On the reliability and error calibration of some recent Earth's gravity models of GOCE with respect to EGM08
2013 (English)In: ACTA GEOD GEOPHYS, ISSN 2213-5812, Vol. 48, no 2, 199-208 p.Article in journal (Refereed) Published
The Gravity field and steady-state Ocean Circulation Explorer (GOCE) mission is dedicated to recover spherical harmonic coefficients of the Earth's gravity field to degree and order of about 250 using its satellite gradiometric data. Since these data are contaminated with coloured noise, therefore, their inversion will not be straightforward. Unsuccessful modelling of this noise will lead to biases in the harmonic coefficients presented in the Earth's gravity models (EGMs). In this study, five of the recent EGMs of GOCE such as two direct, two time-wise and one space-wise solution are used to degree and order 240 and their reliability is investigated with respect to EGM08 which is assumed as a reliable EGM. The detected unreliable coefficients and their errors are replaced by the corresponding ones from EGM08 as a combination strategy. A condition adjustment model is organised for each two corresponding coefficients of GOCE EGMs and EGM08; and errors of the GOCE EGMs are calibrated based on a scaling factor, obtained from a posteriori variance factor. When the factor is less than 2.5 it will be multiplied to the error otherwise the error of EGM08 coefficient will be considered as the calibrated one. At the end, a simple geoid estimator is presented which considers the EGMs and their errors and its outcomes are compared with the corresponding geoid heights derived from the Global Positioning System (GPS) and the levelling data (GPS/levelling data), over Fennoscandia. This comparison shows that some of the combined-calibrated GOCE EGMs are closer to the GPS/levelling data than the original ones.
Place, publisher, year, edition, pages
2013. Vol. 48, no 2, 199-208 p.
A posteriori variance factor, GOCE, GPS/levelling, EGM08, Degree of resolution, Signal and error spectra, Geoid, Scaling factor
IdentifiersURN: urn:nbn:se:kth:diva-124279DOI: 10.1007/s40328-013-0015-7ISI: 000319280300008ScopusID: 2-s2.0-84878659818OAI: oai:DiVA.org:kth-124279DiVA: diva2:634143
QC 201306282013-06-282013-06-282013-06-28Bibliographically approved