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本文利用1975年我国地区基本磁场和长期变化的资料,以及我国四个地磁台1970—1980年的年均值,检验全球范围地磁场的球谐模式,这些模式是 AWC_(75),IGS_(75),IGRF_(75)和 BBM_(80),就基本磁场模式而论,IGRF,AWC和 IGS 与我国地磁场的分布均有较大的偏差,但相对而言,AWC 和 IGS 对我国地区地磁场的拟合效果比 IGRF要好。对于长期变化模式,上述三个模式与我国地磁场的长期变化也有一定的偏差,其中,总强度和垂直强度的偏差可达近20nT/年;这三个1975年的模式均能较好地表示我国七十年代初期地磁场的长期变化,但不能较好地表示七十年代后期的长期变化;BBM_(80)能较好地表示七十年代后期磁偏角和垂直强度的长期变化。文章还讨论了关于建立全球和局部地区地磁场及其长期变化模式的几个问题。
In this paper, we use the data of basic magnetic field and long-term change in China in 1975 and the annual average of four geomagnetic stations in China from 1970 to 1980 to test the spherical harmonic modes of the global magnetic field. These modes are AWC_ (75), IGS_ (75) , IGRF_ (75) and BBM_ (80). As far as the basic magnetic field model is concerned, the distribution of IGRF, AWC and IGS is greatly deviated from the distribution of geomagnetic field in our country. However, Fitting better than IGRF. For the long-term variation model, the above three models also have a certain deviation from the long-term variation of the geomagnetic field in China, in which the deviation of the total intensity and the vertical intensity can reach nearly 20 nT / year; all of the three 1975 models can well represent The long-term changes of the geomagnetic field in the early seventies of our country can not well represent the long-term changes in the late seventies. BBM_ (80) can better represent the long-term changes of the declination and the vertical intensities in the late seventies. The article also discussed several issues related to the establishment of global and local geomagnetic fields and their long-term patterns of change.