Evaluation of EGM2008 by Comparison with Global and Local Gravity Solutions from CHAMP

authored by: M. Weigelt, N. Sneeuw, W. Keller
Abstract: New gravity field models incorporate GRACE data for the long wavelengths since it is one of the best available data sources. However, considering e.g. the degree difference RMS between EGM2008 and GGM02s, also discrepancies between these models occur which cannot solely be explained by numerical inaccuracies. Their validation is difficult since comparisons with existing GRACE models will always be biased. Maybe the best independent data set on a global scale is the CHAMP data. One the other hand, it is known that the accuracy of these solutions is approximately one order of magnitude worse than GRACE-only solutions. In this research, it has been investigated if CHAMP can serve as an indicator in the comparison of EGM2008 and GGM02s. The primary data source of CHAMP is its position and velocity measurements derived from GPS. They are based on purely kinematic orbits, which are independent of any a priori information and are provided by the Institute for Astronomical and Physical Geodesy at the Technical University Munich for the period of April 2002 to February 2004. The comparison is based on a global solution and a local refinement with Slepian functions in order to further improve the quality of the CHAMP solution. The latter is adopted because it can make better use of information in high-latitude areas where the data density is higher. However, the solutions are solely based on GPS measurements which have a poorer quality compared to the K-band ranging system of GRACE and thus prevents a real statement about the quality of the EGM2008.
Organisation(s): Institute of Geodesy
External Organisation(s): University of Stuttgart
Type: Conference contribution
Pages: 497-504
No. of pages: 8
Publication date: 2010
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Computers in Earth Sciences, Geophysics
Electronic version(s): https://doi.org/10.1007/978-3-642-10634-7_66 (Access: Unknown)
: Details in the research portal "Research@Leibniz University"

BibTeX

@inproceedings{35139eddb8a84ed59b1eaf656e9dc37b,
title = "Evaluation of EGM2008 by Comparison with Global and Local Gravity Solutions from CHAMP",
abstract = "New gravity field models incorporate GRACE data for the long wavelengths since it is one of the best available data sources. However, considering e.g. the degree difference RMS between EGM2008 and GGM02s, also discrepancies between these models occur which cannot solely be explained by numerical inaccuracies. Their validation is difficult since comparisons with existing GRACE models will always be biased. Maybe the best independent data set on a global scale is the CHAMP data. One the other hand, it is known that the accuracy of these solutions is approximately one order of magnitude worse than GRACE-only solutions. In this research, it has been investigated if CHAMP can serve as an indicator in the comparison of EGM2008 and GGM02s. The primary data source of CHAMP is its position and velocity measurements derived from GPS. They are based on purely kinematic orbits, which are independent of any a priori information and are provided by the Institute for Astronomical and Physical Geodesy at the Technical University Munich for the period of April 2002 to February 2004. The comparison is based on a global solution and a local refinement with Slepian functions in order to further improve the quality of the CHAMP solution. The latter is adopted because it can make better use of information in high-latitude areas where the data density is higher. However, the solutions are solely based on GPS measurements which have a poorer quality compared to the K-band ranging system of GRACE and thus prevents a real statement about the quality of the EGM2008.",
keywords = "CHAMP, Energy balance approach, GRACE, Slepian functions, Spherical harmonics",
author = "M. Weigelt and N. Sneeuw and W. Keller",
year = "2010",
doi = "10.1007/978-3-642-10634-7_66",
language = "English",
isbn = "9783642106330",
series = "International Association of Geodesy Symposia",
pages = "497--504",
booktitle = "Gravity, Geoid and Earth Observation - IAG Commission 2",
note = "IAG International Symposium on {"}Gravity, Geoid and Earth Observation 2008{"} ; Conference date: 23-06-2008 Through 27-06-2008",
}