Combined Gravity Field Model EIGEN-CG03C

Background

The gravity field combination model EIGEN-CG03C is an upgrade of EIGEN-CG01C. The model is based on the same CHAMP mission and surface data (0.5 x 0.5 deg. gravimetry and altimetry), but takes into account almost twice as much GRACE mission data. Instead of 200 days now 376 days out of February to May 2003, July to December 2003 and February to July 2004 have been used.

EIGEN-CG03C is complete to degree and order 360 in terms of spherical harmonic coefficients and resolves geoid and gravity anomaly wavelengths of 110 km. A special band-limited combination method has been applied in order to preserve the high accuracy from the satellite data in the lower frequency band of the geopotential and to form a smooth transition to the high frequency information coming from the surface data. Compared to pre-CHAMP/GRACE global high-resolution gravity models, the accuracy at 400 km wavelength could be improved by one order of magnitude to 3 cm and 0.4 mgal in terms of geoid heights and gravity anomalies, respectively. The overall accuracy of the full 360 model down to spatial features of 100 km is estimated to be 30 cm and 8 mgal, respectively. In general, the accuracy over the oceans is better than over the continents reflecting the quality of the available surface data.

The improvement w.r.t EIGEN-CG01C is reflected in the independent comparison with geoid heights determined point-wise by GPS positioning and GPS levelling. The table below shows the results for EGM96, CG01C and CG03C using GPS levelling data from the USA (Milbert, 1998), Canada (Veronneau, personal communication 2003; National Ressources Canada, GPS on BMs file, update February 2003) and Europe/Germany (Ihde et al., 2002).

Root mean square (rms) about mean of GPS-levelling minus gravity field model derived geoid heights [cm] (number of points in brackets).

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Download EIGEN-CG03C Data

• Format description of EIGEN-CG03C:
  
  g002_GR-GFZ-FD-001_v1.1.pdf (65 KB)
  
  
• EIGEN-CG03C gravity field coefficients:
  
  EIGEN_CG03C_coef (6.9 MB)
  EIGEN_CG03C_coef.gz (1.4 MB)
  
  
• Calibrated errors of EIGEN-CG03C modell:
  
  EIGEN_CG03C_err (2.5 MB)
  EIGEN_CG03C_err.gz (0.4 MB)
  
  

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References

A New High Resolution Global Gravity Field Model Derived From Combination of GRACE and CHAMP Mission and Altimetry/Gravimetry Surface Gravity Data
C. Förste(1), F. Flechtner(1), R. Schmidt(1), U. Meyer(1), R. Stubenvoll(1), F. Barthelmes(1), R. König(1), K.H. Neumayer(1), M. Rothacher(1), Ch. Reigber(1), R. Biancale(2), S. Bruinsma(2), J.-M. Lemoine(2), J.C. Raimondo(3)
(1) GeoForschungsZentrum Potsdam (GFZ), Dept. 1 Geodesy and Remote Sensing, Potsdam, Germany (2) Group de Recherche de Geodesie Spatiale (GRGS), Toulouse, France (3) Teleorbit GmbH, Dietramszell/Linden, Germany
Poster g004_EGU05-A-04561.pdf (316 KB) presented at EGU General Assembly 2005, Vienna, Austria, 24-29, April 2005

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GFZ, Department 1 Back

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Originator: Ch.Förste, F. Flechtner
May 19, 2005, webadmin A.Helm