Combination of GRACE and GOCE in situ data for high resolution regional gravity field modeling. M. Schmeer 1 , C. Gruber 1 , M. Schmidt 2 , F. Flechtner 1 1 German Research Centre for Geosciences, Helmoltz Centre Potsdam (GFZ), Germany 2 German Geodetic Research Institut (DGFI), Germnay
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Combination of GRACE and GOCE in situ data for high resolution regional gravity field modeling
M. Schmeer1, C. Gruber1, M. Schmidt2, F. Flechtner1
1German Research Centre for Geosciences, Helmoltz Centre Potsdam (GFZ), Germany
2German Geodetic Research Institut (DGFI), Germnay
Regional Gravity field Modeling
In situ observations
Transformation of residual K-Band range rate observations relative to adjusted K-Band range rates from GFZ GRACE L2 processing into residual potential differences by simplified relation (Jekeli 1999):
Disturbing potential differences [m2/s2] across Africa and Europe relative to EIGEN-4C
GRACE L2 solution
Using calibrated K-Band observations
Correlation between GRACE L2 and method using calibrated K-Band observations > 0.80
Theory of Multi-resolution Representation (MRR)
Multi-resolution representation (MRR) splits an input signal into detail signals related to specific resolution levels, i.e., frequency bands: the higher the level the finer the spatial-temporal structures.
Modeling the spatial behavior of the gravity field by means of spherical scaling and wavelet functions, i.e., maintaining relation to spherical harmonics.
Example based on Blackman scaling function.
(Schmidt et al., 2007)
Results from MRR
MRR up to detail level i = 4
→spatial resolution comparable to spherical harmonics d/o = 60
Mass distributions [EWH] from regional gravity modeling using calibrated K-Band observations due to EIGEN-4C for Jan. 2008
Results from MRR
Mass differences [EWH] between GRACE L2 solution (left: GRACE RL04 standards; right: GRACE RL05 standards) and method using calibrated K-Band observations.
Integral inversion of GRACE data (Novák 2007)
Integral inversion based on scalar-valued integral kernels (locally extended) allows for evaluation of discrete values of gravitational functionals at a geocentric sphere.
GRACE: scalar-valued Abel-Poisson kernel function
GOCE: second order Abel-Poisson kernel function (non-scalar)
Mutltivariate Gauss-Markov model
With observation vector Ifor combined observations from GRACE and GOCE
For real data: variance components estimation, high-pass filtering
Regional gravity field recovery from GRACE and GOCE separately due to their spectral behaviour.
Simulated gravity field recovery (geoid height residuals) for GRACE (left) and GOCE (right) surrounded by low-resolution FAR-zone in [m]
Reproduction of residual signal by combination of GRACE and GOCE