National Gravity Compilation 2019 includes airborne CSCBA 1VD image

Gravity data measure small changes in gravity due to changes in the density of rocks beneath the Earth's surface. The data collected 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 National Gravity Compilation 2019 includes airborne CSCBA 1VD image is a first vertical derivative of the complete spherical cap Bouguer anomaly grid for the 2019 Australian National Gravity Grids. These gravity data were acquired under the project No. 202008. The national grid has a cell size of 0.00417 degrees (approximately 435m). This gravity anomaly grid is derived from ground observations stored in the Australian National Gravity Database (ANGD) as at September 2019, supplemented with offshore data sourced from v28.1 of the Global Gravity grid developed using data from the Scripps Institution of Oceanography, the National Oceanic and Atmospheric Administration (NOAA), and National Geospatial-Intelligence Agency (NGA) at Scripps Institution of Oceanography, University of California San Diego. Airborne gravity and gravity gradiometry data were also included to provide better resolution to areas where ground gravity data was not of a suitable quality. Out of the approximately 1.8 million gravity observations, nearly 1.4 million gravity stations in the ANGD together with Airborne Gravity surveys totaling 345,000 line km and 106,000 line km of Airborne Gravity Gradiometry were used to generate this grid. The grid shows complete Bouguer anomalies over Australia and its continental margins. The ground gravity data used in this grid 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. Station spacing varies from approximately 11 km down to less than 1 km, with major parts of the continent having station spacing between 2.5 and 7 km. Airborne surveys have a line spacing ranging from 0.5 km to 2.5 km. Terrain corrections to gravity were calculated using both offshore bathymetry and onshore topography data. A first vertical derivative was calculated by applying a fast Fourier transform (FFT) process to the complete spherical cap Bouguer anomaly grid of the 2019 Australian National Gravity Grids to produce the grid shown on this image.

重力数据（Gravity data）用于测量因地球表层下方岩石密度变化所引发的微小重力变化。所采集的数据将通过标准流程进行处理，以确保记录到的响应仅由地下岩石所引起。经处理得到的数据集可通过解译，揭示地下的地质构造。经处理的数据会由GA地球物理学家开展质量核查，以确保GA发布的最终数据符合使用要求。
《2019年国家重力编目数据集》（National Gravity Compilation 2019）包含机载CSCBA 1VD影像，该影像是2019年澳大利亚国家重力网格（Australian National Gravity Grids）的完整球冠布格异常（spherical cap Bouguer anomaly）网格的一阶垂直导数。此类重力数据采集自项目编号202008的项目。该国家重力网格的单元格尺寸为0.00417度（约合435米）。本重力异常网格源自2019年9月时存储于澳大利亚国家重力数据库（Australian National Gravity Database, ANGD）的地面观测数据，并补充了源自全球重力网格v28.1版的近海数据；该全球重力网格由美国加州大学圣地亚哥分校斯克里普斯海洋研究所（Scripps Institution of Oceanography, University of California San Diego）基于斯克里普斯海洋研究所、美国国家海洋和大气管理局（National Oceanic and Atmospheric Administration, NOAA）以及美国国家地理空间情报局（National Geospatial-Intelligence Agency, NGA）的观测数据研发而成。为提升地面重力数据质量欠佳区域的分辨率，本次编目同时纳入了航空重力及重力梯度测量数据。本次网格生成共用到约180万条重力观测数据中的近140万个ANGD重力测点，以及总长34.5万千米的航空重力测量航线与10.6万千米的航空重力梯度测量航线。该网格展示了澳大利亚及其大陆边缘的完整布格异常分布。本网格所使用的地面重力数据，采集时段自20世纪40年代起直至今日，数据来源包括联邦政府、州及领地政府、采矿与勘探行业、高校及科研机构。测点间距范围约为11千米至不足1千米，澳大利亚大陆多数区域的测点间距介于2.5千米至7千米之间。航空测量的航线间距范围为0.5千米至2.5千米。重力数据的地形校正计算同时用到了近海水深数据与陆上地形数据。通过对2019年澳大利亚国家重力网格的完整球冠布格异常网格应用快速傅里叶变换（Fast Fourier Transform, FFT）流程，可计算得到一阶垂直导数，即本影像所展示的网格数据。