1 / 14

Combination of GRACE and GOCE in situ data for high resolution regional gravity field modeling

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

zeal
Download Presentation

Combination of GRACE and GOCE in situ data for high resolution regional gravity field modeling

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 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 schmeer@gfz-potsdam.de

  2. Outline • GRACE in situ observations • New method using calibrated K-Band observations • Multi-resolution representation • Combination of GRACE and GOCE observations for regional application (simulation).

  3. Motivation Regional Gravity field Modeling In situ observations Representations

  4. GRACE 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): • Residual K-Band observations from GFZ processing-chain (EPOS-OC) for monthly GRACE solutions by applying reductions for: • static gravity field (EIGEN-4C/EIGEN-5C) • ocean and atmospheric mass variations (AOD) • third body attractions • ocean and solid earth tides

  5. GRACE in situ observations 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

  6. Theory of Multi-resolution Representation (MRR)

  7. Multi-resolution Representation 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)

  8. 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

  9. Results from MRR • Differences between GRACE L2 solution and method using calibrated K-Band observations. • characteristic patterns (stripes) • residual signal level decreasing (RL04 → RL05) • spherical scaling function = optimal filter March 2008 January 2008 Mass differences [EWH] between GRACE L2 solution (left: GRACE RL04 standards; right: GRACE RL05 standards) and method using calibrated K-Band observations.

  10. Inversion of observations into discrete values of geopotential 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)

  11. Integral Inversion • Numerical simulation • computation of residual observations from L2 models (EIGEN5C – EGM96) • introduction of spherical cap • definition of different zones (far and near zones) • calculation of normal equations, regularization • superposition of GRACE and GOCE equation system, inversion Mutltivariate Gauss-Markov model With observation vector Ifor combined observations from GRACE and GOCE For real data: variance components estimation, high-pass filtering

  12. Results: GRACE and GOCE-only 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]

  13. Results: Combination GRACE and GOCE Reproduction of residual signal by combination of GRACE and GOCE

  14. Conclusion • GRACE: Regional gravity field modeling using calibrated K- Band observations (residuals). • Differences between GRACE L2 und regional gravity field modeling reflecting in characteristic patterns (stripes). • Optimal filtering due to application of spherical scaling functions (MRR). • Validation with external data outstanding. • Combination of GRACE and GOCE: Integral inversion. • GRACE and GOCE spectral complementary. • Complementary coverage (e.g. Antarctica)

More Related