基于IGRF-13的海洋磁力异常重计算与精度分析

Recalculation and accuracy analysis of marine magnetic mnomalies based on IGRF-13

研究分析了最新的国际地磁参考场模型IGRF-13的数据来源及模型特征,并与以往模型进行了精度对比。在此基础上,结合不同时期获取的海洋磁力数据融合的实际需求,制定了海洋磁力正常场校正方法及磁力异常重计算流程。选取了南海试验区和太平洋试验区的调查数据,应用最新国际地磁参考场IGRF-13对其进行了正常场校正和磁力异常重计算,得出以下结论:(1)磁力正常场模型IGRF-13包含1900-2025年的26个磁力模型,可采用该模型对以往不同时期获取的磁力数据进行统一重计算;(2)应用最新IGRF-13对南海、太平洋试验区的磁力异常数据进行重计算后,数据内符合精度提升了0.05~0.20 nT;(3)建议在对不同年代的地磁数据融合应用前,先消除时变效应。本文提出的地磁正常场校正方法适用于减弱长期变化磁场的时变效应影响,提升磁力成果数据精度。

The data sources and model characteristics of IGRF-13,the latest international geomagnetic reference field model are analyzed.The accuracy of IGRF-13 is compared with that of previous models.Then,the correction method of marine magnetic normal field and the recalculation flow chart of magnetic anomaly are proposed according to the actual needs of magnetic data fusion.Using the latest international geomagnetic reference field IGRF-13,the normal field correction and magnetic anomaly recalculation are carried out.The conclusions are as follows:(1)IGRF-13 contains 26 magnetic models from 1900 to 2025,which can be used for unified recalculation of magnetic data obtained in different periods.(2)When the latest IGRF is used to recalculate the magnetic anomaly data of the South China Sea and the Pacific Ocean,the accuracy of the data is improved by 0.05~0.20 nT.(3)It is recommended that the time-varying effect to be eliminated before the fusion application of geomagnetic data from different ages.The geomagnetic normal field correction method proposed in this paper is suitable for reducing the time-varying effect of long-term changing to improve the accuracy of the magnetic results data.