最新全球重力数据库V23中陆域重力资料质量评估

Quality Evaluation of Land Gravity Data in the Latest Global Gravity Database V23

为了评估最新全球重力数据库V23中陆域重力资料的质量问题,选择了美国、秘鲁、爱尔兰、南非、肯尼亚、澳大利亚、中国等7个国家的8个区块约133万km2的重力数据进行对比分析。基于V23中自由空间重力异常数据,利用纯球坐标系内重力校正方法获得了这些区块的计算布格重力异常。利用相关分析的方法对这些区块的实测布格重力异常和计算布格重力异常进行相关分析,得到了相应的相关系数。通过对实测布格重力异常和计算布格重力异常之间相关系数及差值特征的综合分析,评估了全球重力数据库V23中选取的8个区块重力数据的质量。研究结果表明,斯克里普斯海洋研究所发布的最新全球重力数据库V23中陆域重力资料融合了大量测量年代较早的地面重力数据或者航空重力数据,而近十几年新完成的地面重力资料或者航空重力资料可能未融合进该数据库。具有大量年代较早的地面或者航空重力测量资料的区域,该数据库中陆域重力资料的质量较高,而重力工作程度较低的区域,其资料的质量则较低。

In order to evaluate the quality of the land gravity data in the latest global gravity database V23,the authors chose the gravity data of eight blocks with a total area of 1 330 000 km2 to compare and analyze,and these blocks involved seven countries,including the United States,Peru,Ireland,South Africa,Kenya,Australia,and China. Based on the free-air gravity anomaly data of the latest global gravity database V23,the authors obtained the calculated Bouguer gravity anomaly using the gravity correction methods within the pure spherical coordinate system in these eight blocks. Then,the correlation coefficients between the measured Bouguer gravity anomaly and the calculated Bouguer gravity anomaly were calculated by the correlation analysis method in these eight blocks. Finally,through comprehensive analysis of the features of these correlation coefficients and differences between the measured Bouguer gravity anomaly and the calculated Bouguer gravity anomaly in these eight blocks,the quality of the gravity data of these eight blocks was evaluated in the latest global gravity database V23. The results showed that the latest global gravity database V23,released by Scripps Institution of Oceanography,integrated a large number of the ground or airborne gravity data measuring in an earlier era,and the newly surveyed ground or airborne gravity data may not be integrated into the database. The quality of land gravity data is relatively high in the areas with a large number of older ground or airborne gravity data,otherwise it is low in the zones with a lower gravity working degrees.