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摘要:
极光电激流是极区电流系的重要组成部分.本文利用CHAMP卫星10年的高精度标量磁场数据研究了极光电激流的地方时和季节变化特征，并对卫星与地面台站观测到的极光电激流进行了对比分析.结果表明，日侧极光电激流主要受太阳辐射的影响，而夜侧极光电激流主要受亚暴的影响.极光电激流具有明显的年、半年变化特征.夏季东向电激流和日侧西向电激流强于冬季，而夜间西向电激流冬季强于夏季.东向电激流和日侧的西向电激流在两至点增强，夜侧的西向电激流则在两分点增强.西向电激流与AL、SML指数有较好的相关性，东向电激流与SMU指数有较好的相关性，而与AU指数有一定差异，这与地磁台站的有效探测范围有关.
Abstract:The auroral electrojet is an important element of the polar current system. Based on ten years of high resolution scalar magnetic field data from CHAMP satellite, we studied the local time and seasonal variations of auroral electrojet. Furthermore, the auroral electrojet measured by satellite was compared with the auroral electrojet indices derived from the ground stations. It is shown that the daytime current is mainly controlled by the solar illumination, while the nighttime current is affected by the substorm. The auroral electrojet shows an obvious annual and semiannual variation. The eastward electrojet and the dayside westward electrojet are more intense in summer than in winter, while the nightside westward electrojet is more intense in winter than in summer. The eastward electrojet and the daytime westward electrojet is more intense at solstices, whereas the nighttime westward electrojet is more intense at equinoxes. The westward electrojet shows a good correlation with AL and SML indices. The eastward electrojet correlates well with the SMU index, but shows difference with the AU index. The discrepancy can be attributed to the fact that the peak eastward electrojet is located outside the detection range of the ground stations.
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Key words:
- Auroral electrojet /
- Auroral electrojet indices /
- Substorm /
- CHAMP
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图 4
(上图)极光电激流随季节和MLT的变化，(中图)极光电激流的年变化图，(下图)极光电激流的半年变化图
Figure 4.
(Top) Seasonal and MLT variations of the auroral electrojet. (Middle) Annual variations of the auroral electrojet. (Bottom) Semiannual variations of the auroral electrojet
图 5
北半球极光电激流与极光活动指数的季节和世界时分布
Figure 5.
Seasonal and universal time variations of auroral electrojet and auroral electrojet indices
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