2004年11月强磁暴期间中国地区电离层TEC扰动特性分析

利用28个全球定位系统(Global Positioning System, GPS)观测站获取的电离层总电子含量(Total Electron Content, TEC)测量数据, 分析了2004年11月一次强磁暴期间的中国中低纬地区电离层TEC暴扰动特性, 结果表明:电离层TEC以正相暴扰动响应为主, 中纬地区的暴变扰动要强于低纬, 以北纬35°附近扰动最为强烈; 暴时电离层空间相关性变强, 电离层相关距离由宁静日的约5 500 km提升到暴变日的约8 000 km; 在8日的主暴扰动期间, 发现伴有自东北向西南的电离层TEC暴扰动传播, 自东向西的经向传播速度约为120 m/s, 要高于纬向传播.初步探讨表明, 向赤道中性风、日侧东向急剧穿透电场以及喷泉效应等可能是导致此次电离层TEC正相暴在北纬35°附近扰动最为强烈的关键因素, 也进一步揭示了电离层与太阳风、磁层之间以及电离层不同纬度区之间有着复杂的耦合过程.

Ionospheric TEC disturbances over China during the intense magnetic storm of November, 2004

Ionospheric total electron content(TEC) disturbance characteristics are obtained during a strong geomagnetic storm in November 2004 based on the TEC data from 28 GPS observation stations in China. It is shown that the responses of the ionospheric TEC are mainly positive phase disturbances with the most intensity in the vicinity of latitude 35°N. It is found that the spatial correlation of TEC becomes stronger on disturbed days than on quiet days, and the correlative distance increases from 5 500 km on November 2nd to 8 000 on November 8th. During the main phase of the storm on the 8th, an accompanied TEC disturbance spread from northeast to southwest, with a meridian velocity about 120m/s, much higher than that of the zonal speed. Preliminary study has shown that the neutral wind, the dayside eastward penetrating electric field and the fountain effect may be the key factors to cause this positive disturbance with the most intensity in the vicinity of latitude 35°N. It is also revealed the complex coupling processes among the ionosphere, the solar wind and the magnetosphere, and also among the different latitude zones of the ionosphere.