TELLUS Center of Space Research Weekly 5x5 Gravity Harmonics

TELLUS Center of Space Research Weekly 5x5 Gravity Harmonics
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DOI10.5067/TE5DE-COE01
Short NameTELLUS_DEG_5_COEF
DescriptionThis dataset provides weekly values of the spherical harmonic coefficients of the gravity field complete to degree and order 5, derived from satellite laser ranging up to five geodetic satellites, computed by Minkang Cheng, John Ries and Byron Tapley (2011). This is an experimental product; the coefficients of degree 3-5 are of lower quality than those of degree 1 and 2 by the nature of the tracking data. The data are provided for experienced users who wish to assess the quality of the product. The coefficients of degree 1 and 2 have clear physical interpretations. The degree 1 coefficients represent the relative position of the geocenter (the center of mass of the Earth) relative to the center of figure (defined, in practice, by the position of laser tracking stations on the surface of the Earth). The degree 2 order zero coefficient is described at http://grace.jpl.nasa.gov/data/get-data/gravity-harmonics/. The degree 2 order 1 coefficients are related to the relative position of the principal figure axis of the Earth relative to the rotational axis. In the absence of external torques, those two axes would be very close [Wahr, 1987 and 1990]. However, as a consequence of excitations due to tidal and other mass redistribution within the Earth system (dominated by seasonal variations), the two axes are not completely aligned, and the rotational axis precesses around the Earths principal figure axis (causing the approximate 435 day Chandler wobble).
Version1
Dataset TypePREVIEW
MeasurementSolid Earth > Geodetics/Gravity > Gravity
Processing Level2
CoverageRegion: Global
Northernmost Latitude: 89 degrees
Southernmost Latitude: -89 degrees
Westernmost Longitude: -180 degrees
Easternmost Longitude: 180 degrees
Time Span: 1992-Nov-05 to 2011-May-26
ResolutionSpatial Resolution: 4000 km (Along) x 4000 km (Across)
ProjectionType: Spherical
Detail:
Ellipsoid: WGS84
Latency hours
Swath Width- km
Sample Frequency-
Temporal Repeat (Nominal)1 Month
Temporal Repeat (Min)-
Temporal Repeat (Max)-
Platform/Sensor
TOPEX/POSEIDON
Platform
Name: Topography Experiment/Poseidon (TOPEX/POSEIDON)
Orbit Period: 112.43 minutes
Inclination Angle: 66.04 degrees
Ascending Node: 1970-Jan-01 00:00:00
/
LRA
SENSOR
Name: Laser Retroflector Array (LRA)
Swath Width: - km
Description: The LRA reflects signals from network of 10 to 15 satellite laser tracking stations to calibrate NRA bias and to provide the baseline tracking data for NASA precise orbit determination.

GRACE
Platform
Name: Gravity Recovery and Climate Experiment (GRACE)
Orbit Period: -1 minutes
Inclination Angle: 89 degrees
Ascending Node: 1970-Jan-01 00:00:00
/
GRACE ACC
SENSOR
Name: GRACE SuperSTAR Accelerometer (GRACE ACC)
Swath Width: - km
Description: The accelerometer, located at the center of mass of each satellite, measures all non-gravitational forces acting on each satellite. These forces include air drag, solar radiation pressure, and attitude control activator operation.

GRACE
Platform
Name: Gravity Recovery and Climate Experiment (GRACE)
Orbit Period: -1 minutes
Inclination Angle: 89 degrees
Ascending Node: 1970-Jan-01 00:00:00
/
GRACE SCA
SENSOR
Name: Star Camera Assembly (GRACE SCA)
Swath Width: - km
Description: The two star cameras mounted close to the accelerometer on each satellite provide the precise attitude references for the satellites when making science measurements.

GRACE
Platform
Name: Gravity Recovery and Climate Experiment (GRACE)
Orbit Period: -1 minutes
Inclination Angle: 89 degrees
Ascending Node: 1970-Jan-01 00:00:00
/
GRACE KBR
SENSOR
Name: K-Band Ranging System (GRACE KBR)
Swath Width: - km
Description: This instrument precisely measures the changes in the separation between the two GRACE satellites using phase tracking of K- and Ka-band signals sent between the two satellites

ProjectMaking Earth Science Data Records for Use in Research Environments (MEaSUREs)
Data ProviderCreator: M. Cheng, J. Ries and B. Tapley
Release Place: CSR
Release Date: 2011-Sep-13
Resource: http://grace.jpl.nasa.gov/data/get-data/gravity-harmonics/
Keyword(s)gravity
Persistent IDPODAAC-TE5DE-COE01
Questions related to this dataset? Contact podaac@podaac.jpl.nasa.gov
Direct Access
FTPftp://podaac.jpl.nasa.gov/allData/tellus/preview/L2/deg_5
Format (Compression)ASCII (NONE)
Citation M. Cheng, J. Ries and B. Tapley. 2011. TELLUS Center of Space Research Weekly 5x5 Gravity Harmonics. Ver. 1. PO.DAAC, CA, USA. Dataset accessed [YYYY-MM-DD] at http://dx.doi.org/10.5067/TE5DE-COE01.

For more information see Data Citations and Acknowledgments.

Journal Reference Cheng, M., J. C. Ries, and B. D. Tapley (2011), Variations of the Earths Figure Axis from Satellite Laser Ranging and GRACE, J. Geophys. Res., 116, B01409, 2011, DOI:10.1029/2010JB000850.