DATA
GRACE OCEAN BOTTOM GEOPOTENTIAL COEFFICIENTS CSR RELEASE 6.0 GAD
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DOI
10.5067/GRGAD-20C06
Short Name
GRACE_GAD_L2_GRAV_CSR_RL06
Description
FOR EXPERT USE ONLY. This dataset contains estimates of ocean bottom pressure derived from the Gravity Recovery and Climate Experiment (GRACE) mission measurements, produced by the Center for Space Research (CSR) at University of Texas at Austin. 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.
Version
6.0
Measurement
SOLID EARTH
› GRAVITY/GRAVITATIONAL FIELD
› GRAVITY
Processing Level
2
Coverage
Global
Northernmost Latitude
88.0
Southernmost Latitude
-88.0
Westernmost Longitude
-180.0
Easternmost Longitude
180.0
Time Span(s)
April 5, 2002 to
June 30, 2017
Resolution
Spatial Resolution
500.0 km (Along) x 500.0 km (Across)
Projection
-
Platform/Sensor
GRACE/GRACE SCA, GRACE/GRACE KBR, GRACE/GRACE ACC
Project
Gravity Recovery and Climate Experiment
(GRACE)
Data Provider
PO.DAAC