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Fourier transform methods in local gravity modelingNew algorithms were derived for computing terrain corrections, all components of the attraction of the topography at the topographic surface and the gradients of these attractions. These algoriithms utilize fast Fourier transforms, but, in contrast to methods currently in use, all divergences of the integrals are removed during the analysis. Sequential methods employing a smooth intermediate reference surface were developed to avoid the very large transforms necessary when making computations at high resolution over a wide area. A new method for the numerical solution of Molodensky's problem was developed to mitigate the convergence difficulties that occur at short wavelengths with methods based on a Taylor series expansion. A trial field on a level surface is continued analytically to the topographic surface, and compared with that predicted from gravity observations. The difference is used to compute a correction to the trial field and the process iterated. Special techniques are employed to speed convergence and prevent oscillations. Three different spectral methods for fitting a point-mass set to a gravity field given on a regular grid at constant elevation are described. Two of the methods differ in the way that the spectrum of the point-mass set, which extends to infinite wave number, is matched to that of the gravity field which is band-limited. The third method is essentially a space-domain technique in which Fourier methods are used to solve a set of simultaneous equations.
Document ID
19900011222
Document Type
Conference Paper
Authors
Harrison, J. C. (Geodynamics Corp. Santa Barbara, CA, United States)
Dickinson, M. (Geodynamics Corp. Santa Barbara, CA, United States)
Date Acquired
September 6, 2013
Publication Date
June 1, 1989
Publication Information
Publication: Ohio State Univ., Progress in the Determination of the Earth's Gravity Field
Subject Category
GEOPHYSICS
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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IDRelationTitle19900011197Analytic PrimaryProgress in the Determination of the Earth's Gravity Field