Characteristics of Seasonal Variation and Solar Activity Dependence of the Geomagnetic Solar Quiet Daily Variation
Characteristics of Seasonal Variation and Solar Activity Dependence of the Geomagnetic Solar Quiet Daily Variation
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DOI：
10.1002/2017ja024342
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发表时间：
2017-10
期刊：
影响因子：
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通讯作者：
A. Shinbori;Y. Koyama;M. Nosé;T. Hori;Y. Otsuka
中科院分区：
文献类型：
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作者：
A. Shinbori;Y. Koyama;M. Nosé;T. Hori;Y. Otsuka
利用1957-2016年1h时间分辨率的长期地磁场资料，研究了中纬度Memambetsu和赤道附近关岛地磁太阳静(Sq)日变化的X和Y分量的季节变化特征和太阳活动相关性。X分量和Y分量(Sq-X和Sq-Y)的月平均Sq变化表现出明显的季节变化和太阳活动相关性。季节变化的幅度在太阳活动高峰期显著增加，并与太阳F10.7指数成正比。太阳F10.7指数与Sq-X和Sq-Y的相关分析结果表明，它们之间几乎呈线性关系，但线性拟合线的斜率随当地时间和月份的变化而变化。这意味着Sq-X和Sq-Y对太阳活动的敏感性在不同的当地时间和季节是不同的。关岛Sq-Y的局地时间和季节变化与半球间场向流(FAC)产生的磁场有很好的一致性，FAC在黎明和黄昏部分从夏季到冬季流动，在正午到下午从冬季到夏季流动。黄昏星区的半球间FAC的方向与福岛模型的概念相反。
Characteristics of seasonal variation and solar activity dependence of the X and Y components of the geomagnetic solar quiet (Sq) daily variation at Memambetsu in midlatitudes and Guam near the equator have been investigated using long‐term geomagnetic field data with 1 h time resolution from 1957 to 2016. The monthly mean Sq variation in the X and Y components (Sq‐X and Sq‐Y) shows a clear seasonal variation and solar activity dependence. The amplitude of seasonal variation increases significantly during high solar activities and is proportional to the solar F10.7 index. The pattern of the seasonal variation is quite different between Sq‐X and Sq‐Y. The result of the correlation analysis between the solar F10.7 index and the Sq‐X and Sq‐Y shows an almost linear relationship, but the slope of the linear fitted line varies as a function of local time and month. This implies that the sensitivity of Sq‐X and Sq‐Y to the solar activity is different for different local times and seasons. The pattern of the local time and seasonal variations of Sq‐Y at Guam shows good agreement with that of a magnetic field produced by interhemispheric field‐aligned currents (FACs), which flow from the summer to winter hemispheres in the dawn and dusk sectors and from the winter to summer hemispheres in the prenoon to afternoon sectors. The direction of the interhemispheric FAC in the dusk sector is opposite to the concept of Fukushima's model.