区域航磁异常汇编数据的长波成分提取、评价与替换技术  

Extraction,evaluation and replacement techniques of long wavelength components from compiled regional aeromagnetic anomaly data

作　　者：张攀 杜劲松[1,2,3] 王震 杨明豫 陈超 ZHANG Pan;DU JinSong;WANG Zhen;YANG MingYu;CHEN Chao(Institute of Geophysics and Geomatics,China University of Geosciences,Wuhan 430074,China;Hubei Subsurface Multi-scale Imaging Key Laboratory,Wuhan 430074,China;State Key Laboratory of Geological Processes and Mineral Resources,Wuhan 430074,China)

机构地区：[1]中国地质大学(武汉)地球物理与空间信息学院,武汉430074 [2]地球内部多尺度成像湖北省重点实验室,武汉430074 [3]地质过程与矿产资源国家重点实验室,武汉430074

出　　处：《地球物理学报》2022年第7期2595-2612,共18页Chinese Journal of Geophysics

基　　金：国家自然科学基金项目(42174090,41604060);地质过程与矿产资源国家重点实验室自主研究课题(#MSFGPMR01-5)资助。

摘　　要：各个国家与地区的航磁异常数据一般均采用多期磁测数据汇编而成,但是由于测量时间跨度较大、各期测量精度与校正参数不一致、以及磁力异常本身的时变性等原因,各期磁力异常数据之间具有系统差异,致使航磁异常汇编数据的长波成分可能存在不可靠性.本文基于二维修正球冠谐分析建模方法与单纯采用卫星磁测数据构建的全球岩石圈磁场模型可靠波段,提出区域航磁异常汇编数据的长波成分提取、评价与替换技术.通过仿真数据测试了本文所提方法的有效性之后,将其应用于澳大利亚第七版航磁异常网格数据,进而采用CM6模型的16~90阶球谐系数解算数据对提取的航磁异常长波成分进行了评价与替换,并通过空区补值与扩边处理,得到了澳大利亚及邻区完整的磁力异常网格数据.最后,采用替换了和未替换长波成分的航磁异常汇编数据,与CHAMP卫星磁测三分量数据联合进行修正球冠谐建模,结果显示,替换了长波成分的航磁异常汇编数据与卫星磁测数据融合效果更好,而由航磁异常汇编数据提取的长波成分与卫星磁测数据存在不相容性或非一致性.仿真测试与实际应用均表明本文所提方法具有可靠性和实用性,值得在区域航磁异常数据汇编中推广应用.The regional aeromagnetic anomaly data set and map of each country or district is usually produced by compiling the multi-survey data sets.However,because of the long surveying time span,inconsistency of the measuring accuracy and correcting parameters,and time-varying characteristics of the magnetic anomaly itself,there are systematic discrepancies among different aeromagnetic anomaly data sets,which possibly results in unreliability of long wavelength components of the compiled regional aeromagnetic anomaly data.To deal with this problem,the extraction,evaluation and replacement techniques of long wavelength components from regional aeromagnetic anomaly data is proposed in this paper.The magnetic field modelling method of two-dimensional revised spherical cap harmonic analysis(R-SCHA2 D)is adopted for extracting the long wavelength components.The reliable long wavelength components from the global lithospheric magnetic field model purely based on the satellite magnetic measurements are utilized to evaluate and replace the possibly unreliable long wavelength components from regional aeromagnetic anomaly data.After testing the validity by the synthetic observing data and the theoretical data,the method is practically applied to the grid data(7;version)of aeromagnetic anomaly over the Australia.Firstly,to improve the computational efficiency,the data is downscaled,padded by the EMM2017 model(16~790 degrees)in the data gaps,and smoothed.Secondly,the regional magnetic anomaly field model by the R-SCHA2 D is constructed based on the processed data.Thirdly,according to the wavelength relationship between the spherical harmonic(SH)degree and the R-SCHA2 D degree,the forward calculated data from SH coefficients(16~90 degrees)of CM6 model is then used to evaluate and replace the unreliable long wavelength components from regional aeromagnetic anomaly data.Then,the updated grid data of magnetic anomaly over the Australia and surroundings without data gaps is obtained.Finally,the compiled aeromagnetic anomaly data sets wit

关 键 词：航磁异常 数据汇编 岩石圈磁场 长波成分 二维修正球冠谐分析 

分 类 号：P318[天文地球—固体地球物理学]