Journal cover Journal topic
Annales Geophysicae Sun, Earth, planets, and planetary systems An interactive open-access journal of the European Geosciences Union
https://doi.org/10.5194/angeo-2018-24
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Regular paper
28 Mar 2018
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This discussion paper is a preprint. It is a manuscript under review for the journal Annales Geophysicae (ANGEO).
Ionospheric and thermospheric response to the 27–28 February 2014 geomagnetic storm
Khalifa Malki1, Aziza Bounhir1, Zouhair Benkhaldoun1, Jonathan J. Makela2, Nicole Vilmer3, Daniel J. Fisher2, Mohamed Kaab1, Khaoula Elbouyahyaoui1, Brian J. Harding2, Amine Laghriyeb1, Ahmed Daassou1, and Mohamed Lazrek1 1Oukaimeden Observatory, High Energy Physics and Astrophysics Laboratory, FSSM, Cadi Ayyad University, Marrakesh BP: 2390, Morocco
2Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
3LESIA, Observatoire de Paris, 5 Place Janssen, 92195-Meudon CEDEX, France
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 caused by coronal mass ejection (CME) associated flares that occurred on 25 February 2014. A Fabry-Perot interferometer located at the Oukaimeden Observatory (31.206° N, 7.866° W, 22.84° N magnetic) in Morocco provides measurements of the thermospheric neutral winds based on the observations of the 630 nm redline 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 to 01 LT and a westward flow from 22 to 03 LT. The equatorial wind speed reaches a maximum of 120 m/s for the meridional component at 22 LT, when the zonal wind reverses to the westward direction. Shortly after 00 LT a maximum westward speed of 80 m/s was achieved for the zonal component of the wind. The features of the winds are typical of TAD (Traveling Atmospheric Disturbances) induced circulation; the first TAD coming from the northern hemisphere reaches the site at 21 LT and a second one coming from the southern hemisphere reaches the site at about 00 LT. We estimate the propagation speed of the northern TAD to be 550 m/s. We compared the winds to 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 drift direction in an observed equatorial plasma bubble. TEC measurements of a GPS station installed in Morocco, at Rabat (33.998° N; 6.853° W, geographic) revealed a positive storm.
Citation: Malki, K., Bounhir, A., Benkhaldoun, Z., Makela, J. J., Vilmer, N., Fisher, D. J., Kaab, M., Elbouyahyaoui, K., Harding, B. J., Laghriyeb, A., Daassou, A., and Lazrek, M.: Ionospheric and thermospheric response to the 27–28 February 2014 geomagnetic storm, Ann. Geophys. Discuss., https://doi.org/10.5194/angeo-2018-24, in review, 2018.
Khalifa Malki et al.
Khalifa Malki et al.
Khalifa Malki et al.

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Short summary
The novelty of this paper resides in the fact that it addresses the termosphere/ionosphere coupling in a mid-latitude site in north Africa. We have used Fabry-Perot measurements of the thermospheric winds and wide-angle camera detection of ionospheric structurers, at an altitude of about 250 km. We have also used GPS data to extract the TEC over the studied area. We have focused our study on the 27 Feb geomagnetic storm.
The novelty of this paper resides in the fact that it addresses the termosphere/ionosphere...
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