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On regularized time varying gravity field models based on GRACE data and their comparisons with hydrological models
Royal Institute of Technology (KTH),Division of Geodesy and Geoinformatics.ORCID-id: 0000-0003-0067-8631
Department of Space Geodesy (GRGS), French Space Agency (CNES), Toulouse, France.
Department of Space Geodesy (GRGS), French Space Agency (CNES), Toulouse, France.
Department of Space Geodesy (GRGS), French Space Agency (CNES), Toulouse, France.
2013 (engelsk)Inngår i: Acta Geophysica, ISSN 1895-6572, Vol. 61, nr 1, s. 1-17Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Determination of spherical harmonic coefficients of the Earth's gravity field is often an ill-posed problem and leads to solving an ill-conditioned system of equations. Inversion of such a system is critical, as small errors of data will yield large variations in the result. Regularization is a method to solve such an unstable system of equations. In this study, direct methods of Tikhonov, truncated and damped singular value decomposition and iterative methods of ν, algebraic reconstruction technique, range restricted generalized minimum residual and conjugate gradient are used to solve the normal equations constructed based on range rate data of the gravity field and climate experiment (GRACE) for specific periods. Numerical studies show that the Tikhonov regularization and damped singular value decomposition methods for which the regularization parameter is estimated using quasioptimal criterion deliver the smoothest solutions. Each regularized solution is compared to the global land data assimilation system (GLDAS) hydrological model. The Tikhonov regularization with L-curve delivers a solution with high correlation with this model and a relatively small standard deviation over oceans. Among iterative methods, conjugate gradient is the most suited one for the same reasons and it has the shortest computation time

sted, utgiver, år, opplag, sider
Springer, 2013. Vol. 61, nr 1, s. 1-17
Emneord [en]
Gravity field and climate experiment, hydrological model, inversion, range-rate, smoothing
HSV kategori
Forskningsprogram
TEKNIK
Identifikatorer
URN: urn:nbn:se:hv:diva-5256DOI: 10.2478/s11600-012-0053-5ISI: 000311494300001OAI: oai:DiVA.org:hv-5256DiVA, id: diva2:615985
Tilgjengelig fra: 2013-04-14 Laget: 2013-04-14 Sist oppdatert: 2014-12-30bibliografisk kontrollert

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