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Signal and noise in Gravity Recovery and Climate Experiment (GRACE) observed surface mass variationsSchrama, E.J.O. (author), Wouters, B. (author), Lavallée, D.A. (author)The Gravity Recovery and Climate Experiment (GRACE) product used for this study consists of 43 monthly potential coefficient sets released by the GRACE science team which are used to generate surface mass thickness grids expressed as equivalent water heights (EQWHs). We optimized both the smoothing radius and the level of approximation by...journal article 2007
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Riva, R.E.M. (author), Bamber, J.L. (author), Lavallée, D.A. (author), Wouters, B. (author)The Gravity Recovery and Climate Experiment satellites (GRACE) provide, for the first time, a method to directly measure mass exchange between the land and oceans over time. The dominant components of this exchange are due to continental ice loss/gain and land hydrology. Here, we determine the secular trend in these two components during the...journal article 2010
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Huang, J. (author), Halpenny, J. (author), Van der Wal, W. (author), Klatt, C. (author), James, T.S. (author), Rivera, A. (author)Groundwater is a primary hydrological reservoir of the Great Lakes Water Basin (GLB), which is an important region to both Canada and US in terms of culture, society and economy. Due to insufficient observations, there is a knowledge gap about groundwater storage variation and its interaction with the Great Lakes. The objective of this study is...journal article 2012
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Wouters, B. (author), Schrama, E.J.O. (author)One of the major problems one has to deal with when working with Gravity Recovery and Climate Experiment (GRACE) data is the increasing error spectrum at higher degrees in the provided Stokes coefficients, appearing as unphysical North?South striping patterns in the maps of equivalent water height (EWH). This phenomenon is commonly suppressed by...journal article 2007
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- Kusche, J. (author) journal article 2007
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Wouters, B. (author), Chambers, D. (author), Schrama, E.J.O. (author)Using satellite gravity data between February 2003 and January 2008, we examine changes in Greenland's mass distribution on a regional scale. During this period, Greenland lost mass at a mean rate of 179 ± 25 Gt/yr, equivalent to a global mean sea level change of 0.5 ± 0.1 mm/yr. Rates increase over time, suggesting an acceleration of the mass...journal article 2008
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Wouters, B. (author), Riva, R.E.M. (author), Lavallée, D.A. (author), Bamber, J.L. (author)Variations in the Earth's water cycle are commonly quantified by their effect on global mean sea?level. However, the interaction between passive adjustment of the ocean to changes in gravitational attraction due to mass redistribution, the related deformation of the solid Earth and disturbances in the Earth's rotation vector will yield a...journal article 2011
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Schrama, E.J.O. (author), Wouters, B. (author), Rietbroek, R. (author)The purpose of this paper is to assess the mass changes of the Greenland Ice Sheet (GrIS), Ice Sheets over Antarctica, and Land glaciers and Ice Caps with a global mascon method that yields monthly mass variations at 10,242 mascons. Input for this method are level 2 data from the Gravity Recovery and Climate Experiment (GRACE) system collected...journal article 2014
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Klees, R. (author), Liu, X. (author), Wittwe, T. (author), Gunter, B.C. (author), Revtova, E.A. (author), Tenzer, R. (author), Ditmar, P. (author), Winsemius, H.C. (author), Savenije, H.H.G. (author)When using GRACE as a tool for hydrology, many different gravity field model products are now available to the end user. The traditional spherical harmonics solutions produced from GRACE are typically obtained through an optimization of the gravity field data at the global scale, and are generated by a number of processing centers around the...journal article 2008
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Lavallée, D.A. (author), Moore, P. (author), Clarke, P.J. (author), Petrie, E.J. (author), Van Dam, T. (author), King, M.A. (author)Changes in J2, resulting from past and present changes in Earth's climate, are traditionally observed by Satellite Laser ranging (SLR). Assuming an elastic Earth, it is possible to infer changes in J2 from changes in Earth's shape observed by GPS. We compare estimates of non-secular J2 changes from GPS, SLR, GRACE, and a load model. The GPS and...journal article 2010
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Kusche, J. (author), Schrama, E.J.O. (author)Monitoring hydrological redistributions through their integrated gravitational effect is the primary aim of the Gravity Recovery and Climate Experiment (GRACE) mission. Time?variable gravity data from GRACE can be uniquely inverted to hydrology, since mass transfers located at or near the Earth's surface are much larger on shorter timescales...journal article 2005
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Han, S.C. (author), Riva, R.E.M. (author), Sauber, J. (author), Okal, E. (author)We quantify gravity changes after great earthquakes present within the 10 year long time series of monthly Gravity Recovery and Climate Experiment (GRACE) gravity fields. Using spherical harmonic normal-mode formulation, the respective source parameters of moment tensor and double-couple were estimated. For the 2004 Sumatra-Andaman earthquake,...journal article 2013
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Duan, X.J. (author), Guo, J.Y. (author), Shum, C.K. (author), Van der Wal, W. (author)We revisit the empirical moving window filtering method of Swenson and Wahr (Geophys Res Lett 33:L08402, 2006) and its variants, Chambers (Geophys Res Lett 33:L17603, 2006) and Chen et al. (Geophys Res Lett 34: L13302, 2007), for reducing the correlated errors in the Stokes coefficients (SCs) of the spherical harmonic expansion of the GRACE...journal article 2009
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Van der Wal, W. (author), Whitehouse, P.L. (author), Schrama, E.J.O. (author)Seismic data indicate that there are large viscosity variations in the mantle beneath Antarctica. Consideration of such variations would affect predictions of models of Glacial Isostatic Adjustment (GIA), which are used to correct satellite measurements of ice mass change. However, most GIA models used for that purpose have assumed the mantle to...journal article 2015
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Schrama, E.J.O. (author), Wouters, B. (author)In this paper we discuss a new method for determining mass time series for 16 hydrological basins representing the Greenland system (GS) whereby we rely on Gravity Recovery and Climate Experiment (GRACE) mission data. In the same analysis we also considered observed mass changes over Ellesmere Island, Baffin Island, Iceland, and Svalbard (EBIS)....journal article 2011
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Gunter, B. (author), Urban, T. (author), Riva, R. (author), Helsen, M. (author), Harpold, R. (author), Poole, S. (author), Nagel, P. (author), Schutz, B. (author), Tapley, B. (author)In this study, we present a comparison of coincident GRACE and ICESat data over Antarctica. The analysis focused on the secular changes over a 4-year period spanning from 2003 to 2007, using the recently reprocessed and publicly available data sets for both missions. The results show that the two independent data sets possess strong spatial...journal article 2009
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Broerse, D.B.T. (author), Vermeersen, L.L.A. (author), Riva, R.E.M. (author), Van der Wal, W. (author)Large earthquakes do not only heavily deform the crust in the vicinity of the fault, they also change the gravity field of the area affected by the earthquake due to mass redistribution in the upper layers of the Earth. Besides that, for sub-oceanic earthquakes deformation of the ocean floor causes relative sea level changes and mass...journal article 2011
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Ivins, E.R. (author), James, T.S. (author), Wahr, J. (author), Schrama, E.J.O. (author), Landerer, F.W. (author), Simon, K.M. (author)Antarctic volume changes during the past 21 thousand years are smaller than previously thought, and here we construct an ice sheet history that drives a forward model prediction of the glacial isostatic adjustment (GIA) gravity signal. The new model, in turn, should give predictions that are constrained with recent uplift data. The impact of the...journal article 2013
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- Schrama, E.J.O. (author), Visser, P.N.A.M. (author) journal article 2007
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Han, S.C. (author), Ditmar, P. (author)A spatiospectral localization method is discussed for processing the global geopotential coefficients from satellite mission data to investigate time-variable gravity. The time-variable mass variation signal usually appears associated with a particular geographical area yielding inherently regional structure, while the dependence of the...journal article 2007