A New Method for Spectral Analysis of the Potential Field and Conversion of Derivatives of Gravity Anomalies: Cosine Transform

Abstract

Abstract In order to improve the accuracy of derivative conversion of gravity anomalies and reflect anomaly characteristics of geologic bodies effectively, we propose a new method of calculating anomaly derivatives using cosine transform. Two theorems are put forward and proved and the common expression of the cosine transform spectrum of the gravity potential field and formula to calculate derivatives of gravity anomalies are deduced. So a theory of cosine‐transform‐spectra of the potential‐field is established. In model experiments, we find that the deviation of the first derivative calculated by Fourier transform is very large comparing with the theoretical derivative, but the fitting effect of the anomaly derivative calculated by cosine transform is excellent. The calculation accuracy of data is all very high except that errors of several data on the boundary are large because of the residual Gibbus effect induced by finite truncation of gravity anomalies. Errors are –0.09%~5%.