Fri Apr 10, F. Flechtner
• Sorted by Date • Sorted by Last Name of First Author •
Yu, Nan, Wang, Jinghuan, and Li, Jiancheng, 2026. Improved geocentre motion estimates through the weighted combination of GRACE/GRACE–FO solutions and OBP models. Geophysical Journal International, 245(2):ggag053, doi:10.1093/gji/ggag053.
• from the NASA Astrophysics Data System • by the DOI System •
@ARTICLE{2026GeoJI.245..053Y,
author = {{Yu}, Nan and {Wang}, Jinghuan and {Li}, Jiancheng},
title = "{Improved geocentre motion estimates through the weighted combination of GRACE/GRACE-FO solutions and OBP models}",
journal = {Geophysical Journal International},
keywords = {Time-series analysis, Radar Interferometry Reference systems, Satellite gravity, Time variable gravity},
year = 2026,
month = may,
volume = {245},
number = {2},
eid = {ggag053},
pages = {ggag053},
abstract = "{Geocentre motion, defined as the displacement of Earth's centre of mass
relative to its centre of figure, is crucial for maintaining the
International Terrestrial Reference Frame origin and quantifying
large-scale mass redistribution. However, whether observing
geocentre motion by tracking satellite orbits or inferring it
using geophysical models, accurately acquiring such subtle
motions imposes stringent requirements on the consistency and
precision of both tracking data and geophysical models. This
study improves geocentre motion estimates derived from the
combination of GRACE/GRACE-FO time-variable gravity (TVG) and
Ocean Bottom Pressure (OBP) models (the GRACE-OBP method) in two
ways. First, we apply a forward modelling technique to mitigate
land─ocean leakage in GRACE/GRACE-FO TVG fields, which
demonstrably outperforms empirical coastline buffer-zone
corrections in controlled simulation experiments. Secondly, we
introduce the Bayesian Three-Cornered Hat (BTCH) method to
optimally combine geocentre series derived from multiple GRACE
solutions and two independent OBP models (Estimating the
Circulation and Climate of the Ocean, Phase II and Max Planck
Institute Ocean Model), producing an improved geocentre product
without requiring a ground-truth reference. Uncertainty analysis
shows that the noise level is governed primarily by the GRACE
solution, and that BTCH provides a clearer advantage over equal-
weighted averaging when the number of input series is limited,
reducing the noise level by about 30 per cent. After restoring
atmospheric and oceanic contributions, our improved geocentre
series shows good agreement with the CSR Satellite Laser
Ranging-derived geocentre product. Although uncertainty levels
vary among individual solutions, the estimated annual and
secular trend signals are broadly consistent and show limited
sensitivity to the choice of GRACE TVG solution and OBP model.
Using the improved geocentre series, we revisit the annual
geocentre oscillation and its drivers; the results indicate that
cryospheric mass variability and land─ocean mass exchange (i.e.
sea-level fingerprints) provide non-negligible contributions to
the annual geocentre cycle and improve consistency with
observations. Finally, the improved geocentre series yields the
lowest uncertainty in degree-1 mass variations, with a global
RMS of 0.55 mm. Incorporating these degree-1 terms into mass
budget assessments yields secular trends of 38.8 Gt
yr$^{{\ensuremath{-}}1}$ for the Antarctic Ice Sheet and 0.57 mm
yr$^{{\ensuremath{-}}1}$ for global mean ocean mass,
highlighting the need for accurate geocentre corrections to
support reliable long-term climate monitoring.}",
doi = {10.1093/gji/ggag053},
adsurl = {https://ui.adsabs.harvard.edu/abs/2026GeoJI.245..053Y},
adsnote = {Provided by the SAO/NASA Astrophysics Data System}
}
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