North‐south components of the annual asymmetry in the ionosphere
North‐south components of the annual asymmetry in the ionosphere
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DOI：
10.1002/2014rs005401
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发表时间：
2014-07
期刊：
影响因子：
1.6
通讯作者：
T. Gulyaeva;F. Arıkan;M. Hernández‐Pajares;I. Veselovsky
中科院分区：
文献类型：
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作者：
T. Gulyaeva;F. Arıkan;M. Hernández‐Pajares;I. Veselovsky
利用南、北磁半球不同的地球空间参数，对至日期间电离层的不对称性进行了回顾性研究。根据全球电离层地图生成的总电子含量（TEC）和全球电子含量（GEC）数据，1999-2013年的GIM-TEC，2001-2012年TOPEX-Jason 1和2号卫星测量的电离层电子含量（IEC），1969-1982年期间ISIS 1、ISIS 2和IK 19卫星上测量的F2层临界频率和峰高，分析了1999-2013年5级以上地震的发生情况。GEC和IEC在观察年份观察到年度不对称性，不对称指数AI显示1月> 7月超过0.02至0.25。结果表明：1 ~ 7月TEC和IEC在太平洋磁经270° ± 5°E范围内的不对称性随当地时间和磁纬的变化规律一致。F2层峰值电子密度NmF 2和峰值高度hmF 2的海/陆差异（用顶部探测数据收集）表明，电离层沿着海岸倾斜，在海上更高的峰值高度处电子密度更高。顶侧峰值电子密度NmF 2、TEC、IEC和GEC的半球部分在南半球占主导地位，这类似于南磁半球以地震为主的地震活动模式。虽然这项研究是针对电离层至点期间的半球和年度不对称性进行的，但结论似乎适用于地震-电离层关联的其他方面，其中构造板块边界代表了空间天气风险增强的区域。
A retrospective study of the asymmetry in the ionosphere during the solstices is made using the different geospace parameters in the North and South magnetic hemispheres. Data of total electron content (TEC) and global electron content (GEC) produced from global ionospheric maps, GIM‐TEC for 1999–2013, the ionospheric electron content (IEC) measured by TOPEX‐Jason 1 and 2 satellites for 2001–2012, the F2 layer critical frequency and peak height measured on board ISIS 1, ISIS 2, and IK19 satellites during 1969–1982, and the earthquakes M5+ occurrences for 1999–2013 are analyzed. Annual asymmetry is observed with GEC and IEC for the years of observation with asymmetry index, AI, showing January > July excess from 0.02 to 0.25. The coincident pattern of January‐to‐July asymmetry ratio of TEC and IEC colocated along the magnetic longitude sector of 270° ± 5°E in the Pacific Ocean is obtained varying with local time and magnetic latitude. The sea/land differences in the F2 layer peak electron density, NmF2, and the peak height, hmF2, gathered with topside sounding data exhibit tilted ionosphere along the seashores with denser electron population at greater peak heights over the sea. The topside peak electron density NmF2, TEC, IEC, and the hemisphere part of GEC are dominant in the South hemisphere which resembles the pattern for seismic activity with dominant earthquake occurrence in the South magnetic hemisphere. Though the study is made for the hemispheric and annual asymmetry during solstices in the ionosphere, the conclusions seem valid for other aspects of seismic‐ionospheric associations with tectonic plate boundaries representing zones of enhanced risk for space weather.