HR: 11:05h
AN: G51C-04    [PDF]
TI: Effect of Mapping Function Errors on Estimates of Surface Mass Changes
AU: van Dam, T M
EM: tonie@ecgs.lu
AF: European Center for Geodynamics and Seismology, 19 Rue Josy Welter, Walferdange, L-7233 Luxembourg
AU: * Niell, A
EM: aniell@haystack.mit.edu
AF: MIT Haystack Observatory, Off Rte 40, Westford, MA 01886 United States
AB: Temporal variations in the spatial distribution of atmospheric, hydrologic, and oceanic mass causes significant deformation of the solid Earth at periods ranging from daily to annual. Such deformation is not only detectable with modern geodetic techniques but is a strong component of many GPS coordinate time series. In fact, using a global GPS tracking network it has been demonstrated that it is possible to invert for a truncated spherical harmonic expansion of the Earth's geometric shape. This deformation, combined with an elastic earth model, can be used to estimate spherical harmonic coefficients of the surface mass load. In this way, we can determine surface mass distributions that are consistent and that conserve mass in terms of the global water budget. One problem with this approach to deriving the surface mass variations is spatial correlation between the loading signal and inadequate modelling of the zenith tropospheric delay (ZTD). Correlations between these signals will affect our estimates of the amplitude of the mass load. In this paper, we compare the spatial and temporal variations of modeling errors in the ZTD with various loading phenomena and estimate the amplitude of the effect.
DE: 1200 GEODESY AND GRAVITY
DE: 1229 Reference systems
DE: 1243 Space geodetic surveys
DE: 1294 Instruments and techniques
DE: 1299 General or miscellaneous
SC: Geodesy [G]
MN: 2003 Fall Meeting