ANOMALOUS CHARACTERISTICS OF Sq IN EAST ASIA
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摘要: 使用IGY/IGC(1957.7.1-1959.12.30)期间全球地磁台网和中国长春、北京、上海、拉萨四台的地磁资料,分析了东亚大陆磁异常区地磁太阳静日变化Sq的异常特征。分析表明,组成Sq的两个主要谐波(1次和2次谐波)在东亚大陆异常区呈现出不同于其他区的分布特征:X分量振幅值一般高于地磁纬度相同的其他地区的振幅值。振幅极小值出现的纬度向南移动约20°,极小值的量值小于其他地区。由东亚异常区资料计算出的Sq外源电流体系强度与其他地区的强度相近,但电流涡焦点的地磁纬度比其他地区低10°左右。由于产生Sq变化的电离层发电机电流取决于地磁场和电离层电导率结构,而电离层电导率又与地磁场强度和位形有关,所以东亚大陆异常区Sq的异常表现可以归因于该区磁场结构对发电机过程的影响。数值计算表明,地磁轴的倾斜和东亚磁异常这两种因素的综合效应可以合理解释上述特征。本文的结果表明地磁场异常分布与空间电磁环境相关极为密切。Abstract: The magnetic records of the world station network during IGY/IGC with additional data at Changchun, Beijing, Shanghai and Lahsa of China have been used to study the characteristics of Sq in East Asia magnetic anomaly region. The results show that the principal harmonics (lst and 2nd harmonics) of Sq have special features different from those in other regions. The amplitudes of Xcomponent in the anomaly region are larger than those at other stations of similar latitude. The latitude of minimums amplitude is lower by 20° , and the minimum value is also smaller. The current intensity caculated on the basis of the data in East Asia region is similar to that from other regions data. However, the geomagnetic latitude of the current focus is lower by 10°. The Sq dynamo current depends on the earth's magnetic field and ionospheric conductivity structure, and the latter is affected by the magnetic field. Consequently, the above-mentioned features of Sq in East Asia region can be attributed to effects of magnetic field on ionospheric dynamo process.Numerial simulations show that the combined effects of the geomagnetic axis tiltand the magnetic anomaly in this region can explain these features of Sq. It is suggested from this study that the magnetic anomaly remarkably affects the electromagnetic environment of the near-earth space.
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