SODA v3.3.1

Ocean data assimilation model

The goal of SODA is to reconstruct the historical physical (and eventually biogeochemical) history of the ocean. As its name implies, the Simple Ocean Data Assimilation ocean/sea ice reanalysis (SODA) uses a simple architecture based on community standard codes with resolution chosen to match available data and the scales of motion that are resolvable. Agreement with direct measurements (to within observational error estimates) as well as unbiased statistics are expected. While SODA remains a university-based research project, we want to be helpful. The goal is to provide a reliable source of seasonal climate time-scale ocean reanalysis to complement the atmospheric reanalyses available elsewhere (NOAA/EMC, NASA/GMAO, and ECMWF, for example).

SODA Version 3 represents a major change from the previous SODA2. It now uses GFDL MOM5/SIS numerics at finer 1/4°x1/4°x50lev (28km at the Equator down to <10km at polar latitudes) resolution, similar to the ocean component of the GFDL CM2.5 coupled climate model, and includes an active sea ice component. The Optimal Interpolation filter has also been augmented (relative to previous releases) with bias correction to reduce bias in estimates of long term trends of variables such as heat content.

SODA3.3.1, forced by MERRA2 and spanning the 36-year period 1980-2015 from the source website. They have also made available the 5-day and monthly fields remapped onto a uniform 1/2°x1/2° Mercator horizontal grid similar to SODA2, but with expanded vertical resolution along with variables on the native 1/4°x1/4°x50levx5dy tripolar grid and variables remapped onto an isopycnal grid.

Citing the data

When using the data set in a paper, please provide the SODA3 ensemble member (e.g. SODA3.3), the date/site the data were downloaded from, and cite the following reference:

Carton, J.A., G.A. Chepurin, and L. Chen, 2016: An updated reanalysis of ocean climate using the Simple Ocean Data Assimilation version 3 (SODA3), manuscript in preparation.


Jackett, D.R., T.J. McDougall, R. Feistel, D.G. Wright, S.M. Griffies, 2006: Algorithms for density, potential temperature, conservative temperature and the freezing temperature of seawater J. Atmos. Ocean. Technol., 23,1709-1728

monthly means / 5 day mean:
potential temperature [degc], salinity [psu], dia-surface velocity t-points [m/s], sea level [m],
mixed layer depth determined by temperature criteria [m],
depth of potential density mixed layer [m],
mixed layer depth determined by salinity criteria [m],
t-cell bottom pressure - rho0*grav*ht [dbar],
surface ocean heat flux coming through coupler and mass transfer [watts/m^2],
salt flux total [kg/(m^2*sec)], potential density referenced to 0 dbar [kg/m^3],
zonal velocity [m/s], meridional velocity [m/s],
i-directed wind stress forcing u-velocity [n/m^2],
j-directed wind stress forcing u-velocity [n/m^2]
monthly means isoypycn surfaces:
depth of isoypycn [m], potential temperature at the depth of isopycn [degc], salinity at the depth of isopycn [psu]
ZonalGlobal by 0.5 deg
MeridionalGlobal by 0.5 deg
monthly means / 5 day mean:
5.03355, 15.10065, 25.21935, 35.35845, 45.57635, 55.86325, 66.26175, 76.80285, 87.57695, 98.62325, 110.0962, 122.1067, 134.9086, 148.7466, 164.0538, 181.3125, 201.263, 224.7773, 253.0681, 287.5508, 330.0078, 382.3651, 446.7263, 524.9824, 618.7031, 728.6921, 854.9935, 996.7153, 1152.376, 1319.997, 1497.562, 1683.057, 1874.788, 2071.252, 2271.323, 2474.043, 2678.757, 2884.898, 3092.117, 3300.086, 3508.633, 3717.567, 3926.813, 4136.251, 4345.864, 4555.566, 4765.369, 4975.209, 5185.111, 5395.023 m
monthly means isoypycn surfaces:
1024, 1024.5, 1025, 1025.5, 1025.75, 1026, 1026.2, 1026.4, 1026.6, 1026.8, 1027, 1027.2, 1027.4, 1027.6, 1027.8, 1028 m
Temporal Jan 1980 to Dec 2015 by 1 month(s)
Jan 3, 1980 to Dec 20, 2015 by 5day(s)
Volume 3.3GB per year (monthly) / 523MB per year (monthly_iso)
571MB per day (5day)
Acquired January 9, 2017
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