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Description

This dataset contains daily-averaged Gent-McWilliams ocean bolus velocity interpolated to a regular 0.5-degree grid from the ECCO Version 4 revision 4 (V4r4) ocean and sea-ice state estimate. Estimating the Circulation and Climate of the Ocean (ECCO) 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. ECCO V4r4 is a free-running solution of the 1-degree global configuration of the MIT general circulation model (MITgcm) that has been fit to observations in a least-squares sense. Observational data constraints used in V4r4 include sea surface height (SSH) from satellite altimeters [ERS-1/2, TOPEX/Poseidon, GFO, ENVISAT, Jason-1,2,3, CryoSat-2, and SARAL/AltiKa]; sea surface temperature (SST) from satellite radiometers [AVHRR], sea surface salinity (SSS) from the Aquarius satellite radiometer/scatterometer, ocean bottom pressure (OBP) from the GRACE satellite gravimeter; sea ice concentration from satellite radiometers [SSM/I and SSMIS], and in-situ ocean temperature and salinity measured with conductivity-temperature-depth (CTD) sensors and expendable bathythermographs (XBTs) from several programs [e.g., WOCE, GO-SHIP, Argo, and others] and platforms [e.g.,research vessels, gliders, moorings, ice-tethered profilers, and instrumented pinnipeds]. V4r4 covers the period 1992-01-01T12:00:00 to 2018-01-01T00:00:00.

Product Summary

Platforms
MODELS ,
MITgcm
Spatial Extent

N: 90 S: -90 E: 180 W: -180

Spatial Resolution
0.5 Decimal Degrees x 0.5 Decimal Degrees
Location
GLOBAL OCEAN
Coordinate System
CARTESIAN
Granule Spatial Representation
CARTESIAN
Temporal Extent
1992-01-01 to 2018-01-01
Data Partner
Physical Oceanography Distributed Active Archive Center, Jet Propulsion Laboratory, NASA (NASA/JPL/PODAAC)
Concept ID
C1990404807-POCLOUD
Data State
COMPLETE
Number of Files/Granules
9497
Processing Level
4
Published
Science Keywords
Ocean Circulation ,
Ocean Currents

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

Fenty, I., & Wang, O. (2020). ECCO Gent-McWilliams Ocean Bolus Velocity - Daily Mean 0.5 Degree (Version 4 release 4) [Data set]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/ECG5D-BOL44 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
EVELSTAR Zonal (east-west) component of the Gent-McWilliams bolus ocean velocity. Note: EVELSTAR is calculated by interpolating the model's x and y components of GM bolus ocean velocity (UVELSTAR and VVELSTAR) to tracer cell centers and then finding the zonal components of the interpolated vectors. One should take care when interpreting bolus velocities interpolated from the ECCO native model grid because interpolating from the model grid to the lat-lon grid introduces errors. Some closed buget calculations require bolus velocity terms on the native model grid. m s-1 float 9.96921E+36 -5.8322334 to 7.810458 1 N/A
latitude uniform grid spacing from -89.75 to 89.75 by 0.5 degrees_north float N/A N/A 1 N/A
latitude_bnds latitude bounds grid cells N/A float N/A N/A 1 N/A
longitude uniform grid spacing from -179.75 to 179.75 by 0.5 degrees_east float N/A N/A 1 N/A
longitude_bnds longitude bounds grid cells N/A float N/A N/A 1 N/A
NVELSTAR Meridional (north-south) component of the Gent-McWilliams bolus ocean velocity. Note: NVELSTAR is calculated by interpolating the model's x and y components of GM bolus ocean velocity (UVELSTAR and VVELSTAR) to tracer cell centers and then finding the meridional components of the interpolated vectors. One should take care when interpreting bolus velocities interpolated from the ECCO native model grid because interpolating from the model grid to the lat-lon grid introduces errors. Some closed buget calculations require bolus velocity terms on the native model grid m s-1 float 9.96921E+36 -6.4728584 to 6.751338 1 N/A
time center 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
WVELSTAR Vertical component of the Gent-McWilliams bolus ocean velocity. Note: in the Arakawa-C grid used in ECCO V4r4, vertical velocities are staggered relative to the tracer cell centers with values at the TOP and BOTTOM faces of each grid cell. m s-1 float 9.96921E+36 -0.0037936007 to 0.0040190346 1 N/A
Z Non-uniform vertical spacing. m float N/A N/A 1 N/A
Z_bnds One pair of bounds for each vertical level. N/A float N/A N/A 1 N/A
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