LAUSR

This article discusses methods for selecting criteria used for stopping iterative regularization methods applied to solving continuation of gravity observed at or outside the Earth’s surface down to the geoid. This computational step is required for determination of the gravimetric geoid by the Stokes approach. For surface gravity data measured with spatial resolutions at the kilometer level and higher, their downward continuation becomes ill posed and its solution numerically unstable. Two iterative methods often used for solving this problem, namely the Landweber and conjugate gradient least-squares methods, are investigated using a sample of surface gravity data synthesized from a global gravitational model over a mountainous test area in Colorado, USA. Five different commonly used stopping criteria are applied to both iterative methods and neither of them, except L-Curve, succeed to stop the iterative process at the reasonable solution. A simple approach is proposed to stop the iterative methods explo...