Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Skip to content


Metadata Updated: December 6, 2023

FOR EXPERT USE ONLY. This dataset contains estimates of geopotential field derived from the Gravity Recovery and Climate Experiment (GRACE) mission measurements and a non-tidal oceanic model produced by the German Research Centre for Geosciences (GFZ). The data are in spherical harmonics averaged over approximately a month. The primary objective of the GRACE mission is to obtain accurate estimates of the mean and time-variable components of the gravity field variations. This objective is achieved by making continuous measurements of the change in distance between twin spacecraft, co-orbiting in about 500 km altitude, near circular, polar orbit, spaced approximately 200 km apart, using a microwave ranging system. In addition to these range change, the non-gravitional forces are measured on each satellite using a high accuracy electrostatic, room-temperature accelerometer. The satellite orientation and position (and timing) are precisely measured using twin star cameras and a GPS receiver, respectively. Spatial and temporal variations in the gravity field affect the orbits (or trajectories) of the twin spacecraft differently. These differences are manifested as changes in the distance between the spacecraft, as they orbit the Earth. This change in distance is reflected in the time-of-flight of microwave signals transmitted and received nearly simultaneously between the two spacecraft. The change in this time of fight is continuously measured by tracking the phase of the microwave carrier signals. The so called dual-one-way range change measurements can be reconstructed from these phase measurements. This range change (or its numerically derived derivatives), along with other mission and ancillary data, is subsequently analyzed to extract the parameters of an Earth gravity field model.

Access & Use Information

Public: This dataset is intended for public access and use. License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

Downloads & Resources


Metadata Created Date May 30, 2023
Metadata Updated Date December 6, 2023

Metadata Source

Harvested from NASA Data.json

Graphic Preview


Additional Metadata

Resource Type Dataset
Metadata Created Date May 30, 2023
Metadata Updated Date December 6, 2023
Identifier C2491772116-POCLOUD
Data First Published 2018-08-06
Language en-US
Data Last Modified 2018-08-06
Category GRACE, geospatial
Public Access Level public
Bureau Code 026:00
Metadata Context
Metadata Catalog ID
Schema Version
Catalog Describedby
Citation GRACE. 2018-08-31. GRACE NON-TIDAL OCEAN GEOPOTENTIAL COEFFICIENTS GFZ (GAB). Version 6.0. GRACE_GAB_L2_GRAV_GFZ_RL06. JPL PO.DAAC. Archived by National Aeronautics and Space Administration, U.S. Government, GFZ. GRACE, GFZ, 2018-08-31, GRACE NON-TIDAL OCEAN GEOPOTENTIAL COEFFICIENTS GFZ RELEASE 6.0 GAB,
Creator GRACE
Graphic Preview Description Thumbnail
Graphic Preview File
Harvest Object Id b9718554-30dd-467b-a762-f433714496e0
Harvest Source Id 58f92550-7a01-4f00-b1b2-8dc953bd598f
Harvest Source Title NASA Data.json
Homepage URL
Metadata Type geospatial
Old Spatial -180.0 -88.0 180.0 88.0
Program Code 026:001
Release Place JPL PO.DAAC
Source Datajson Identifier True
Source Hash 7396dfebc7042effb63239a63c6b42a804c10e1799634a08385fe04c9a3a42b6
Source Schema Version 1.1
Temporal 2002-04-05T00:00:00Z/2017-07-01T00:00:00Z

Didn't find what you're looking for? Suggest a dataset here.