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Imaging · collection · 2018

GRACE OCEAN BOTTOM GEOPOTENTIAL COEFFICIENTS JPL RELEASE 6.0 GAD

Listed in NASA Earthdata CMR and NASA Data Portal — shown once because both records carry DOI 10.5067/grgad-20j06

FOR EXPERT USE ONLY.

Description

This dataset contains estimates of ocean bottom pressure derived from the Gravity Recovery and Climate Experiment (GRACE) mission measurements, produced by the NASA Jet Propulsion Laboratory (JPL). 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.

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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.

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Catalogue records · 3

Topics

Stated by source
Gravity Anomalies · Gravity Recovery and Climate Experiment · Ocean Bottom Pressure
From keywords
Astronomy & Astrophysics · Earth & Environmental Science · Ocean & Atmospheric Science · Physics
Provenance · 2 source records, 17 field assertions
SourceKeyLast seenRaw
NASA Earthdata CMRC2491772130-POCLOUD12 d agoJSON v1
NASA Data Portal6f458afd-389a-4efe-8c3a-ca56f8eafe3b9 d agoJSON v1
FieldAssertionExtractorEvidence
access_levelsource · NASA CMRconnector:nasa_cmr@1.0.0
concepts[field].local:field:astronomymapping · data nasa govconnector:data_nasa_gov@1.0.0
concepts[field].local:field:earth-environmentalmapping · data nasa govconnector:data_nasa_gov@1.0.0
concepts[field].local:field:ocean-atmosphericmapping · data nasa govconnector:data_nasa_gov@1.0.0
concepts[field].local:field:physicsmapping · data nasa govconnector:data_nasa_gov@1.0.0
concepts[measured_variable].gcmd:earth-science/oceans/ocean-pressure/ocean-bottom-pressuresource · NASA CMRconnector:nasa_cmr@1.0.0
concepts[measured_variable].gcmd:earth-science/solid-earth/gravity-gravitational-field/gravity-anomaliessource · NASA CMRconnector:nasa_cmr@1.0.0
concepts[platform].gcmd_platform:gracesource · NASA CMRconnector:nasa_cmr@1.0.0
created_datesource · NASA CMRconnector:nasa_cmr@1.0.0
descriptionsource · NASA CMRconnector:nasa_cmr@1.0.0/umm/Abstract
license_textsource · data nasa govconnector:data_nasa_gov@1.0.0
publication_datesource · NASA CMRconnector:nasa_cmr@1.0.0
spatialsource · NASA CMRconnector:nasa_cmr@1.0.0/umm/SpatialExtent
temporalsource · NASA CMRconnector:nasa_cmr@1.0.0/umm/TemporalExtents
titlesource · NASA CMRconnector:nasa_cmr@1.0.0/umm/EntryTitle
updated_datesource · NASA CMRconnector:nasa_cmr@1.0.0
version_labelsource · NASA CMRconnector:nasa_cmr@1.0.0