Tanami EW 5N - TMI grid (AWAGS)

Total magnetic intensity (TMI) data measures variations in the intensity of the Earth's magnetic field 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. The data are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface. The processed data is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose.This Tanami EW 5N - TMI grid (AWAGS) has a cell size of 0.00018 degrees (approximately 20m). The units are in nanoTesla (or nT). The data used to produce this grid was acquired in 2018 by the NT Government, and consisted of 11735 line-kilometres of data at 100m line spacing and 60m terrain clearance. To constrain long wavelengths in the grid, an independent data set, the Australia-wide Airborne Geophysical Survey (AWAGS) airborne magnetic data, was used to control the base levels of the survey grid.

总磁场强度（Total magnetic intensity, TMI）数据用于测量地壳内造岩矿物组分差异所引发的地球磁场强度变化。根据岩石的磁化率差异，磁异常可分为正异常（磁场强度高于常规背景）与负异常（磁场强度低于常规背景）两类。该数据集已通过标准化处理流程进行校正，确保所记录的磁场响应仅源自地下岩体。经处理后的数据可通过解译揭示地下地质结构。本数据集经GA地球物理学家开展质量核查，确保GA发布的最终数据满足应用需求。本次发布的Tanami EW 5N - TMI网格（Australia-wide Airborne Geophysical Survey, AWAGS）的网格单元尺寸为0.00018度（约20米），数据单位为纳特斯拉（nanoTesla, nT）。用于生成该网格的原始数据由北领地（NT）政府于2018年采集，总测线长度达11735测线公里，测线间距为100米，飞行离地高度为60米。为约束该网格中的长波长信号，研究人员采用AWAGS航空磁测数据作为基准，对本次调查网格的基准面进行校正。