Distribution of the magnetic anomaly for the CHAMP satellite in China and adjacent areas

Based on the new and higher degree geomagnetic model POMME-4.2S from CHAMP satellite data, we have calculated the satellite magnetic anomaly and its vertical gradient at 400 km altitude 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 anomaly and analyzed the relationship of the anomaly and the lithospheric structure.The results indicate that, the ΔX (ΔY) magnetic anomalies foci appear on the south (west) and north (east) sides of that of ΔZ, in the main magnetic anomaly areas of 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 available 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, the zone of rupture, the depth of Moho and the thickness of the lithosphere.However, this anomaly is connected with the depth of the Curie isotherm surface 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.