Recommended Access Process for the DYAMOND Dataset on SciServer

See here for some details on the DYAMOND dataset (aka GEOS/ECCO C1440-LLC2160 Coupled Atmosphere-Ocean Simulation Dataset). The uncompressed dataset is about 2Pb and it can be opened on SciServer with xarray in about 3 seconds. From that point, making simple plots takes a few more seconds (see below for details on how to do this yourself).

Thanks to Oliver Jahn and Miguel Jimenez-Urias for creating the data on SciServer! They transferred the data from the NASA HPC cluster where it was originally computed and transformed the dataset for more performant user access.

Please send feedback to Thomas.Haine@jhu.edu and/or raise issues at the Poseidon-share Github repo.

To cite this dataset please use:

• Haine, T.W.N. 2025. Democratize the data: A new way to analyze and design ocean models. Oceanography 38(3), https://doi.org/10.5670/oceanog.2025.e303.

A good DYAMOND paper to cite is:

• Menemenlis, D., Molod, A., Hill, C.N. et al. The GEOS/ECCO C1440-LLC2160 Coupled Atmosphere-Ocean Simulation Dataset. Sci Data (2026). https://doi.org/10.1038/s41597-026-07349-2.

The DYAMOND ocean model uses the LLC2160 cubed sphere grid, which is described in this paper and this user guide. “LLC” stands for “latitude-longitude cap” and “2160” stands for 2160×2160 horizontal grid points in each of 13 faces that comprise the cubed sphere. The simulation spans 14 months starting on 20Jan20.

Access Instructions:

1. Create an account on SciServer and login to SciServer.
2. Request access to the Grendel_ceph_Oceanography group by sending Tom Haine an email with your SciServer login name (you’ll see an invitation in the Groups tab when it’s confirmed).
3. Click Compute.
4. Create a container using:
   • The Kraken domain,
   • The Oceanography Compute Image and,
   • The Poseidon ceph data volume.
5. Start the container by clicking on it in the Containers list.
6. Transfer the DYAMOND_access_demonstration.ipynb notebook to SciServer. This notebook opens the ocean variables in the DYAMOND dataset.
7. Run the notebook using the Oceanography kernel to test opening the DYAMOND dataset and making some simple plots.

Notes:

1. The data is stored in zarr v.2 format and is most easily accessed using xarray.
2. The actual full dataset lives in: “/home/idies/workspace/poseidon_ceph/DYAMOND”
3. Inside “DYAMOND” are the folders containing the zarr stores for all the DYAMOND data.

Coming soon:

1. DYAMOND data access using the OceanSpy API.
2. DYAMOND data access using the Seaduck API.
3. Full DYAMOND atmospheric dataset from the GEOS component of the coupled DYAMOND model.