National Gravity Compilation 2019 DGIR 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 DGIR grid is produced from the 2019 Australian National Gravity Grids A series. These gravity data were acquired under the project No. 202008. The grid has a cell size of 0.00417 degrees (approximately 435m). The data are given in units of um/s^2, also known as 'gravity units', or gu. The data are derived from ground observations stored in the Australian National Gravity Database (ANGD) as at September 2019, supplemented by 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. Out of the approximately 1.8 million gravity observations, nearly 1.4 million gravity stations in the ANGD together with marine data 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 for ground observations 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. The grid shows de-trended global isostatic residual anomalies (A series) over Australia and its continental margins. This National Gravity Compilation 2019 DGIR grid (DGIR) was obtained by subtracting 3 quantities (i.e., the near-field isostatic correction, the far-field isostatic correction, and a first order trend correction) from Complete Bouguer Anomaly data (CBA) of the 2019 Australian National Gravity Grids A series.重力数据用于测量因地球表层下方岩石密度变化引发的微小重力场变化。所采集的数据将通过标准流程进行处理，以确保记录得到的响应仅源于地下岩石的影响。经处理后得到的数据集可通过解译，揭示地下地质构造特征。经处理的数据将由GA地球物理学家开展质量核验，确保GA发布的最终数据符合使用要求。本次发布的2019年国家重力编绘DGIR格网数据源自2019年澳大利亚国家重力格网A系列数据集。该批重力数据采集自项目编号为202008的项目。该格网的单元尺寸为0.00417度（约合435米）。数据单位为微米每二次方秒（μm/s²，原文标注为um/s²），又称重力单位，缩写为gu。本数据集源自截至2019年9月存储于澳大利亚国家重力数据库（ANGD）的地面观测数据，并补充了由全球重力格网v28.1版本提取的近海数据；该全球重力格网的构建数据来自斯克里普斯海洋研究所、美国国家海洋和大气管理局（NOAA）以及美国国家地理空间情报局（NGA），相关数据由加州大学圣地亚哥分校斯克里普斯海洋研究所提供。本次格网构建共使用了约180万条重力观测数据中的140万条ANGD地面重力站数据，以及全部海洋观测数据。本格网使用的地面重力数据采集时间跨度自20世纪40年代至今，数据提供方包括联邦政府、州及领地政府、矿业与勘探行业、高校及科研机构。地面观测的测站间距范围约为11千米至不足1千米，澳大利亚大陆大部分区域的测站间距介于2.5千米至7千米之间。该格网展示了澳大利亚及其大陆边缘区域的去趋势全球均衡剩余异常（A系列）数据。本次2019年国家重力编绘DGIR格网数据的生成方式为：从2019年澳大利亚国家重力格网A系列的完全布格异常（CBA）数据中，扣除近场均衡校正量、远场均衡校正量以及一阶趋势校正量这三项参数。