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GEOPHYSICAL RESEARCH LETTERS, VOL. 29, NO. 24, 2210, doi:10.1029/2002GL016324, 2002

Site distribution and aliasing effects in the inversion for load coefficients and geocenter motion from GPS data

Xiaoping Wu

Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA


Donald F. Argus

Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA


Michael B. Heflin

Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA


Erik R. Ivins

Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA


Frank H. Webb

Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA


Abstract

Precise GPS measurements of elastic relative site displacements due to surface mass loading offer important constraints on global surface mass transport. We investigate effects of site distribution and aliasing by higher-degree (n ≥ 2) loading terms on inversion of GPS data for n = 1 load coefficients and geocenter motion. Covariance and simulation analyses are conducted to assess the sensitivity of the inversion to aliasing and mismodeling errors and possible uncertainties in the n = 1 load coefficient determination. We found that the use of center-of-figure approximation in the inverse formulation could cause 10–15% errors in the inverted load coefficients. n = 1 load estimates may be contaminated significantly by unknown higher-degree terms, depending on the load scenario and the GPS site distribution. The uncertainty in n = 1 zonal load estimate is at the level of 80–95% for two load scenarios.

Published 27 December 2002.

Index Terms: 1243 Geodesy and Gravity: Space geodetic surveys; 1223 Geodesy and Gravity: Ocean/Earth/atmosphere interactions (3339); 1645 Global Change: Solid Earth; 3260 Mathematical Geophysics: Inverse theory.

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Citation: Wu, X., D. F. Argus, M. B. Heflin, E. R. Ivins, and F. H. Webb (2002), Site distribution and aliasing effects in the inversion for load coefficients and geocenter motion from GPS data, Geophys. Res. Lett., 29(24), 2210, doi:10.1029/2002GL016324.