Ionospheric and thermospheric response to the 27–28 February 2014 geomagnetic storm over north Africa
Ionospheric and thermospheric response to the 27–28 February 2014 geomagnetic storm over north Africa
复制标题
2014 年 2 月 27 日至 28 日北非上空地磁风暴的电离层和热层响应
DOI：
10.5194/angeo-2018-24
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发表时间：
2018
影响因子：
1.9
通讯作者：
M. Lazrek
中科院分区：
文献类型：
--
作者：
Khalifa Malki;A. Bounhir;Z. Benkhaldoun;J. Makela;N. Vilmer;D. J. Fisher;M. Kaab;Khaoula Elbouyahyaoui;B. Harding;Amine Laghriyeb;A. Daassou;M. Lazrek
抽象的。目前的工作探讨了电离层和热层对2014年2月27日至28日磁暴的响应。首次利用干涉仪、全天空成像仪和全球定位系统数据对北非的地磁暴进行了探测。这场风暴是由于2014年2月25日与太阳耀斑事件相关的日冕物质抛射（CME）冲击到达地球。位于摩洛哥的Oukaïmeden天文台（北纬31.206度，西经7.866度;磁纬22.84度）的法布里-珀罗干涉仪根据对630纳米红线发射的观测提供了对热层中性风的测量。广角成像系统记录630 nm发射的图像。这场磁暴对热层的影响从中性风明显偏离其季节性行为中可见一斑。在风暴期间，风在21：00至01：00 LT期间经历了强烈而陡峭的向赤道流动，并在22：00至03：00 LT期间经历了向西流动。赤道风速在22：00 LT时达到最大值120 m s−1，之后纬向风转向向西向。太平洋时间00：00后不久，风的纬向分量达到最大向西向风速80 m s−1。风的特征是典型的移动大气扰动（扰动）引起的环流;来自北方半球的第一个扰动在21：00 LT到达现场，来自南半球的第二个扰动在00：00 LT左右到达现场。我们估计北方电波的传播速度为550 m s-1。我们将风与DWM 07（扰动风模型）预测模型进行了比较，发现该模型很好地指示了风暴活动引起的新的环流模式，但在TADs内偏离很大。对电离层的影响也很明显，因为在观测到的赤道等离子体泡中，漂移方向发生逆转，从而使背景电动力学发生变化。安装在摩洛哥拉巴特（北纬33.998度，西经6.853度）的一个全球定位系统站的总电子含量测量结果显示，有一场正面风暴。
Abstract. The present work explores the ionospheric and thermospheric responses to the 27–28 February 2014 geomagnetic storm. For the first time, a geomagnetic storm is explored in north Africa using interferometer, all-sky imager and GPS data. This storm was due to the arrival at the Earth of the shock of a coronal mass ejection (CME) associated with the solar flare event on 25 February 2014. A Fabry–Perot interferometer located at the Oukaïmeden Observatory (31.206° N, 7.866° W; 22.84° N magnetic) in Morocco provides measurements of the thermospheric neutral winds based on observations of the 630 nm red line emission. A wide-angle imaging system records images of the 630 nm emission. The effects of this geomagnetic storm on the thermosphere are evident from the clear departure of the neutral winds from their seasonal behavior. During the storm, the winds experience an intense and steep equatorward flow from 21:00 to 01:00 LT and a westward flow from 22:00 to 03:00 LT. The equatorial wind speed reaches a maximum of 120 m s−1 for the meridional component at 22:00 LT, after the zonal wind reverses to the westward direction. Shortly after 00:00 LT a maximum westward speed of 80 m s−1 was achieved for the zonal component of the wind. The features of the winds are typical of traveling atmospheric disturbance (TAD)-induced circulation; the first TAD coming from the Northern Hemisphere reaches the site at 21:00 LT and a second one coming from the Southern Hemisphere reaches the site at about 00:00 LT. We estimate the propagation speed of the northern TAD to be 550 m s−1. We compared the winds to the DWM07 (Disturbance Wind Model) prediction model and find that this model gives a good indication of the new circulation pattern caused by storm activity, but deviates largely inside the TADs. The effects on the ionosphere were also evident through the change observed in the background electrodynamics from the reversal in the drift direction in an observed equatorial plasma bubble (EPB). Total electron content (TEC) measurements of a GPS station installed in Morocco, at Rabat (33.998° N, 6.853° W), revealed a positive storm.