DEM网格间距及校正半径对重力地形校正的影响  

Influence of DEM grid spacing and correction radius on terrain correction in gravity exploration

作　　者：张菲菲[1,2,3,4,5] 王万银 李倩[6] 王林[1,2,3] 马静 ZHANG Fei-Fei;WANG Wan-Yin;LI Qian;WANG Lin;MA Jing(Institute of Gravity and Magnetic Technology,Chang'an University,Xi'an 710054,China;School of Geology Engineering and Geomatics,Chang'an University,Xi'an 710054,China;Key Laboratory of Western China’s Mineral Resources and Geological Engineering Under Ministry of Education,Xi’an 710054,China;Key Laboratory of Gas Hydrate of Ministry of Natural Resources,Qingdao 266071,China;Qingdao Institute of Marine Geology,Qingdao 266071,China;Shanxi Provincial Institute of Geophysical and Geochemical Exploration,Yuncheng 044004,China;Key Laboratory of Marine Geology&Environment,CAS,Qingdao 266071,China;National Engineering Research Center of Offshore Oil and Gas Exploration,Beijing 100028,China)

机构地区：[1]长安大学重磁方法技术研究所,陕西西安710054 [2]长安大学地质工程与测绘学院,陕西西安710054 [3]西部矿产资源与地质工程教育部重点实验室,陕西西安710054 [4]自然资源部天然气水合物重点实验室,山东青岛266071 [5]青岛海洋地质研究所,山东青岛266071 [6]山西省地球物理化学勘查院,山西运城044004 [7]中国科学院海洋地质与环境重点实验室,山东青岛266071 [8]海洋油气勘探国家工程研究中心,北京100028

出　　处：《物探与化探》2023年第3期597-607,共11页Geophysical and Geochemical Exploration

基　　金：国家重点研发计划课题“航空地球物理综合处理解释方法研究及软件开发”(2017YFC0602202);山西省政府购买服务项目。

摘　　要：为消除地形质量对观测重力值的影响,在重力勘探中需要进行地形校正。由于地形距观测点最近,故其对重力值的影响最大;又由于地形起伏的复杂性,难以精准获得地形起伏的变化值。因此,地形校正成为影响重力勘探精度最关键的影响因素,其中地形数据的网格大小和地形校正的半径选择是影响地形校正计算精度的关键。本文收集了平原、丘陵和山地3种类型的5、10、25、50、100 m分辨率的DEM数据分别计算了不同网格间距、不同校正范围内的传统地形校正值和广义地形校正值,分析不同网格间距和校正半径对重力地形校正的影响。通过研究表明,大地水准面以上,地形质量对测点的重力影响主要集中在0~5 000 m环带范围内,约占整个地形质量影响值的90%,在丘陵和山地类型的地形校正过程中需要重视中、远区的校正,适当增加中区校正范围;不同类型地形对地形网格间距的需求不同,地形起伏变化越大,对DEM数据分辨率要求越高。根据对比结果的分析,对不同类型地形校正中DEM网格间距和校正半径的选取原则给出了相应的建议。该项工作为重力地形校正的理论研究及规范细化提供了重要参考,具有很好的推广应用前景。To remove the effect of terrain mass on observed gravity values,it is necessary to conduct terrain correction in gravity exploration.Terrains have the greatest impact on gravity values because they are the closest to observation points.However,the complex topographic relief makes it difficult to precisely determine the variation of topographic relief.Therefore,terrain correction is the most critical factor in the improvement of the precision of gravity exploration.The grid size of terrain data and the terrain correction radius are the key factors affecting the calculation precision of terrain correction.This study collected the DEM data with resolutions of 5 m,10 m,25 m,50 m,and 100 m for plains,hills,and mountains.Based on these data,this study calculated conventional and generalized terrain correction values under different grid spacings and correction ranges and analyzed the influence of different grid spacings and correction radii on terrain correction in gravity exploration.The results are as follows:the gravity effect of the terrain mass above the geoid on the observation points was mainly concentrated in the range of 0~5000 m and accounted for about 90%of the influence value of the total terrain mass.Attention should be paid to the correction of the middle and far areas during the terrain correction of hills and mountains,and it is necessary to appropriately increase the correction range of the middle areas;Different types of terrains had different requirements for grid spacings,and greater variations in topographic relief imposed higher requirements for the resolution DEM data.Based on the results of the comparative analysis,this study proposed some suggestions on the selection of DEM grid spacings and correction radii for different types of terrains.This study provides an important reference for the theoretical study and specification refinement of gravity terrain correction and has a great prospect for applications.

关 键 词：DEM数据 重力地形校正 网格间距 校正半径 

分 类 号：P631[天文地球—地质矿产勘探]