Notebooks and Datasets for
Intrinsic oceanic decadal variability of upper-ocean heat content

A repository with Jupyter notebooks and datasets that reproduce the analyses and figures included in the paper:

Constantinou, N. C. and Hogg, A. McC. (2021) Intrinsic oceanic decadal variability of upper-ocean heat content. J. Climate. 34 (25), 6175-6189. doi:10.1175/JCLI-D-20-0962.1

@article{Constantinou-Hogg-2021,
  doi = {10.1175/JCLI-D-20-0962.1},
  year = {2021},
  volume = {34},
  number = {15},
  pages = {6175-6189},
  author = {Navid C. Constantinou and Andrew McC. Hogg},
  title = {Intrinsic oceanic decadal variability of upper-ocean heat content},
  journal = {J. Climate}
}

Contents

• prepare-raw-data.ipynb: Downloads raw data from various ACCESS-OM2 models and from CMEMS, manipulates the data (regrids, coarsens, monthly averages, 2D reductions), and produces smaller datasets saved in output directory.

• grids.zip: compressed .nc files with grid details for the ACCESS-OM2 models at three resolutions. Unzip before running notebooks.

• interpolation_weights.zip: compressed .nc files with the interpolation weights that xesmf package uses to regrid the ACCESS-OM2 model output and the CMEMS satellite altimetry onto a regular longitude-latitude grid with 1 degree lateral resolution. Unzip before running notebooks.

• output: Empty directory that is populated with output produced by prepare-raw-data.ipynb. Alternatively, if you don't have access to the raw the ACCESS-OM2 model output, you can dowload the processed output from the Zenodo repository at doi:10.5281/zenodo.4924968 and populate the output directory.

• process-data.ipynb: Process output from output directory to produce figures.

• figures: Figures produced by process-data.ipynb notebook.

ACCESS-OM2 model output

Some of the raw ACCESS-OM2 model output is available at doi:10.4225/41/5a2dc8543105a. However, accessing output from this doi requires users to have access the Australian National Computing Infrastructure (NCI).

Users with access to NCI's HPC systems should be able to download all model output used here given that they are members of projects cj50 and ik11. The experiments we use here are summarized in the table below.

Resolution	Forcing	Experiment name
1	IAF	1deg_jra55v13_iaf_spinup1_B1
1	RYF	1deg_jra55_ryf9091_gadi
0.25	IAF	025deg_jra55v13_iaf_gmredi6
0.25	RYF	025deg_jra55_ryf9091_gadi
0.10	IAF	01deg_jra55v140_iaf, 01deg_jra55v140_iaf_cycle2, 01deg_jra55v140_iaf_cycle3
0.10	RYF	01deg_jra55v13_ryf9091

(The IAF 0.10 degree outputs are also available via THREDDS at https://dapds00.nci.org.au/thredds/catalogs/cj50/access-om2/raw-output/access-om2-01/access-om2-01.html.)

Notebook prepare-raw-data.ipynb utilizes cosima-cookbook's functionality to load the required variables needed from the above-mentioned experiments, do some processing (e.g., slice and regridding) and then save them as .nc files in the output directory.

If getting access to the Australian National Computing Infrastructure seems cumbersome, then you can download the processed output from the Zenodo repository doi:10.5281/zenodo.4924968 and use this sliced/regridded data to populate the output directory and proceed with analysing it.

Directory structure

After you have unzipped all files and either have run prepare-raw-data.ipynb notebook or downloaded output from Zenodo repository at doi:10.5281/zenodo.4924968, the repository's directory structure should look like:

.
├── README.md
├── LICENSE
├── .gitinore
├── grids
│   ├── ocean_grid_10.nc
│   ├── ocean_grid_025.nc
│   └── ocean_grid_01.nc
├── interpolation_weights
│   ├── bilinear_tracer_weights_in025degcmems_out1deg.nc
│   ├── bilinear_tracer_weights_in1degACCESSOM2_out1deg.nc
│   ├── bilinear_tracer_weights_in025degACCESSOM2_out1deg.nc
│   └── bilinear_tracer_weights_in010degACCESSOM2_out1deg.nc
├── output
│   ├── README.md
│   ├── cmems-monthlymean-regridded
│   │   ├── ssh-XXXX.nc
│   │   └── ...
│   ├── ssh-1deg-RYF-regridded
│   │   ├── ssh-XXXX.nc
│   │   └── ...
│   ├── ...
│   ├── ssh-1deg-IAF-regridded
│   │   ├── ssh-XXXX.nc
│   │   └── ...
│   ├── ...
│   ├── uohc-1deg-0m-50m-RYF
│   │   ├── uohc-XXXX.nc
│   │   └── ...
│   ├── ...
│   └── uohc-1deg-0m-50m-IAF
│       ├── uohc-XXXX.nc
│       └── ...
├── figures
│   ├── figure1.pdf
│   └── ...
├── prepare-raw-data.ipynb
└── process-data.ipynb