【摘要】 通过分析１９００年以来每５ａ地球磁场各阶球谐系数的相关系数发现，地球磁场偶极子分量的ρ值在１９０５-１９７０年基本保持不变，１９７０-１９８５年下降，１９８５-１９９５年又上升，呈Ｖ字型变化。而非偶极子分量的　值则具有周期性变化，在１９１５年、１９４５年和１９８０年出现峰值，在１９３５年和１９６５年则处于低谷，变化周期约为３０ａ。通过分析地球磁场非偶极子分量　值周期变化与日长周期变化的相关性，得出两点新的认识：１．非偶极子分量的周期性变化与核幔边界耦合过程相关，而偶极子分量的变化对应外核的深部过程；２．外核顶部流体具有周期性的变化，其变化周期与日长及非偶极子分量的变化周期一致。更多还原

【Abstract】 The correlation function of different components of geomagnetic field showsthat of dipole part keeps nearly unchanged from 1905-1970y, drops a little from1970-1985y, then goes up from 1985-1995y. While the of non-dipole components,which has three wave crests (1915y, 1945y, and 1980y) and two troughs (1935y and1965y), changes with period about 30y. Compared the variations in and the timerate of change of length of day ( ), we put forward: (1) the periodical change ofgeomagnetic non-dipole is related to the core-mantle coupling, while the dipolecomponent is controlled by the process of the deeper outer-core; (2) the fluid motionof upper outer-core changes periodically with the same period of .更多还原