中文摘要：

地磁场的标量位满足拉普拉斯方程．在球坐标系中，拉普拉斯方程的解可以写成球谐级数的形式．借助球谐分析的方法，地磁场可以被分为起源于地球内部的内源场和起源于地球外部的外源场．本文的内容主要包括：（1）阐述了利用球谐分析来反演Sq电流体系的方法．反演了1997年各月的Sq空间等效电流体系，并重点分析了南北半球Sq空间等效电流体系的位形和强度随季节的变化情况．（2）基于1997年的地磁观测数据建立各月静日期间中国地区地磁日变随纬度和AE指数变化的模型．将模型的计算结果与地磁台站的观测数据进行了对比分析．

英文摘要：

The scalar potential of the geomagnetic field satisfies the Laplace equation. The Laplace equation can be represented by the sum of spherical harmonics series in the spherical coordinates. By using the method of spherical harmonics analysis, the geomagnetic field can be divided into the inner source field and the outer source field. This paper mainly focuses on： （1） The spherical harmonics analysis method for the Sq current inversion that is used to inverse the Sq space equivalent current system in 1997. We intensively discuss the seasonal variations of Sq phase and magnitude. （2） We establish a geomagnetic diurnal model based on the observational geomagnetic field data in 1997, in which the geomagnetic field varies with latitude and AE index in China. Also, we compare the results from the model and the observations.