Can we measure Geocenter Motion accurately?
Abstract
It is ten years since the IERS Campaign to investigate motion of the geocenter. One conclusion from that campaign was "It appears that even if Space Geodesy geocenter estimates are sensitive to seasonal variations, the determinations are not yet accurate and reliable enough to adopt an empirical model that would represent a real signal". So where are we 10 years later? Even putting aside the fact that we have ten years of new data, we have seen relatively dramatic improvements in data processing methodologies and models (e.g. atmospheric mapping and propagation functions, satellite force models and sub-daily ocean loading corrections) and the spatial expansion of geodetic networks. This period has also seen the development of a number of differing "deformation" estimation approaches, where geocenter motion can be inferred from purely geometric techniques (even VLBI) via the Earth's elastic properties. Even more recently, geocenter motion estimates are starting to appear from ranging to the GRACE satellites and via the combination of GRACE gravity fields with assumptions on land-ocean interactions. We compare estimates of geocenter motion in an attempt to gauge accuracy. We also present new estimates from re-processed GPS and SLR data using various direct and "deformation" inversion methods. We try as much as possible to investigate the effects of specific data processing changes upon the geocenter motion estimates.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFM.G33B0694L
- Keywords:
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- 1223 Ocean/Earth/atmosphere/hydrosphere/cryosphere interactions (0762;
- 1218;
- 3319;
- 4550);
- 1229 Reference systems;
- 1240 Satellite geodesy: results (6929;
- 7215;
- 7230;
- 7240)