国际地磁参考场模型及其应用——以南海及其周边区域为例

International Geomagnetic Reference Field and Its application: Taking South China Sea and Its Surrounding Area as an Example

文章介绍最新的第12代国际地磁参考场(IGRF-12)模型,选取5个具有代表性的日期,应用该模型提取和计算1997—2017年全球地磁正常场值并绘制平面分布图,研究结果表明:全球地磁正常场的总体结构较稳定,IGRF模型具有可靠性。以南海及其周边区域为例,应用IGFR-12模型,采用数据统计、图形展示和时间域对比的综合分析方式,分析其在不同时间段内地磁正常场的分布特征和变化规律,研究结果表明:研究区地磁正常场值总体较低,变化较缓慢,呈增长趋势;地磁正常场总体北高南低且变化较大,同一纬度西高东低且变化较小;地磁正常场变化量由大到小的时间段依次为2012—2017年、2007—2012年、1997—2002年、2002—2007年,与IGRF-12中不同模型的差异相对应;IGRF模型中确定场模型数据的稳定性较优,预测场模型的可靠性较高但需进一步校正。

The IGRF-12 model was introduced in the paper,which was the newest version,while5 typical dates were selected and the global geomagnetic normal field values were extracted and calculated from 1997 to 2017 by using this model,and a plane distribution map was drawn.The research showed that the global geomagnetic normal field was stable and the IGRF model was reliable.Taking South China Sea and its surrounding area as an example,this paper used the IGRF-12 model to analyze the distribution characteristics and changes of the magnetic normal field of the study area in different time periods by the comprehensive analysis method of data statistics,graphic display and time domain contrast.The study showed that the geomagnetic normal field inthe study area was relatively low and the change was slow,showing an increasing trend;the geomagnetic normal field in the study area was generally higher in the north than in the south which had a wide gap,while higher in the west than in the east of the same latitude which had a little gap;the variation of geomagnetic normal field was different from 1997 to 2017,while the order of the date from the big to small was the year 2012 to 2017,2007 to 2012,1997 to 2002,2002 to2007,which corresponded to the difference in the IGRF-12;the stability of DGRF was better than that of the SV,which needed further correction.