Geophysical interpretation of observed geocenter variations

Chen, Jianli; Wilson, Curtis; Eanes, R. J.; Nerem, R. S.

doi:10.1029/1998jb900019

Cited by 98 publications

(138 citation statements)

References 12 publications

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“…The four test cases are: (1) the GRACE C 20 coefficient is omitted; (2) the GRACE C 20 coefficient is retained; (3) SLR values for C 20 and seasonal C 11 , S 11 , and C 10 are used (Chen et al 1999); and (4) SLR seasonal C 11 , S 11 , and C 10 are used, GRACE values of C 21 and S 21 are replaced with estimates from Earth Orientation Parameters (EOP) (Chen et al 2004), and SLR annual and semi-annual C 20 are substituted for GRACE values (Cheng and Tapley 2002).…”

Section: Grace Observationsmentioning

confidence: 99%

“…Degree-2 coefficients in GRACE products are currently not well determined (e.g., in the 0001 release as we use in this study) limited probably by orbit geometry and other unknown reasons (Tapley et al 2004b), and we experiment by replacing them with independent estimates from Earth rotation changes (Chen and Wilson 2003;Chambers et al 2004) and satellite laser ranging (SLR) observations (Cheng and Tapley 2002). GRACE does not measure degree-1 spherical harmonics, related to geocenter motion, but these are available from SLR observations (Chen et al 1999), and have a measurable effect on GRACE-derived sea level estimates.…”

Section: Introductionmentioning

confidence: 99%

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Seasonal global mean sea level change from satellite altimeter, GRACE, and geophysical models

Chen¹,

Wilson

Tapley³

et al. 2005

J Geodesy

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We estimate seasonal global mean sea level changes using different data resources, including sea level anomalies from satellite radar altimetry, ocean temperature and salinity from the World Ocean Atlas 2001, time-variable gravity observations from the Gravity Recovery and Climate Experiment (GRACE) mission, and terrestrial water storage and atmospheric water vapor changes from the NASA global land data assimilation system and National Centers for Environmental Prediction reanalysis atmospheric model. The results from all estimates are consistent in amplitude and phase at the annual period, in some cases with remarkably good agreement. The results provide a good measure of average annual variation of water stored within atmospheric, land, and ocean reservoirs. We examine how varied treatments of degree-2 and degree-1 spherical harmonics from GRACE, laser ranging, and Earth rotation variations affect GRACE mean sea level change estimates. We also show that correcting the standard equilibrium ocean pole tide correction for mass conser- vation is needed when using satellite altimeter data in global mean sea level studies. These encouraging results indicate that is reasonable to consider estimating longer-term time series of water storage in these reservoirs, as a way of tracking climate change.

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Section: Grace Observationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Seasonal global mean sea level change from satellite altimeter, GRACE, and geophysical models

Chen¹,

Wilson

Tapley³

et al. 2005

J Geodesy

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“…To be consistent with the reference frame used for T/P, the degree 1 coefficients, which are estimated from the variations of the Earth's center of mass proposed by Chen et al (1999), are added to the GRACE data.…”

Section: Gracementioning

confidence: 99%

Steric Sea-level Variations Inferred from Combined Topex/Poseidon Altimetry and GRACE Gravimetry

Garcia

Ramillien

Lombard

et al. 2007

Pure appl. geophys.

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In this study, we propose to estimate the steric sea level variations over a < 2-year period (April 2002 through December 2003) by combining global mean sea level (GMSL) based on Topex/Poseidon (T/P) altimetry with time-variable geoid averaged over the oceans, as observed by the GRACE (Gravity Recovery and Climate Experiment) satellite. In effect, altimetry-derived GMSL change results from two contributions: steric (thermal plus salinity) effects due to sea water density change and ocean mass change due to water exchange with atmosphere and continents. On the other hand, GRACE data over the oceans provide the ocean mass change component only.

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“…Geocenter motion is typically derived from satellite laser ranging (SLR) observations to geodetic satellites as, e.g., LAGEOS and STELLA, that relate the kinematic orbits of those satellites to stations realizing the terrestrial reference frame (Chen et al, 1999;Eanes, 2000;Cretaux et al, 2002). Alternatively, observations of the global network of GPS permanent stations allow also for the derivation of geocenter variations (Blewitt et al, 2001;Lavallée et al, 2006;Fritsche et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Global Eustatic Sea-Level Variations for the Approximation of Geocenter Motion from Grace

Bergmann-Wolf

Zhang

Dobslaw

2014

Journal of Geodetic Science

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Global degree-1 coe cients are derived by means of the method by Swenson et al. (2008) from a model of ocean mass variability and RL05 GRACE monthly mean gravity elds. Since an ocean model consistent with the GRACE GSM elds is required to solely include eustatic sea-level variability which can be safely assumed to be globally homogeneous, it can be empirically derived from GRACE as well, thereby allowing to approximate geocenter motion entirely out of the GRACE monthly mean gravity elds. Numerical experiments with a decade-long model time-series reveal that the methodology is generally robust both with respect to potential errors in the atmospheric part of AOD1B and assumptions on global degree-1 coe cients for the eustatic sea-level model. Good correspondence of the GRACE RL05-based geocenter estimates with independent results let us conclude that this approximate method for the geocenter motion is well suited to be used for oceanographic and hydrological applications of regional mass variability from GRACE, where otherwise an important part of the signal would be omitted.

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Geophysical interpretation of observed geocenter variations

Cited by 98 publications

References 12 publications

Seasonal global mean sea level change from satellite altimeter, GRACE, and geophysical models

Seasonal global mean sea level change from satellite altimeter, GRACE, and geophysical models

Steric Sea-level Variations Inferred from Combined Topex/Poseidon Altimetry and GRACE Gravimetry

Global Eustatic Sea-Level Variations for the Approximation of Geocenter Motion from Grace

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