM (Bi et al., 2013) and AusCOM (Roberts et al., 2007; Bi and Marsland, 2010) models originally developed at CSIRO.

The model code, configurations and performance were described in Kiss et al. (2020), with further details in the draft ACCESS-OM2 technical report. The current code and configurations differ from this version in a number of ways (biogeochemistry, updated forcing, improvements and bug fixes), as described by Solodoch et al. (2022), Hayashida et al. (2023), Menviel et al. (2023) and Wang et al. (2023).

Support

ACCESS-NRI has assumed responsibility for supporting ACCESS-OM2 for the Australian Research Community. As part of this support ACCESS-NRI has developed a new build and deployment system for ACCESS-OM2 to align with plans for supporting a range of Earth System Models.

Any questions about ACCESS-NRI releases of ACCESS-OM2 should be done through the ACCESS-Hive Forum. See the ACCESS Help and Support topic for details on how to do this.

Build

ACCESS-NRI is using spack, a build from source package manager designed for use with high performance computing. This repository contains a spack environment definition file (spack.yaml) that defines all the essential components of the ACCESS-OM2 model, including exact versions.

Spack automatically builds all the components and their dependencies, producing model component executables. Spack already contains support for compiling thousands of common software packages. Spack packages for the components in ACCESS-OM2 are defined in the spack packages repository.

ACCESS-OM2 is built and deployed automatically to gadi on NCI (see below). However it is possible to use spack to compile the model using the spack.yaml environment file in this repository. To do so follow the instructions on the ACCESS Forum for configuring spack on gadi.

Then clone this repository and run the following commands on gadi:

bash spack env create access-om2 spack.yaml spack env activate access-om2 spack install

to create a spack environment called access-om2 and build all the ACCESS-OM2 components, the locations of which can be found using spack find --paths.

In contrast, the COSIMA ACCESS-OM2 repository uses submodules to bring all the code dependencies into a single repository and build all the models together.

Deployment

ACCESS-OM2 is deployed automatically when a new version of the spack.yaml file is committed to main or a dedicated backport/VERSION branch. All the ACCESS-OM2 components are built using spack on gadi and installed under the vk83 project in /g/data/vk83. It is necessary to be a member of vk83 project to use ACCESS-NRI deployments of ACCESS-OM2.

The deployment process also creates a GitHub release with the same tag. All releases are available under the Releases page. Each release has a changelog and meta-data with detailed information about the build and deployment, including:

• paths on gadi to all executables built in the deployment process (spack.location)
• a spack.lock file, which is a complete build provenance document, listing all the components that were built and their dependencies, versions, compiler version, build flags and build architecture
• the environment spack.yaml file used for deployment

Additionally the deployment creates environment modulefiles, the standard method for deploying software on gadi. To view available ACCESS-OM2 versions:

bash module use /g/data/vk83/apps/spack/0.20/release/modules/linux-rocky8-x86_64 module avail access-om2

For users of ACCESS-OM2 model configurations released by ACCESS-NRI the exact location of the ACCESS-OM2 model executables is not required. Model configurations will be updated with new model components when necessary.

For information on contributing your own fixes to the ACCESS-OM2 spack.yaml, see the Hive Docs article on creating a prerelease.

Conditions of use

COSIMA request that users of this or other ACCESS-OM2 model code:

1. consider citing Kiss et al. (2020) (http://doi.org/10.5194/gmd-13-401-2020)
2. include an acknowledgement such as that suggested here
3. let COSIMA know of any publications which use these models or data so they can add them to their list.