Geocenter variations caused by atmosphere, ocean and surface ground water

Dong, Danan; Dickey, J. O.; Chao, Yi; Cheng, Minkang

doi:10.1029/97gl01849

Cited by 124 publications

(121 citation statements)

References 11 publications

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“…Apparent seasonal fluctuations between the center of mass and geocenter observed using SLR have peak-to-peak amplitudes of -40 mm, but such fluctuations average to a velocity insignificantly different from zero Eanes, 1993, 1997;Kar, 1997]. Seasonal fluctuations caused by observed variations in the atmosphere, the oceans, and the Earth's groundwater have peakto-peak amplitudes of-5 mm and average to a velocity of less than 1 mm/yr [Dong et al, 1997]. The current offset between the center of mass and the geocenter can be calculated using the spherical harmonic coefficients of Pavlis and Rapp [1990]: the geocenter is 1.2 km nearer the surface location 46øN, 34øE than the center of mass.…”

Section: Rebound-adjusted Geocenter Equals Center Of Mass (Rag=cm)mentioning

confidence: 99%

Glacial isostatic adjustment observed using very long baseline interferometry and satellite laser ranging geodesy

Argus¹,

Peltier²,

Watkins³

1999

J. Geophys. Res.

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Abstract. In global space geodetic solutions, radial site motions are usually estimated relative to the geocenter (the center of figure of the solid Earth). Most geodesists estimate the motion of the geocenter assuming both that sites do not move radially and that sites move laterally as predicted by plate motion model NUVEL-1A [DeMets et al., 1990[DeMets et al., , 1994]. Here we estimate the motion of the geocenter assuming that the plate interiors deform radially and laterally as predicted by the postglacial rebound model of Peltier [ 1994] or that of Peltier [ 1996] without assuming a priori knowledge about relative plate motion. Radial site motions estimated relative to this reboundadjusted geocenter are in the same reference frame as the rebound model predictions, whereas site motions estimated without adjusting for rebound are not. We further constrain the motion of the rebound-adjusted geocenter using satellite laser ranging's sensitivity to the center of mass (of the solid Earth, the oceans, and the atmosphere) by assuming that the mean velocity between the rebound-adjusted geocenter and the center of mass is negligible over the time period of geodetic measurement. Twenty years of observation with satellite laser ranging and very long baseline interferometry record the isostatic response of the solid Earth to the unloading of the late Pleistocene ice sheets. The misfits of the postglacial rebound model of Peltier [ 1994] and that of Peltier [1996] are 34% and 16% less, respectively, than the misfit of the rigid plate model. Sites at Onsala (Sweden) and Algonquin Park (Ontario) are observed to be rising at 3 mm/yr and 2 mm/yr, respectively, reflecting unloading of the Fennoscandian and Laurenfide ice sheets. Sites along the east coast of the United States are subsiding at < 2 mm/yr, indicating that the forebulge produced by the Laurentide ice sheet is currently collapsing very slowly. Sites beneath the margins of the ice sheets during the last glacial maximum are currently moving laterally away from the ice sheet centers at < 1.5 mm/yr, in disagreement with the moderately fast outward motion predicted by the model of Peltier [ 1996].

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Section: Rebound-adjusted Geocenter Equals Center Of Mass (Rag=cm)mentioning

confidence: 99%

Glacial isostatic adjustment observed using very long baseline interferometry and satellite laser ranging geodesy

Argus¹,

Peltier²,

Watkins³

1999

J. Geophys. Res.

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“…They concluded that the amplitudes of geocenter variations introduced by geophysical fluids (air and water) were less than I cm, about the same magnitude as the observed geocenter motions [Dong et al, 1997].…”

mentioning

confidence: 97%

Geophysical interpretation of observed geocenter variations

Chen¹,

Wilson²,

Eanes³

et al. 1999

J. Geophys. Res.

130

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“…[20] Global groundwater variations are expected to dominate the variations of the geocenter [Dong et al, 1997]. In this study, we ignored possible contribution (for all degrees) due to atmospheric loading, the next-largest contributor, and this approach may contribute to the 1.5 mm (RMS) GRACE-GPS disagreement.…”

Section: Componentmentioning

confidence: 99%

Climate‐driven deformation of the solid Earth from GRACE and GPS

Davis

Elósegui

Mitrovica

et al. 2004

Geophysical Research Letters

190

156

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[1] GRACE data indicate large seasonal variations in gravity that are assumed to be related to climate-driven fluxes of surface water. Seasonal redistribution of surface mass should deform the Earth, and our calculations using GRACE data suggest vertical deformations of $13 mm in the region of greatest flux, the Amazon River Basin. To test the GRACE gravity-hydrology connection, we analyzed GPS data acquired from sites in this region. After accounting for degree 1 variations not observable with GRACE, we find that annual deformation measured with GPS correlates highly with predictions calculated from GRACE measurements. These results confirm the variations in surface water sensed by GRACE, which are significantly larger than those predicted by some hydrology models. The results also demonstrate that GRACE can be an important tool for monitoring deformation of the Earth, and suggest that combined analysis of GRACE and GPS may be a useful approach for estimation of geocenter variations.

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Geocenter variations caused by atmosphere, ocean and surface ground water

Cited by 124 publications

References 11 publications

Glacial isostatic adjustment observed using very long baseline interferometry and satellite laser ranging geodesy

Glacial isostatic adjustment observed using very long baseline interferometry and satellite laser ranging geodesy

Geophysical interpretation of observed geocenter variations

Climate‐driven deformation of the solid Earth from GRACE and GPS

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