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Regional solutions from GOCE data considering topographic-isostatic models. Annette Eicker, Torsten Mayer-Gürr, Atef Makloof, Karl-Heinz Ilk Institute of Theoretical Geodesy, University of Bonn November 6, 2006 GOCE User Workshop, Frascati. Introduction.
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Regional solutions from GOCE data considering topographic-isostatic models Annette Eicker, Torsten Mayer-Gürr, Atef Makloof, Karl-Heinz Ilk Institute of Theoretical Geodesy, University of Bonn November 6, 2006 GOCE User Workshop, Frascati
Introduction GOCE: high resolution static gravity field Regionally adapted refinements of the global field to optimally exploit the signal content Gravity field shows varying roughness in different geographic areas Regionally adapted regularization Consideration of topographic – isostatic models
Analysis concept GROOPS - Gravity Recovery Object Oriented Programming System Parameterization in space Observations Solver CHAMP sphericalharmonics localizingsplines normal- equations GRACE Parameterization in time conjugate gradients GOCE variance-component-estimation linearsplines mean values
Analysis concept GROOPS - Gravity Recovery Object Oriented Programming System Parameterization in space Observations Solver CHAMP sphericalharmonics localizingsplines normal- equations GRACE Parameterization in time conjugate gradients GOCE variance-component-estimation linearsplines mean values
Regional solutions • satellite data cut out over the regional • area • global solution subtracted as • reference field (e.g. GRACE field) • spline representation: • resolution: 67 km nodal point distance • => 5000 – 9000 parameters per region [cm]
Regional solutions • satellite data cut out over the regional • area • global solution subtracted as • reference field (e.g. GRACE field) • spline representation: • resolution: 67 km nodal point distance • => 5000 – 9000 parameters per region
Regional solutions • satellite data cut out over the regional • area • global solution subtracted as • reference field (e.g. GRACE field) • spline representation: • resolution: 67 km nodal point distance • => 5000 – 9000 parameters per region [cm]
Regional solutions • satellite data cut out over the regional • area • global solution subtracted as • reference field (e.g. GRACE field) • spline representation: • resolution: 67 km nodal point distance • => 5000 – 9000 parameters per region Degree variances [cm]
varying signal content in different regional areas => adaption of the regularization Regularization regularization parameter determined by variance component estimation
Regionally adapted regularization regularization continent
Regionally adapted regularization regularization continent regularization ocean
Combination of GRACE and GOCE „real“ Field: EGM96 up to degree 300reference field: GRACE solution up to n = 120, OSU91 from n = 121 GOCE refinements up to degree 300 30 days, sampling 5 sec. GRACE: SST: white noise,σ = 10 μm Orbits: white noise, σ = 3 cm GOCE: SGG: Txx, Tyy, Tzz, colored noise, σ = 1,2 mEOrbits: white noise, σ = 3 cm
Global „patching“-solution (quadrature) RMS: 6,71 cm nmax = 240
Uniform regularization per region RMS: 6,71 cm nmax = 240
Adapted regularization parameters RMS: 6,51 cm nmax = 240
Adapted regularization parameters RMS: 6,51 cm nmax = 240
Uniform regularization parameter [cm] RMS (uniform): 9,24 cm nmax = 240
Adapted regularization parameters [cm] RMS (uniform): 9,24 cm nmax = 240 RMS (adapted): 8,08 cm
Adapted regularization parameters RMS: 6,51 cm nmax = 240
Uniform regularization parameter [cm] RMS (uniform): 8,98 cm nmax = 240
Adapted regularization parameters [cm] RMS (uniform): 8,98 cm nmax = 240 RMS (adapted): 8,65 cm
signal error reference error combination Adapted regularization parameters RMS: 6,51 cm nmax = 240
Kruste Mantel Topographic-isostatic models Flexible tool for the combination with different kinds of prior information (global and regional) Previous test: combination with satellite data (GRACE) and global terrestrial data Next test: combination with gravity field signal derived from topographic – isostatic models
Topographic-isostatic models EGM96 uncompensated topography Pratt-Hayford
Without consideration of topography [cm] RMS (no topo): 10,42 cm nmax = 240
Pratt-Hayford, adapted regularization [cm] RMS (no topo): 10,42 cm nmax = 240 RMS (P.-H.): 9,12 cm
Summary and outlook Flexible tool for the combination with different kinds of prior information (global and regional) Improvement of the solution by regionally adapted regularization is possible => further refinement of the regularization areas Multiscale analysis => hierarchical splines, wavelets => timevariable, regional gravityfield (GRACE) GOCE real data analysis