Spatial arrangement of equivalent sources in modeling gravitational anomalies

Abstract

A practical example is presented to examine various spatial arrangements of point masses for source-like approximation of discrete values of the anomalous gravitational field on a fragment of a spherical Earth. The WHU-CASM-UGM2025 global models of the Earth's gravity field and the GTOP030 global topography models were used as input data. The study area, measuring approximately 2.4 million square kilometers, is bounded by coordinates 50°–70° N, 150°–170° E. One or two depth levels for placing equivalent sources were used in the modeling process. Information on the observed field and the Earth's surface topography was specified either only for the study area or supplemented by data on the surrounding territory. Systems of equations were solved using direct methods, ensuring an approximation accuracy of at least 10-9 mGal. The results of eight computational experiments on recalculating gravity anomalies in the Bouguer reduction to the upper half-space are presented. It is established that the lack of field information outside the study area leads to artifacts in the calculation of transforms. Recommendations for improving the reliability of the equivalent source method results are provided.