Seasonal variations of the ionospheric total electron content in Asian equatorial anomaly regions
Seasonal variations of the ionospheric total electron content in Asian equatorial anomaly regions
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DOI：
10.1029/2001ja001107
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发表时间：
2001-12
影响因子：
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通讯作者：
H. Tsai;Jann‐Yenq Liu;W. Tsai;Chao-Han Liu;C. Tseng;Chin-Chun Wu
中科院分区：
文献类型：
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作者：
H. Tsai;Jann‐Yenq Liu;W. Tsai;Chao-Han Liu;C. Tseng;Chin-Chun Wu
利用全球定位系统（GPS）观测了亚洲地区北方和南方赤道异常区的电离层总电子含量（TEC）。对1997年太阳活动极小期YMSM（25.2°N，121.6°E; 14.0°N地磁）和DGAR（7.3°S，72.4°E; 16.2°S地磁）站的TEC等值线图进行了分析。结果表明，电离层峰具有明显的季节变化。赤道北方和南距平峰上的TEC值在春秋两个月都有极大值，而冬季距平在南方没有出现。结果表明，两个峰在冬季的中午、春分的午后和夏季的傍晚前后充分发展，冬季两个峰明显向赤道方向移动，夏秋两季略有向极方向移动。这些现象可以用跨赤道中性风、日下点和极光向赤道风的组合理论来充分解释。
The ionospheric total electron contents (TEC) in both northern and southern equatorial anomaly regions are examined by using the Global Positioning System (GPS) in Asian area. The TEC contour charts obtained at YMSM (25.2°N, 121.6°E; 14.0°N geomagnetic) and DGAR (7.3°S, 72.4°E; 16.2°S geomagnetic) stations in 1997, solar minimum, are investigated. It is found that the ionospheric crests manifest remarkable seasonal variations. The TEC values on both northern and southern equatorial anomaly crests yield their maximum values during the vernal and autumnal months, but the winter anomaly does not appear in the southern region. Results show that both crests are fully developed around midday in winter, postnoon in equinoxes and late afternoon in summer, and the two crests move significantly equatorward in winter but slightly poleward in summer and autumn. These phenomena can be fully explained by a combined theory of the transequatorial netural wind, the subsolar point, and the auroral equatorward wind.