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Description

This dataset provides geometric parameters for the regular 0.5-degree lat-lon grid from the ECCO Version 4 Release 4 (V4r4) ocean and sea-ice state estimate. Parameters include areas and lengths of grid cell sides and the horizontal and vertical coordinates of grid cell centers and corners. Additional information related to the global domain geometry (e.g., bathymetry and land/ocean masks) are also included. However, users should note these domain geometry fields are approximations because they have been interpolated from the ECCO lat-lon-cap 90 (llc90) native model grid. Users interested in exact budget closure calculations for volume, heat, salt, or momentum should use ECCO fields provided on the llc90 grid. Estimating the Circulation and Climate of the Ocean (ECCO) 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 a global, nominally 1-degree 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
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
C2013583732-POCLOUD
Data State
COMPLETE
Number of Files/Granules
1
Processing Level
4
Science Keywords
Sea Ice Concentration

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 Geometry Parameters for the 0.5 degree Lat-Lon Model Grid (Version 4 Release 4) [Data set]. NASA Physical Oceanography Distributed Active Archive Center. https://doi.org/10.5067/ECG5A-GRD44 Date Accessed: 2025-12-16

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
area area of lat-lon grid cell m2 double 9.9692099683869E+36 N/A 1
Depth Model sea surface height (SSH) of 0m corresponds to an ocean surface at rest relative to the geoid. Depth corresponds to seafloor depth below geoid. Note: the MITgcm used by ECCO V4r4 implements 'partial cells' so model seafloor depth differs from the seafloor depth provided by the input bathymetry file. Also, this lat-lon gridded Depth field is spatially-averaged from the Depth field on the lat-lon-cap (llc90) model native grid. m double 9.9692099683869E+36 N/A 1
drF Nominal grid cell thickness. m float 9.96921E+36 N/A 1
hFacC Grid cells may be fractionally closed in the vertical. The open vertical fraction is hFacC. The model allows for partially-filled cells to represent topographic variations more smoothly (hFacC < 1). Completely closed (dry) tracer grid cells have hFacC = 0. Note: the lat-lon gridded hFacC is spatially-averaged from the hFacC field on the lat-lon-cap (llc90) model native grid. The total ocean volume of the ECCO V4r4 lat-lon gridded fields is within 0.05% of the total ocean volume of the native grid fields. 1 double 9.9692099683869E+36 N/A 1
latitude uniform grid spacing from -89.75 to 89.75 by 0.5 degrees_north float N/A N/A 1
latitude_bnds latitudes of grid cell edges 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 longitudes of grid cell edges N/A float N/A N/A 1
maskC True for grid cells with nonzero open vertical fraction (hFacC > 0), otherwise False. N/A byte 1 N/A 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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