GRACEFO_L2_GFZ_MONTHLY_0060_1

PODAAC-GFL20-MG060

Version 1
  • Abstract
    FOR EXPERT USE ONLY. This dataset contains estimates of the total month-by-month geopotential of the Earth, derived from the Gravity Recovery and Climate Experiment Follow-On (GRACE-FO) mission measurements, produced by the German Research Centre for Geosciences (GFZ). The data are provided in spherical harmonic coefficients, averaged over approximately a month. The primary objective of the GRACE-FO mission is to obtain accurate estimates of the mean and time-variable components of the gravity field and corresponding Earth mass change variations, such as from polar ice sheets and mountain glaciers; total water storage on land (from groundwater changes in deep aquifers to changes in soil moisture and surface water); changes in deep ocean currents; and changes within the solid Earth itself, such as postglacial rebound and the impact of major earthquakes. This objective is achieved by making continuous measurements of the change in distance between twin spacecraft, co-orbiting in about 490 km altitude, near circular, polar orbit, spaced approximately 220+/-50 km apart, using a microwave ranging system. In addition to these inter-satellite range changes, the non-gravitational forces acting on each satellite are measured using a high accuracy electrostatic accelerometer. The satellite orientation and position (and timing) are precisely measured using star cameras (with three heads per satellite) and a GPS receiver. Spatial and temporal variations in the gravity field perturb the orbits (or trajectories) of the twin spacecraft differently. These differences lead to minute changes (on the order of tens of micrometers per second) in the distance between the spacecraft as they orbit the Earth. This change in distance (or range rate) 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 geopotential coefficients of an Earth gravity field model, typically on a per-month basis.

Data Identification Fields:

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    Data Dates
    Creation
    Last Revision
    Processing Level

    2

    Quality
    Collection Progress

    Not Provided

Related URLs
    Science Keywords
    • Earth Science
    • Solid Earth
    • GRAVITY/GRAVITATIONAL FIELD
    • Gravity

Acquisition Information Fields:

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Platforms
  • SPACECRAFT
    GRACE-FO
    Instruments
    • GRACE-FO KBR
    • GRACE-FO SCA
    • GRACE-FO ACC
    • GRACE-FO LRI

Temporal Information Fields:

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Spatial Information Fields:

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    Coverage Type Zone Identifier Geometry Granule Representation
    HORIZONTAL CARTESIAN CARTESIAN
Location Keywords
    • GEOGRAPHIC REGION
    • GLOBAL

Data Centers

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  • GRACE-FO/GFZ
    PROCESSOR

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  • PO.DAAC
    ARCHIVER

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  • Jet Propulsion Laboratory
    ARCHIVER

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Data Contacts

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  • Wen-Hao Li
    Data Center Contact
    Wen-Hao Li

    Jet Propulsion Laboratory

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Collection Citations Fields:

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Archive And Distribution Information Fields:

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    File Distribution Information
    • ASCII

      Format Type: Native