Item

Abstract

Magnetic anomaly grids over a large region are usually produced by compiling the multiple geomagnetic field survey data sets. Because of many reasons, the systematic discrepancies among different surveys result in inevitably long wavelength distortions, and further bring difficulties to the fusion of near surface and satellite data sets. To deal with this problem, based on the Revised Spherical Cap Harmonic Analysis (R-SCHA for short) method, we proposed an extraction, evaluation and replacement techniques of long wavelength components from regional magnetic anomaly compiled grids. After testing the validity by the synthetic observing data and the theoretical data, the method is practically applied to the grid data (7^th version) of aeromagnetic anomaly over the Australia. Finally, the compiled aeromagnetic anomaly data sets with and without long wavelength component replacement are respectively adopted to R-SCHA modelling combined with the CHAMP satellite magnetic vector data. The results show that, the fusion performance is better if using the compiled aeromagnetic anomaly data set with the long wavelength component replacement, and there is the incompatibility or the inconsistency between the long wavelength components of the compiled aeromagnetic anomaly data and the satellite magnetic measurements. In brief, the synthetic test and the practical application verify the reliability and practicability of the proposed method, and thus can be effectively applied to the regional aeromagnetic anomaly data compilation.