National Gravity Compilation 2019 includes airborne tilt grid

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 tilt grid is derived from the 2019 Australian National Gravity Grids B series. These gravity data were acquired under the project No. 202008. The 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 totalling 345,000 line km and 106,000 line km of Airborne Gravity Gradiometry were used to generate this grid. 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. The grid shows the tilt filter of the complete Bouguer anomalies (B series) over Australia and its continental margins.重力数据用于测量因地球表面下方岩石密度变化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，以确保记录的响应仅源于地下岩石的影响。经处理后得到的数据集可用于解译，以揭示地下地质结构。经GA地球物理学家开展质量检查，以确保GA发布的最终数据符合使用要求。本次2019年国家重力汇编数据集包含源自2019年澳大利亚国家重力网格B系列的航空倾斜网格。该批重力数据采自编号为202008的项目。该网格的单元尺寸为0.00417度（约435米）。本重力异常网格源自截至2019年9月存储于澳大利亚国家重力数据库（Australian National Gravity Database, ANGD）中的地面观测数据，并补充了来自全球重力网格v28.1版的海洋数据；该全球重力网格的开发采用了美国斯克里普斯海洋研究所（Scripps Institution of Oceanography，加州大学圣迭戈分校）、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）提供的数据。此外，本数据集还纳入了航空重力与重力梯度测量数据，以提升地面重力数据质量欠佳区域的分辨率。在约180万条重力观测数据中，本网格的生成采用了ANGD内近140万个重力测点数据，以及总长度达34.5万千米的航空重力测量数据与10.6万千米的航空重力梯度测量数据。本网格所使用的地面重力数据采集自20世纪40年代至今，由澳大利亚联邦、各州及领地政府、矿业与勘探行业、高校及科研机构共同完成。测点间距范围约为11千米至不足1千米，澳大利亚大陆大部分区域的测点间距介于2.5千米至7千米之间。航空测量的测线间距介于0.5千米至2.5千米之间。重力地形校正的计算采用了海洋水深与陆上地形数据。本网格展示了澳大利亚及其大陆边缘区域的完整布格重力异常（B系列）倾斜滤波结果。