第七代国际地磁参考场的检验与评价

EXAMINATION AND EVALUATION OF INTERNATIONAL GEOMAGNETIC FIELD FOR THE SEVENTH GENERATION

本文对国际地磁和高空物理学会推荐的第七代国际地磁参考场进行了检验和评价 .评价工作是通过 196 0～ 1995年 (5年间隔 )中国地磁台的观测数据 ;对中国地区复测点的测量数据 ;中国地区三阶泰乐多项式模型与第七代国际地磁参考场模型进行了比较 .求得了平均差和标准偏差 .并以 1990年代为例 ,做出了 1990年代各个地磁要素两个模型计算值之间的差值图 ,图上显示出这些差值的异常分布 ,这些异常是来自地壳源 .比较结果 ,可以得出结论 :第七代修正的国际地磁参考场地中国地区是适用的 .

The seventh-generation of International geomagnetic Reference Field(IGRF) recommended by the International association of Geomagnetism and Aeronomy(IAGA) has been examinated and evaluated in following aspects:The comparison was made annual means of magnetic obsevartories of China with IGRF derived geomagnetic Values;The repeat Stations data of geomagnetic elements measured over China areas and the values given by the IGRF were compared. The Taylor polynomial models of degree 3 of geomagnetic field over China (Called CH3D) and main field models of IGRF were compared:Mean differences and root mean sguare (RMS)deviation were obtained.as example for 1990 epoch,the maps of differences between the values computed from CH3D1990 and the corresponding DGRF 1990 values were constructed.The differences anomalies are associated with crources in the crust. Results of these comparisons show the IGRF-Seventh generation is a better geomagnetic references field for Chinese area.