2018-08-25~29期间全球电离层TEC对地磁暴的响应分析

使用IGS提供的全球电离层地图对2018-08-26地磁暴期间TEC变化进行分析，利用滑动四分位距法提取全球TEC扰动特征，并初步探讨此次磁暴引起的电离层扰动响应机制。结果表明：1）磁暴主相期间，除北极地区外电离层TEC主要表现为正相扰动；在恢复相期间，电离层TEC在北半球呈现长期负扰，而在南半球则相反。2）磁暴期间全球电离层TEC扰动与热层成分O/N₂变化有关。星际磁场南向期间，东向快速穿透电场对全球日间电离层TEC正扰具有很大影响，高能粒子的沉降作用可能是高纬和极区TEC发生正扰的原因；夏冬季节环流会促进电离层在磁暴恢复相阶段的南北不对称响应。

Response Analysis of Global Ionospheric TEC to Geomagnetic Storms from August 25~29, 2018

We use the global ionospheric maps(GIMs) provided by international GNSS service(IGS) to analyze the total electron content(TEC) changes during the storm on August 26, 2018. We use the sliding interquartile rang method to extract the disturbance characteristics of the global TEC, and discuss the response mechanism of the ionospheric disturbance caused by this storm. The results show: 1)The ionospheric TEC is a mainly positive disturbance except in the Arctic region during the main phase of the storm. TEC shows a long-term negative disturbance in the northern hemisphere during the recovery phase, but it is opposite in the southern hemisphere. 2) The ionospheric TEC disturbance caused by the storm is related to the change of thermosphere O/N₂ ratio. The eastward prompt penetration electric field(PPEF) has a great influence on the global daytime ionospheric TEC positive disturbance during the period when the Bz component of interplanetary magnetic field is southward; the sedimentation of high energy particles may be the cause of the positive disturbance of TEC in high latitude and polar regions. The seasonal circulation between summer and winter promotes the north-south asymmetric response of global ionospheric TEC during the recovery phase of the storm.