Isostatic Residual Gravity Anomaly Colour Composite Image of Onshore Australia 2016

This image is derived from gravity observations stored in the Australian National Gravity Database (ANGD) as at February 2016 as well as data from the 2013 New South Wales Riverina gravity survey. Out of the approximately 1.8 million gravity observations 1,371,998 gravity stations in the ANGD together with 19,558 stations from the Riverina survey were used to generate this image. The image shows isostatic residual gravity anomalies over onshore continental Australia. The data used in this image has been acquired by the Commonwealth, State and Territory Governments, the mining and exploration industry, universities and research organisations from the 1940's to the present day.
The isostatic corrections were based on the assumption that topographic loads are compensated at depth by crustal roots following the Airy-Heiskanen isostatic principle. A crustal density of 2670 kg/m3 was used for the isostatic correction, with an assumed density contrast between the crust and mantle of 400 kg/m3. An initial average depth to Moho at sea level of 37 km was used in the calculation. The isostatic corrections were then applied to the Complete Bouguer Gravity Anomaly Grid of Onshore Australia 2016 to produce the isostatic residual gravity anomaly grid.
The Isostatic Residual Gravity Anomaly Grid of Onshore Australia 2016 has been image enhanced and displayed as a hue-saturation-intensity (HSI) image with sun shading from the northeast to create this product.

本图像的数据源自2016年2月时收录于澳大利亚国家重力数据库（Australian National Gravity Database, ANGD）的重力观测资料，以及2013年新南威尔士州里弗赖纳重力勘测数据。在约180万条重力观测记录中，本图像生成时采用了ANGD内的1,371,998个重力测点，以及里弗赖纳勘测的19,558个测点。该图像展示了澳大利亚陆域大陆区域的均衡剩余重力异常。本图像所用数据采集自英联邦、各州及领地政府、矿业与勘探行业、高校及研究机构，时间跨度从1940年代直至今日。

本次均衡校正遵循艾里-海斯卡宁（Airy-Heiskanen）均衡原理，该原理假设地形载荷可通过深部的地壳根部实现补偿。校正过程中采用的地壳密度为2670 kg/m³，假定地壳与地幔间的密度差为400 kg/m³；计算初始时采用海平面处莫霍面的平均深度为37 km。随后将该均衡校正应用于《2016年澳大利亚陆域完整布格重力异常网格》，最终生成均衡剩余重力异常网格。

本产品通过对《2016年澳大利亚陆域均衡剩余重力异常网格》进行图像增强处理，并叠加东北向光照晕渲效果，将其渲染为色调-饱和度-明度（Hue-Saturation-Intensity, HSI）色彩空间图像后得到。