中国地区地磁长期变化研究

采用2000~2004年中国地区34个台站的地磁日均值数据, 计算了通日和静日的平均年变率,以及静日的拟合年变率.应用上述年变率, 建立了2000.0~2005.0年代中国地区地磁场长期变化泰勒多项式模型和曲面样条模型.分析讨论了该泰勒多项式模型和曲面样条模型与国际地磁参考场长期变化模型(IGRF-SV)的异同, 结果表明,中国地区地磁长期变化的泰勒多项式模型与曲面样条模型的形态与数值是一致的,而且与IGRF-SV长期变化的趋势也是一致的,但中国地区地磁长期变化具有区域特征.

Study of geomagnetic secular variation in China

Using the data of the geomagnetic diurnal means during 2000~2004 at 34 observatories in China, we calculated the mean annual change rates on the quiet days and all days, and the fitting annual change rates on the quiet days. The Taylor polynomial model and the spline model of the geomagnetic secular variation in China for epoch 2000.0~2005.0 were established, based on the above annual change rates. The similarity and difference between the Taylor polynomial model, the spline model and the secular variation model of International Geomagnetic Reference Field (IGRF-SV) were analyzed and discussed. The results show that the shape and the value of the Taylor polynomial model and the spline model for the geomagnetic secular variation in China are quite consistent, and their long-term trends are also consistent with IGRF-SV. However, the geomagnetic secular variation in China has some regional characteristics.