Total Magnetic Intensity (TMI) greyscale Image of Australia 2019 with Variable Reduction to Pole (VRTP)

This image is a greyscale image of the Total Magnetic Intensity (TMI) Anomaly Image of Australia with Variable Reduction to Pole (VRTP).Total magnetic intensity (TMI) data measures variations in the intensity of the Earth magnetic filed caused by the contrasting content of rock-forming minerals in the Earth crust. Magnetic anomalies can be either positive (field stronger than normal) or negative (field weaker) depending on the susceptibility of the rock. A variable reduction to Pole is aimed at locating magnetic anomalies exactly above their source bodies and without any distortion. The image is created from the 2019 variable reduction to Pole of the TMI grid with a grid cell size of ~3 seconds of arc (approximately 80 m). This image only includes airborne-derived TMI data for onshore and near-offshore continental areas.The image provides a better interpretation of the magnetic data by giving an accurate location of magnetic source bodies.

本图像为采用变极距还原（Variable Reduction to Pole, VRTP）处理的澳大利亚总磁场强度（Total Magnetic Intensity, TMI）异常灰度图。总磁场强度数据用于表征由地壳中成岩矿物成分差异所引发的地球磁场强度变化。根据岩石磁化率的不同，磁异常可分为正异常（磁场强度高于正常值）与负异常（磁场强度低于正常值）两类。变极距还原处理的目标是将磁异常精准定位至其源体正上方，且不会产生任何畸变。本图像基于2019年TMI网格的变极距还原结果生成，网格单元尺寸约为3角秒（约合80米）。本图像仅涵盖陆上及近岸陆地区域的航空测量TMI数据。该图像通过精准定位磁异常源体，实现了对磁测数据更优质的解译。