Print Email Facebook Twitter Optimizing estimates of annual variations and trends in geocentermotion and J2 from a combination of GRACE data and geophysical models Title Optimizing estimates of annual variations and trends in geocentermotion and J2 from a combination of GRACE data and geophysical models Author Sun, Y. (TU Delft Laboratory Geoscience and Remote Sensing) Riva, R.E.M. (TU Delft Physical and Space Geodesy) Ditmar, P.G. (TU Delft Physical and Space Geodesy) Date 2016-11-08 Abstract The focus of the study is optimizing the technique for estimating geocenter motion and variations in J2 by combining data from the Gravity Recovery and Climate Experiment (GRACE) satellite mission with output from an Ocean Bottom Pressure model and a Glacial Isostatic Adjustment (GIA) model. First, we conduct an end-to-end numerical simulation study. We generate input time-variable gravity field observations by perturbing a synthetic Earth model with realistically simulated errors. We show that it is important to avoid large errors at short wavelengths and signal leakage from land to ocean, as well as to account for self-attraction and loading effects. Second, the optimal implementation strategy is applied to real GRACE data. We show that the estimates of annual amplitude in geocenter motion are in line with estimates from other techniques, such as satellite laser ranging (SLR) and global GPS inversion. At the same time, annual amplitudes of C10 and C11 are increased by about 50% and 20%, respectively, compared to estimates based on Swenson et al. (2008). Estimates of J2 variations are by about 15% larger than SLR results in terms of annual amplitude. Linear trend estimates are dependent on the adopted GIA model but still comparable to some SLR results. To reference this document use: http://resolver.tudelft.nl/uuid:90639bc5-8737-4470-9306-c8eb7766be5e DOI https://doi.org/10.1002/2016JB013073 Embargo date 2017-05-09 ISSN 0148-0227 Source Journal of Geophysical Research, 121 (11), 8352-8370 Part of collection Institutional Repository Document type journal article Rights © 2016 Y. Sun, R.E.M. Riva, P.G. Ditmar Files PDF 2016_Sun_et_al_JGR.pdf 4.14 MB Close viewer /islandora/object/uuid:90639bc5-8737-4470-9306-c8eb7766be5e/datastream/OBJ/view