Gravity field modelling from airborne gravimetry using fundamental solutions of Laplace's equation in cartesian coordinates

Abstract

We present a new approach to reduce edge effects in regional gravity field modelling, which occur when fundamental solutions of Laplace's equation in Cartesian coordinates are used to parameterize the disturbing potential. The base functions implicitly assume periodicity of the gravity signal, which results in highly oscillating distortions in the adjusted gravity disturbances near the boundaries of the area. These distortions cause long-wavelength errors in the geoid solution over the whole area. A new method to solve this problem is introduced, which performs better than those tried earlier, such as zero-padding or data tapering. We demonstrate the performance of the developed methodology using airborne gravity data acquired during the CHICAGO survey performed by GFZ Potsdam, offshore the coast of Chile. To improve the results, we estimate nuisance parameters, such as scaling factors and biases, simultaneously with the gravity field parameters.