On a spectral method for forward gravity field modelling. (July 2016)

• Record Type: Journal Article
• Authors: Root, B.C.; Novák, P.; Dirkx, D.; Kaban, M.; van der Wal, W.; Vermeersen, L.L.A.
• Is Part Of: Journal of geodynamics. Volume 97(2016)
• Page Start: 22
• Page End: 30
• Publication Date: 2016-07
• Subjects: Forward gravitational field modelling -- Spherical harmonic representation -- Global density models; Geodynamics -- Periodicals; Earth movements -- Periodicals; Rock deformation -- Periodicals; Earth -- Internal structure -- Periodicals; 551.1
• DOI: 10.1016/j.jog.2016.02.008
• Languages: English
• ISSNs: 0264-3707

Abstract

Abstract: This article reviews a spectral forward gravity field modelling method that was initially designed for topographic/isostatic mass reduction of gravity data. The method transforms 3D spherical density models into gravitational potential fields using a spherical harmonic representation. The binomial series approximation in the approach, which is crucial for its computational efficiency, is examined and an error analysis is performed. It is shown that, this method cannot be used for density layers in crustal and upper mantle regions, because it results in large errors in the modelled potential field. Here, a correction is proposed to mitigate this erroneous behaviour. The improved method is benchmarked with a tesseroid gravity field modelling method and is shown to be accurate within ±4 mGal for a layer representing the Moho density interface, which is below other errors in gravity field studies. After the proposed adjustment the method can be used for the global gravity modelling of the complete Earth's density structure.