Data fitting and modeling of regional geomagnetic field
Data fitting and modeling of regional geomagnetic field
复制标题
区域地磁场数据拟合与建模
DOI：
10.1007/s11770-015-0500-6
复制
发表时间：
2015
影响因子：
0.7
通讯作者：
Jiang Yong
中科院分区：
文献类型：
--
作者：
Feng Yan;Sun Han;Jiang Yong
在基于数据拟合的区域地磁场模型中，截断水平(TL)的选择和边界效应(BE)的控制是至关重要的。我们结合泰勒和勒让德多项式来模拟大陆中国1960年、1970年、1990年和2000年的地磁数据。为了解决TL和BE问题，我们首先通过计算模型的均方根误差(RMSE)来确定TL的范围。接下来，我们使用Akaike信息准则(AIC)和归一化均方根误差(NRMSE)来确定最优TL。利用区域异常相加(RAA)和均匀相加(UA)方法在国境线外添加补充点，发现极值点的强度逐渐减小并趋于稳定。相对于中国，UA方法更好地控制BES，而RAA方法在较小的尺度上做得更好。综上所述，我们依靠三步法来确定最佳TL，并提出了确定最佳补充点数目的标准。
The selection of the truncation level (TL) and the control of boundary effect (BE) are critical in regional geomagnetic field models that are based on data fitting. We combine Taylor and Legendre polynomials to model geomagnetic data over mainland China for years 1960, 1970, 1990, and 2000. To tackle the TL and BE problems, we first determine the range of TL by calculating the root-mean-square error (RMSE) of the models. Next, we determine the optimum TL using the Akaike information criterion (AIC) and the normalized rootmean- square error (NRMSE). We use the regional anomaly addition (RAA) and the uniform addition (UA) method to add supplementary point outside the national boundary, and find that the intensities of extreme points gradually decrease and stabilize. The UA method better controls BEs over China, whereas the RAA method does a better job at smaller scales. In summary, we rely on a three-step method to determine the optimum TL and propose criteria to determine the optimum number of supplementary points.