Seasonal and diurnal dependence of Pc 3‐5 magnetic pulsation power at geomagnetically conjugate stations in the auroral zones
Seasonal and diurnal dependence of Pc 3‐5 magnetic pulsation power at geomagnetically conjugate stations in the auroral zones
复制标题
极光区地磁共轭站 Pc 3-5 磁脉动功率的季节和昼夜依赖性
DOI：
10.1029/ja094ia06p06945
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发表时间：
1989
影响因子：
--
通讯作者：
T. Saemundsson
中科院分区：
文献类型：
--
作者：
Hiroaki Saito;N. Sato;Y. Tonegawa;T. Yoshino;T. Saemundsson
利用南极洲Syowa地磁共轭站和冰岛Husafell和Tjoernes地磁共轭站两年的地磁资料，研究了Pc 3-5磁脉动功率的季节和日变化。发现冬季半球站的磁脉动功率比夏季站的高。春分期间观测到的脉动显示出昼夜依赖性，即，冰岛地磁台上午的功率密度比昭和地磁台的高，下午则相反。共轭站之间的Pc 3脉动的功率密度比，这是与季节和当地时间，是高于Pc 5。这些特征可以归因于电离层中的阳光效应，即，当电磁波从磁层通过阳光照射的电离层传播到地面时，Pc 3-5脉动被屏蔽了。
Seasonal and diurnal variations of Pc 3-5 magnetic pulsation powers have been examined using 2 years of magnetic data from geomagnetically conjugate stations, Syowa in Antarctica and Husafell and Tjoernes in Iceland. The magnetic pulsation powers are found to be relatively higher at the winter hemisphere station than at the summer station. The pulsations observed during equinox show a diurnal dependence, i.e., that the power density is higher in the geomagnetic morning at the stations in Iceland than at Syowa, and this relationship is reversed in the afternoon. The power density ratio of Pc 3 pulsations between the conjugate stations, which is associated with the seasons and with local time, is higher than that of Pc 5. These characteristics can be attributed to the effects of sunlight in the ionosphere, i.e., Pc 3-5 pulsations are shielded when the waves propagate from the magnetosphere to the ground through the sunlit ionosphere.