AISLENS

AISLENS (The Antarctic Ice Sheet Large Ensemble) is a project to simulate a large ensemble of possible scenarios of future evolution of the Antarctic Ice Sheet under realistic variability in oceanic (and atmospheric?) processes. The purpose of this project is to understand the role of climate variability in the uncertainty of future sea level projections.

More details on the ensemble generator used in this work can be found in the aislens_emulation repository.[1]

The work makes use of the MALI (MPAS-Albany Land Ice)[2] model for running simulations and generating model outputs. This repository contains workflows necessary to generate the initial conditions and forcing files required for the same.

Dependencies

Project dependencies can be installed as a conda environment using the requirements.txt file:

git clone https://github.com/mshiv/AISLENS.git
cd AISLENS
conda create --name aislens-env --file requirements.txt

Important

The variability generator makes use of a forked version of the xeofs package, and details regarding changes made therein can be found at mshiv/xeofs-rand.

The project source code can be installed as a package if required:

conda activate aislens-env
pip install -e .

Data

Create a data/ directory in the root project repository, with the following structure:

/AISLENS/
├── data/
    ├── raw/
    ├── external/
    ├── interim/
    ├── processed/
    ├── tmp/

Copy the data files provided in the Zenodo object into this directory. The scripts/main.py script initializes and creates these directories based on the Path definitions provided in aislens/config.py, either in the root project repository, or in an alternative data location defined by DATA_ROOT (typically, the $SCRATCH working directory in a HPC machine.) This is best defined by the AISLENS_DATA_DIR environment variable, example below:

export AISLENS_DATA_DIR=$HOME/scratch/AISLENS

Workflow

The main scripts to generate initial conditions and forcing files to run the ice sheet model, MALI can be found in the src/ directory:

/AISLENS/
├── src/
    ├── aislens/    # project source code (Python)
    ├── MPAS-Tools/ # Custom scripts to regrid/viz. on the MALI mesh
    ├── scripts/    # main workflow scripts that utilize project source
    ├── R/          # R scripts for select data analyses & viz.

References

[1] S. Muruganandham, A. A. Robel, M. J. Hoffman and S. F. Price, "Statistical Generation of Ocean Forcing With Spatiotemporal Variability for Ice Sheet Models," in Computing in Science & Engineering, vol. 25, no. 3, pp. 30-41, May-June 2023, doi: 10.1109/MCSE.2023.3300908.

[2] Hoffman, M. J., Perego, M., Price, S. F., Lipscomb, W. H., Zhang, T., Jacobsen, D., Tezaur, I., Salinger, A. G., Tuminaro, R., and Bertagna, L.: MPAS-Albany Land Ice (MALI): a variable-resolution ice sheet model for Earth system modeling using Voronoi grids, Geosci. Model Dev., 11, 3747–3780, 2018, doi: 10.5194/gmd-11-3747-2018.

Further Information

GT Ice & Climate - AISLENS

Contact: smurugan9@gatech.edu / alex.robel@eas.gatech.edu