Comprehensive analysis of the response of the ionospheric F2-layer to the largest geomagnetic storms from solar cycle #24 over Europe

<p>The complex analysis of the largest geomagnetic storms of solar cycle #24 maximum is our main aim in this study. Our focus is on the ionosphere, more precisely on the ionospheric F2-layer. The selected storm intervals are: 11-17 November 2012 (Kp_max=6.33, Dst_min=-108 nT ), 16-23 March 2013 (Kp_max= 6.67, Dst_min=-132 nT ),&#160; and 16-25 March 2015 (Kp_max=7.67, Dst_min=-228 nT). Data from 6 digisonde (DPS4D) stations, ground GNSS TEC and Swarm satellite constellation have been used for the investigation.</p><p>This study is the next step to validate our previous results discussed in <strong>Ber&#233;nyi et al. (2018)</strong>. We analyse the meridional behaviour of the geomagnetic disturbance caused ionospheric storms to understand and interpret the evolution of the caused effects.</p><p>The storm from 2012 is a no-positive phase (NPP) storm, but the 2013 and 2015 storms show the pattern of the regular positive phase (RPP) storm type (after the categorization by <strong>Mendillo and Narvaez, 2010</strong>). In all three cases a significant increase in electron density of the F2-layer can be observed at dawn/early morning (around 6:00 UT, 07:00 LT).&#160; We compared also the digisonde foF2 parameter with the GNSS TEC data. Besides, we observed the fade-out of the ionospheric layers at night during the geomagnetically disturbed time periods of storm 2012 and 2015. In order to determine whether this fade-out is connected to the L-shell location of the plasmapause we analysed the Swarm observations (for the storm 2015), too.</p><p>Ber&#233;nyi, K. A., Barta, V., & Kis. (2018). Midlatitude ionospheric F2-layer response to eruptive solar events-caused geomagnetic disturbances over Hungary during the maximum of the solar cycle 24: A case study. <em>Advances in Space Research</em>, <em>61</em>(5), 1230&#8211;1243. https://doi.org/10.1016/j.asr.2017.12.021</p><p>Mendillo, M., & Narvaez, C. (2010). Ionospheric storms at geophysically-equivalent sites - Part 2: Local time storm patterns for sub-auroral ionospheres. <em>Annales Geophysicae</em>, <em>28</em>(7), 1449&#8211;1462. https://doi.org/10.5194/angeo-28-1449-2010</p>