Overview
The National Science Foundation funded Simple Ocean Data Assimilation (SODA) project provides retrospectively integrated, spatially complete reconstructions of the global historical ocean climate. The project goal is to provide a uniform, continuous picture of the evolving global ocean/sea ice system beginning January, 1980. The algorithm uses sparse physical oceanic/sea ice observations (including satellite SST, sea ice concentration, and in situ temperature and salinity profiles) as physical constraints to guide the evolution of a high-resolution numerical model. These constraints are applied via a modified version of the optimal interpolation data assimilation algorithm (derived based on minimizing a quadratic cost function).
The latest iteration, SODA4 (specifically the soda4.15 stream series), represents a step forward from the eddy-permitting architecture of SODA3. SODA4 introduces a global eddy-resolving 0.1° horizontal resolution and enhanced vertical resolution, for more accurate mapping of near-shore environments, shallow coastal processes, and narrow currents, and mixed layers where flow instabilities are important. For SODA4 we have also upgraded things such as the topographic map, ocean observations, and discharge data sets.
Dataset Metadata
| Data Type | Gridded mesoscale ocean/sea ice reanalysis variables (NetCDF-4 format) |
|---|---|
| Temporal Range | 45-year continuous timeline: 1980 – 2024 currently |
| Horizontal Resolution | 0.1° x 0.1° global grid (~10km at the equator; eddy-resolving) |
| Vertical Resolution | Enhanced vertical resolution ocean layers |
| Numeric Numerics | GFDL MOM5 Ocean Model / SIS1 Sea Ice Numerics |
| Surface Forcing | ECMWF ERA5 |
| Assimilation Method | Optimal Interpolation (OI) sequential analysis algorithm |
| Observational Constraints | Satellite SST, In situ T/S profiles (WOD/Argo), and Sea Ice Concentration properties |
Download Gateway & File Formats
Select your requested dataset configuration below. You can copy bulk download command strings directly into terminal contexts or fetch files via targeted mirrors.
Direct Data Server Mirror
Access directories containing raw NetCDF data catalogs, index schemas, and multi-version libraries directly via HTTP OPeNDAP storage pathways.
Go to Data Server5-Day Files
wget -r -l1 --no-parent --progress=bar -nd -A 'soda4.15.2_5dy_ocean_*.nc' https://dsrs.atmos.umd.edu/DATA/SODA4.15.2_OR/ocean/
wget -r -l1 --no-parent --progress=bar -nd -A 'soda4.15.2_5dy_ice_*.nc' https://dsrs.atmos.umd.edu/DATA/SODA4.15.2_OR/ice/
wget -r -l1 --no-parent --progress=bar -nd -A 'soda4.15.2_5dy_ocean_reg_*.nc' https://dsrs.atmos.umd.edu/DATA/SODA4.15.2_REG/ocean/
wget -r -l1 --no-parent --progress=bar -nd -A 'soda4.15.2_5dy_ice_reg_*.nc' https://dsrs.atmos.umd.edu/DATA/SODA4.15.2_REG/ice/
Monthly Files
wget -r -l1 --no-parent --progress=bar -nd -A 'soda4.15.2_mn_ocean_reg_*.nc' https://dsrs.atmos.umd.edu/DATA/SODA4.15.2_REG/ocean/
wget -r -l1 --no-parent --progress=bar -nd -A 'soda4.15.2_mn_ice_reg_*.nc' https://dsrs.atmos.umd.edu/DATA/SODA4.15.2_REG/ice/
Direct Granular Links (By Year Archive):
10-Day Files
wget -r -l1 --no-parent --progress=bar -nd -A.nc https://dsrs.atmos.umd.edu/DATA/soda4.15.2/SODA
wget -r -l1 --no-parent --progress=bar -nd -A.nc https://dsrs.atmos.umd.edu/DATA/SODA4.15.2_OR/transport
Citations & Contact
When using this dataset for publications, research, or process studies, please use the following primary scientific reference:
Chepurin, G. A., Carton, J. A., Sun, L., and Penny, S. G., 2025: SODA4: a mesoscale ocean/sea ice reanalysis 1980–2024, EGUsphere [preprint], DOI:10.5194/egusphere-2025-3810.
Contact and Inquiries
For feedback, questions regarding data availability, or to report problems in the reanalysis, please contact:
Dr. James A. Carton
Department of Atmospheric and Oceanic Science
University of Maryland, College Park, MD 20742
Email: carton@umd.edu