基于三维Taylor模型的福建及邻近地区地磁模型研究

基于福建及邻近地区高密度的256个地磁场矢量(D、I、H分量)实测数据,结合全球陆地1 km基准海拔高度工程的网格数据以及最新的第十二代国际地磁参考场模型(IGRF12),采用三维Taylor多项式模型构建了福建地区的地磁场模型.通过比较均方偏差(RMS)、磁场实际分布以及残差等,结果显示:(1) 当三维Taylor模型的截断阶数(N)为2时,可基本反映N为6时的二维Taylor模型的拟合效果;(2) 三维Taylor模型计算方便,精度较高,但较易出现龙格现象,因此在确定截断阶数时既要考虑模拟精度,还需要考虑边界效应问题.

Study of regional geomagnetic model of Fujian and adjacent areas based on 3D Taylor Polynomial model

Based on 256 measured geomagnetic vector data (Element D, I and H) in Fujian and adjacent areas, combined with the grid data of Global Land One-kilometer Base Elevation Project and the latest 12th International Geomagnetic Referenced Field (IGRF12) model, the regional geomagnetic model has been created by using three-dimensional (3D) Taylor Polynomial model. Through comparing the Root-Mean-Square error (RMS), geomagnetic distribution and residuals, two main conclusions are drawn: (1) Truncation degree N=2 of 3D Taylor model basically produce the same calculation result as truncation degree N=6 of 2D Taylor model; (2) 3D Taylor model can calculate conveniently and has high precision, but it also has the probability of producing Runge Phenomenon. So, both calculation precision and boundary effect problem should be considered when determining truncation degree.