Topside Ionospheric Conditions During the 7-8 September 2017 Geomagnetic Storm
Topside Ionospheric Conditions During the 7-8 September 2017 Geomagnetic Storm
复制标题
2017 年 9 月 7 日至 8 日地磁风暴期间的上部电离层状况
DOI：
10.1029/2019ja026590
复制
发表时间：
2019
影响因子：
2.8
通讯作者：
Dou Xiankang
中科院分区：
文献类型：
--
作者：
Jimoh Oluwaseyi;Lei Jiuhou;Zhong Jiahao;Owolabi Charles;Luan Xiaoli;Dou Xiankang
利用GRACE、SWARM‐A、TerraSAR‐X和MetOp‐A卫星的观测总电子含量（TECs）和SWARM‐A卫星的原位电子密度（Ne），研究了2017年9月7-8日地磁风暴期间的上层电离层状况。利用TEC和Ne的导数指数——TEC率指数（ROTI）和密度率指数（RODI）来表征上层电离层的不规则性。研究的主要结果如下：(1)在风暴第一主阶段，上望TEC明显增强。(2)在风暴恢复阶段，亚洲-澳大利亚地区的上望TEC在当地时间的早晚没有表现出异常的增强。(3)在中高纬度地区，TEC半球的不对称性在白天和夜间都很明显。(4)在此事件中，还检测到上层甲板TEC相对于风暴前条件的长时间恢复。(5)在风暴主要阶段，夜间ROTI在从赤道到两极的较宽纬度范围内呈增强趋势。(6)在9月7日相对较弱的地磁活动期间，与IMF - bz波动相关的电离层电场扰动可能在触发电离层异常方面发挥了非常重要的作用，这意味着电离层异常并不一定只在严重的地磁条件下发生。
The uplooking total electron contents (TECs) from the GRACE, SWARM‐A, TerraSAR‐X, and MetOp‐A satellites and in situ electron density (Ne) from SWARM‐A were utilized to investigate the topside ionospheric conditions during the 7–8 September 2017 geomagnetic storm. The rate of TEC index (ROTI) and rate of density index (RODI), which are derivative indices of TEC and Ne, respectively, were also used to characterize the topside ionospheric irregularities. The main results of this study are as follows: (1) There were significant enhancements seen in the uplooking TEC during the first main phase of the storm. (2) The uplooking TEC did not show unusual enhancement at the morning and evening local times in the Asian‐Australian sector during the recovery phase of the storm. (3) Prominent TEC hemispheric asymmetry at the middle and high latitudes was observed at both day and night sectors. (4) Long‐duration recovery of topside TEC with respect to the prestorm condition was also detected in this event. (5) Nighttime ROTI enhancements were presented in a wide latitudinal range from the equator to the poles during the main phases of the storm. (6) The ionospheric electric field disturbances associated with IMF‐Bzfluctuations probably played a very important role in triggering ionospheric irregularities during the relatively weak geomagnetic activity on 7 September, which implies that ionospheric irregularities do not necessarily occur under the severe geomagnetic conditions only.