Barta, Veronika

Mushtak, Vadim

Price, Colin

Sátori, Gabriella

Williams, Earle R.

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Geophysical Research AbstractsVol. 16, EGU2014-8790, 2014EGU General Assembly 2014© Author(s) 2014. CC Attribution 3.0 License.Variations of Schumann resonance frequencies at the extraordinary solaractivity of October/November 2003Gabriella Satori (1), Vadim Mushtak (2), Earl e Williams (2), Colin Price (3), and Veronika Barta (1)(1) Research Centre for Astronomy and Earth Sciences, HAS, Geodetic and Geophysical Institute, Sopron, Hungary(gsatori@ggki.hu, +3699508355), (2) Massachusetts Institute of Technology, Parsons Laboratory, Cambridge, MA, USA, (3)Department of Geophysical, Atmospheric and Planetary Sciences, Tel Aviv University, IsraelThe upper boundary of the Earth-ionosphere cavity is the ionospheric D-region. The upper part of thisregion is ionized by the solar UV, EUV, Lyman-α (121.6 nm) and Lyman-β (102.6 nm) as well as the soft (1-10 nm) and hard (<1 nm) X-ray in the sunlit site of the cavity. In the lower part of the D-region, the galacticcosmic rays are responsible for the ionization. A series of dramatic solar activity events occurred in Octoberand November of 2003. The hard solar X-ray flux increased by more than two orders of magnitude alreadyin October 18 and lasted until November 4 while the 10.7 cm radio flux indicating the 2-3 fold variations ofEUV radiation maximized only in October 28. The time evolution of the disturbances of these two ionizationsources was quite different. At the end of October and the beginning of November 2003 two active regionsproduced a series of extremely energetic solar eruptions. In connection with the flare on October 28, 2003,a coronal mass ejection was emitted at a high speed directly towards the Earth and caused a dramaticForbush decrease. The effects of these events have been studied by Schumann resonance (SR) parametersmeasured at Nagycenk, Hungary and in Mitzpe Ramon, Israel. SR frequency increased simultaneously withthe increase of the hard solar X-ray flux in October 18, 2003 and followed it in case of the 1st and 2nd Ezmodes both at Nagycenk and in Mitzpe Ramon until November 4, 2003. Neither the increased EUV radiationwith maximum at October 28, 2003 and nor the huge Forbush-decrease between October 28 and November4, 2003 left any signature on SR frequencies. This result supports that the hard solar X-ray has an importantrole in conditioning the Earth-ionosphere cavity at the heights of ∼ 90km -100 km as shown on the 11-yearsolar cycle and during short solar X-ray bursts (Sátori et al., 2005).

Variations of Schumann resonance frequencies at the extraordinary solar activity of October/November 2003

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