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Site distribution and aliasing effects in the inversion for load coefficients and geocenter motion from GPS data
Author(s) -
Wu Xiaoping,
Argus Donald F.,
Heflin Michael B.,
Ivins Erik R.,
Webb Frank H.
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl016324
Subject(s) - geodesy , global positioning system , inversion (geology) , covariance , aliasing , geology , environmental science , statistics , mathematics , computer science , seismology , telecommunications , artificial intelligence , undersampling , tectonics
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.