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Description

This dataset contains daily-averaged ocean 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
Geographic Region
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
C1990404811-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 Ocean 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-OVE44 Date Accessed: 2025-12-14

Documents

Variables

Variables are a set of physical properties whose values determine the characteristics or behavior of something. For example, temperature and pressure are variables of the atmosphere. Parameters and variables can be used interchangeably. Variable level attributes provide individual information for each variable.

The Name in this table is the variable name. Fill value indicates missing or undefined data points in a variable. Valid range is the range of values the variable can store. Scale factor is used to increase or decrease the size of an object and can be used to correct for distortion. For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor
EVEL Zonal (east-west) component of ocean velocity. Note: EVEL is calculated by interpolating the model's x and y components of ocean velocity (UVEL and VVEL)to tracer cell centers and then finding the zonal component of the interpolated vectors. It is not recommended to use EVEL and NVEL for volume budget calculations because interpolating UVEL and VVEL from the model grid to the lat-lon grid introduces errors. Perform volume budget calculations with UVELMASS and VVELMASS on the native model grid. m s-1 float 9.96921E+36 -17.468323 to 19.48592 1
latitude uniform grid spacing from -89.75 to 89.75 by 0.5 degrees_north float N/A N/A 1
latitude_bnds latitude bounds grid cells N/A float N/A N/A 1
longitude uniform grid spacing from -179.75 to 179.75 by 0.5 degrees_east float N/A N/A 1
longitude_bnds longitude bounds grid cells N/A float N/A N/A 1
NVEL Meridional (north-south) component of ocean velocity. Note: NVEL is calculated by interpolating the model's x and y components of ocean velocity (UVEL and VVEL) to tracer cell centers and then finding the meridional component of the interpolated vectors. It is not recommended to use EVEL and NVEL for volume budget calculations because interpolating UVEL and VVEL from the model grid to the lat-lon grid introduces errors. Perform volume budget calculations with UVELMASS and VVELMASS on the native model grid. m s-1 float 9.96921E+36 -12.522369 to 20.500051 1
time center time of averaging period hours since 1992-01-01T12:00:00 int N/A N/A 1
time_bnds Start and end times of averaging period. N/A int N/A N/A 1
WVEL Vertical velocity in the +z direction at the top face of the grid cell. 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 -0.02315066 to 0.016380994 1
Z Non-uniform vertical spacing. m float N/A N/A 1
Z_bnds One pair of bounds for each vertical level. N/A float N/A N/A 1
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