非偶极子磁场西向漂移的频散特征

Dispersion of the westward drift rate in the non-dipole geomagnetic field

根据第8代国际参考地磁场的资料,本文采用Briggs方法对1900～2000年期间m=1～10次谐波的磁位的全球平均西向漂移速度进行了计算和分析,得出了与Hide的理论预测完全不同的频散特征,即地磁场西向漂移呈现出负频散特征.本文还就Briggs方法得到的结果与采用Malin纬度剖面法的结果进行了比较和讨论,结果表明,正是由于非偶极子磁场的某些谐波分量及其漂移速度的全球分布存在着纬度依赖性,导致了两种方法计算出的个别谐波的漂移速度存在着较大的差异.

Based on the 8th generation of International Geomagnetic Reference Field, the global average westward drift rates of geomagnetic potential harmonic W1 - W10 during 1900 - 2000 are studied by using the Briggs＇ method. The results show that the westward drift rate decreases with the increasing harmonic order rn, that doesn＇t agree with the Hide＇ s theoretical prediction. Two different analysis methods as used by Malin and Briggs respectively are discussed, It is suggested that the latitudinal dependence of the nondipole field drift could be different results by using different analysis methods.