Distribution of Magnetic Anomalies in China and Adjacent Areas Derived from CHAMP Satellite Data

Abstract

AbstractBased on the new and higher degree geomagnetic model POMME‐4.2S from CHAMP satellite data, we have calculated satellite magnetic anomalies and their vertical gradients at altitude 400 km in China and adjacent areas. The distributions of seven magnetic components are shown. In addition, we also compared the impact of the truncation level on the magnetic anomalies and analyzed the relationship between the anomalies and the lithospheric structure. The results indicate that the ∆X(∆Y) magnetic anomaly foci appear on the south (west) and north (east) sides of that of ∆Zin the main magnetic anomaly areas of the Sichuan, Tarim and Songliao basins. The configuration of the magnetic anomaly distribution is determined when the spherical harmonic model is up to 90 degrees, and only a minor modification to the magnetic anomaly is required for higher degrees. The anomaly and its vertical gradient are varying synchronously in the strong magnetic anomaly areas. The satellite magnetic anomaly has no direct corresponding relations with the topographic change, distribution of faults, depth of the Moho and the thickness of the lithosphere. However, this anomaly is connected with the depth of the Curie isotherm interface and the thickness of the magnetic layer, which is positive (negative) in the areas of deeper (shallower) Curie isotherm surface and thicker (thinner) magnetic layer.