Abstract
We have analyzed recent gravity recovery and climate experiment (GRACE) RL04 monthly gravity solutions, using a new decorrelating post-processing approach. We find very good agreement with mass anomalies derived from a global hydrological model. The post-processed GRACE solutions exhibit only little amplitude damping and an almost negligible phase shift and period distortion for relevant hydrological basins. Furthermore, these post-processed GRACE solutions have been inspected in terms of data fit with respect to the original inter-satellite ranging and to SLR and GPS observations. This kind of comparison is new. We find variations of the data fit due to solution post-processing only within very narrow limits. This confirms our suspicion that GRACE data do not firmly ‘pinpoint’ the standard unconstrained solutions. Regarding the original Kusche (J Geod 81:733–749, 2007) decorrelation and smoothing method, a simplified (order-convolution) approach has been developed. This simplified approach allows to realize a higher resolution—as necessary, e.g., for generating computed GRACE observations—and needs far less coefficients to be stored.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Chambers D, Wahr J, Nerem RS (2004) Preliminary observations of global ocean mass variations with GRACE. Geophys Res Lett 33. doi:10.1029/2004GL020461
Colombo OL (1986) Notes on the mapping of the gravity field using satellite data. In: Sünkel H (ed) Mathematical and numerical techniques in physical geodesy. Lecture notes in earth Sciences, vol 7. Springer, Berlin
Davis J, Tamisea M, Elósegui P, Mitrovica J, Hill E (2008) A statistical filtering approach for Gravity Recovery and Climate Experiment (GRACE) gravity data. J Geophys Res/Solid Earth 113: B04410. doi:10.1029/2007JB005043
Döll P, Kaspar F, Lehner B (2003) A global hydrological model for deriving water availability indicators: model tuning and validation. J Hydrol 270(1–2): 105–134
Fenoglio-Marc L, Kusche J, Becker M (2006) Mass variation in the Mediterranean Sea and its validation by altimetry, steric and hydrologic fields. Geophys Res Lett 33. doi:10.1029/2006GL026851
Flechtner F (2007) GFZ Level-2 processing standards document for level-2 product release 0004, GRACE 327-743, Rev. 1.0
Güntner A (2008) Improvement of global hydrological models using GRACE data. Surv Geophys. doi:10.1007/s10712-008-9038-y
Gunter B, Ries J, Bettadpur S, Tapley B (2006) A simulation study of the errors of omission and commission for GRACE RL01 gravity fields. J Geod. doi:10.1007/s00190-006-0083-3
Han S-C, Simons F (2008) Spatiospectral localization of global geopotential fields from the gravity recovery and climate experiment (GRACE) reveals the coseismic gravity change owing to the 2004 Sumatra–Andaman earthquake. J Geophys Res/Solid Earth 113: B01405. doi:10.1029/2007JB004927
Klees R, Revtova E, Gunter B, Ditmar P, Oudman E, Winsemius H, Savenije H (2008) The design of an optimal filter for monthly GRACE gravity models. Geophys J Int. doi:10.1011/j.1365-246X.2008.03922.x
Kusche J (2007) Approximate decorrelation and non-isotropic smoothing of time-variable GRACE-type gravity field models. J Geod 81: 733–749. doi:10.1007/s00190-007-0143-3
Parker RL (1994) Geophysical inverse theory. Princeton University Press, New Jersey
Petrovic S, Schmidt R, Wünsch J, Barthelmes F, Güntner A, Rothacher M (2007) Towards a characterization of temporal gravity field variations in GRACE observations and global hydrology models. J Mapping 18: 199–204
Schmidt R, Schwintzer P, Flechtner F, Reigber C, Güntner A, Döll P, Ramillien G, Cazenave A, Petrovic S, Jochmann H, Wünsch J (2006) GRACE observations of changes in continental water storage. Glob Planet Change 50(1–2): 112–126
Schmidt R, Petrovic S, Güntner A, Barthelmes F, Wünsch J, Kusche J (2008a) Periodic components of water storage changes from GRACE and global hydrology models. J Geophys Res/Solid Earth. doi:10.1029/2007JB005363
Schmidt R, Flechtner F, Meyer U, Neumayer K-H, Dahle C, König R, Kusche J (2008b) Hydrological signals observed by the GRACE satellites. Surv Geophys. doi:10.1007/s10712-008-9033-3
Swenson S, Wahr J (2006) Post-processing removal of correlated errors in GRACE data. Geophys Res Lett 33: L08402. doi:10.1029/2005GL025285
Swenson S, Wahr J (2007) Multi-sensor analysis of water storage variations in the Caspian Sea. Geophys Res Lett 34: L16401. doi:10.1029/2007GL030733
Tapley B, Bettadpur S, Ries J, Thompson P, Watkins M (2004a) GRACE measurements of mass variability in the Earth system. Science 305: 503–505
Tapley B, Bettadpur S, Watkins M, Reigber C (2004) The gravity recovery and climate experiment: Mission overview and early results. Geophys Res Lett 31: L09607. doi:10.1029/2004GL019920
Wahr J, Molenaar M, Bryan F (1998) Time variability of the Earth’s gravity field: hydrological and oceanic effects and their possible detection using GRACE. J Geophy Res/Solid Earth 108(B12):30,205–30,229
Wouters B, Schrama EJO (2007) Improved accuracy of GRACE gravity solutions through empirical orthogonal function filtering of spherical harmonics. Geophys Res Lett 34: L23711. doi:10.1029/2007GL032098
Velicogna I, Wahr J (2006) Measurements of time-variable gravity show mass loss in Antarctica. Science 311: 1754
Author information
Authors and Affiliations
Corresponding author
Electronic supplementary material
The Below is the Electronic Supplementary Material.
Rights and permissions
About this article
Cite this article
Kusche, J., Schmidt, R., Petrovic, S. et al. Decorrelated GRACE time-variable gravity solutions by GFZ, and their validation using a hydrological model. J Geod 83, 903–913 (2009). https://doi.org/10.1007/s00190-009-0308-3
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00190-009-0308-3