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Description

This dataset provides daily-averaged ocean bottom pressure anomaly and sea surface height anomaly from the SASSIE ECCO Version 1 Release 1 (V1R1) ocean and sea-ice state estimate. ECCO (Estimating the Circulation and Climate of the Ocean) is a 4D ocean circulation model combining observations with a general circulation model (GCM) to estimate the complete time-evolving state of the global ocean. In this project, it was run over the Arctic polar region in support of the Salinity and Stratification at the Sea Ice Edge (SASSIE) field experiment - a NASA experiment focused on salinity anomalies in the upper ocean generated by melting sea ice. The SASSIE ECCO simulation was produced by downscaling the global ECCO state estimate from 1/3 to 1/12 degree grid cells, where the global solution provided initial and boundary conditions and atmospheric forcing. Model ocean and sea-ice state estimates are dynamically and kinematically-consistent reconstructions of the three-dimensional time-evolving ocean, sea-ice, and surface atmospheric states. The output fields for this dataset cover the period 2014-01-15T12:00:00 to 2021-02-07T12:00:00 and are consolidated onto a single curvilinear grid face focusing on the Arctic domain, using the 5 faces of the lat-lon-cap 1080 (llc1080) native grid from the original simulation. Daily files are available in netCDF-4.

This dataset is one of 22 produced by SASSIE ECCO - the full list can be found in the user guide. To cite all 22 datasets with a single DOI, please cite the user guide (citation details and DOI can be found within the user guide).

Version Description

Version 1, Release 1

Product Summary

Platforms
MITgcm
Location
ARCTIC
Coordinate System
GEODETIC
Granule Spatial Representation
GEODETIC
Temporal Extent
2014-01-15 to 2021-02-08
Temporal Resolution
1 Day
Data Partner
Physical Oceanography Distributed Active Archive Center, Jet Propulsion Laboratory, NASA (NASA/JPL/PODAAC)
Concept ID
C3675506855-POCLOUD
Data State
COMPLETE
Number of Files/Granules
2581
Processing Level
4
Science Keywords
Ocean Bottom Pressure ,
Sea Level Anomaly

Citation

Citation is critically important for dataset documentation and discovery. This dataset is openly shared, without restriction, in accordance with the EOSDIS Data Use and Citation Guidance.

Copy Citation

Marie Zahn, M. W. (2026). SASSIE ECCO Ocean Bottom Pressure and Sea Surface Height - Daily Mean llc1080 Grid (Version 1 Release 1) [Data set]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/SEL1D-OBP11 Date Accessed: 2026-03-15

Documents

Variables

The table below lists the variables contained within a single granule for this dataset. Variables often contain observed or derived geophysical measurements collected from a variety of sources, including remote sensing instruments on satellite and airborne platforms, field campaigns, in situ measurements, and model outputs. The terms variable, parameter, scientific data set, layer, and band have been used across NASA’s Earth science disciplines; however, variable is the designated nomenclature in NASA’s Common Metadata Repository (CMR). Variable metadata attributes such as Name, Description, Units, Data Type, Fill Value, Valid Range, and Scale Factor allow users to efficiently process and analyze the data. The full range of attributes may not be applicable to all variables. Additional information on variable attributes is typically available in the data, user guide, and/or other product documentation.

For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor Offset
ETAN Model sea level anomaly WITHOUT corrections for global mean density (steric) changes, inverted barometer effect, or volume displacement due to submerged sea-ice and snow. . Note: ETAN should NOT be used for comparisons with altimetry data products because ETAN is NOT corrected for (a) global mean steric sea level changes related to density changes in the Boussinesq volume-conserving model (Greatbatch correction, see sterGloH) nor (b) sea level displacement due to submerged sea-ice and snow (see sIceLoad). The model has no atmospheric pressure forcing so there is no need to make an inverted barometer correction. m float 9.96921E+36 -4.4207324981689 to 0.57575315237045 1 N/A
i In the Arakawa C-grid system, tracer (e.g., THETA) and 'v' variables (e.g., VVEL) have the same x coordinate on the model grid. N/A int N/A N/A 1 N/A
j In the Arakawa C-grid system, tracer (e.g., THETA) and 'u' variables (e.g., UVEL) have the same y coordinate on the model grid. N/A int N/A N/A 1 N/A
PHIBOT PHIBOT = p_b / rhoConst - g H(t), where p_b = hydrostatic ocean bottom pressure, rhoConst = reference density (1027.5 kg m-3), g is acceleration due to gravity (9.81 m s-2), and H(t) is model depth at time t. Units: p:[kg m-1 s-2], rhoConst:[kg m-3], g:[m s-2], H(t):[m]. Note: PHIBOT is NOT corrected for global mean steric sea level changes related to density changes in the Boussinesq volume-conserving model (Greatbatch correction), and therefore should NOT be used for comparisons with ocean bottom pressure data. m2 s-2 float 9.96921E+36 -77.738433837891 to 1064.8739013672 1 N/A
SSH Dynamic sea surface height anomaly above the geoid. Note: SSH is calculated by correcting model sea level anomaly ETAN for two effects: a) sea level displacement due to sea-ice and snow pressure loading (see sIceLoad), and b) the linear trend in ETAN. The linear trend is removed because the open boundary conditions have net zero inflow and outflow by model construction, so there is an accumulation of volume. This term can be compared with detrended altimetry data that has the inverse barometer (IB) correction. m float 9.96921E+36 0.29679974913597 to 1.8582049608231 1 N/A
time midpoint time of averaging period hours since 1992-01-01T12:00:00 int N/A N/A 1 N/A
time_bnds Start and end times of averaging period. N/A int N/A N/A 1 N/A
XC nonuniform grid spacing degrees_east float N/A -179.9994354248 to 179.99996948242 1 N/A
XC_bnds Bounds array follows CF conventions. XC_bnds[i,j,0] = 'southwest' corner (j-1, i-1), XC_bnds[i,j,1] = 'southeast' corner (j-1, i+1), XC_bnds[i,j,2] = 'northeast' corner (j+1, i+1), XC_bnds[i,j,3] = 'northwest' corner (j+1, i-1). Note: 'southwest', 'southeast', northwest', and 'northeast' do not correspond to geographic orientation but are used for convenience to describe the computational grid. See MITgcm documentation for details. N/A float N/A N/A 1 N/A
YC nonuniform grid spacing degrees_north float N/A 48.678619384766 to 89.978286743164 1 N/A
YC_bnds Bounds array follows CF conventions. YC_bnds[i,j,0] = 'southwest' corner (j-1, i-1), YC_bnds[i,j,1] = 'southeast' corner (j-1, i+1), YC_bnds[i,j,2] = 'northeast' corner (j+1, i+1), YC_bnds[i,j,3] = 'northwest' corner (j+1, i-1). Note: 'southwest', 'southeast', northwest', and 'northeast' do not correspond to geographic orientation but are used for convenience to describe the computational grid. See MITgcm documentation for details. N/A float N/A N/A 1 N/A
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