Physics of auroral phenomena : proceedings of the 36th Annual seminar, Apatity, 26 February – 01 March, 2013 / [ed. board: A. G. Yahnin, A. A. Mochalov]. - Апатиты : Издательство Кольского научного центра РАН, 2013. - 215 с. : ил., табл.

GPS/TEC FLUCTUATIONS AT HIGH LATITUDE DURING GEOMAGNETIC STORM OF 11 OCTOBER 2010 “Physics o f Auroral Phenomena”, Proc. XXXVI Annual Seminar, Apatity, pp. 1 6 6 -1 6 9 , 2013 © Kola Science Centre, Russian Academy of Science, 2013 Polar Geophysical Institute I.I. Shagimuratov, 1.1. Efishov, Iu.V. Cherniak, N .Yu. Tepenitsyna and L.M . Koltunenko West Department o f IZMIRAN, Kaliningrad ' Russia 1. Introduction A trans-ionospheric radio wave propagating through electron density irregularities can caused phase and amplitude ionospheric fluctuations. The small irregularities with scale lees than 1 km lead to fast fluctuations it is usually called scintillations. The medium and large scale ionospheric irregularities are responsible for slow fluctuations. The low frequency GPS phase fluctuations occurred directly to electron density changes along the radio ray path or rapid total electron content (TEC) changes. Strong high latitude TEC fluctuations can complicate phase ambiguity resolution; increase the number of undetected and uncorrected cycle slips and loss o f signal lock in GPS navigation [Forte et al., 2004]. The aurora-induced ionosphere disturbances are supposed to be one o f the main sources of GPS faults in the Arctic and the Antarctic [Chernouss and Kalitenkov, 2011 ]. The information about TEC fluctuations can be obtained using of the regular GPS observations provided by the International GPS Service (IGS). The world wide and numerous networks of permanent GPS stations are very promising to monitor the spatial distribution of ionospheric irregularities in planetary scale [Shagimuratov et al, 2009]. In this report the GPS measurements of global IGS network were used to study the storm time occurrence of phase fluctuations (TEC changes) in the high latitude ionosphere during 11 October 2010 storm. 2. Solar and geomagnetic condition The considered in this study isolated geomagnetic storm October 11, 2010 was rather moderate. Active phase of the storm started on 11 October after 11 UT, maximal value of Kp was 4, Dst reached -80 nT. The satellite WIND registered sharp change of the solar wind parameters and the interplanetary geomagnetic field. , October 10-13, 2010 L oparskaya m ag n eto m eter 0 6 12 18 0 6 12 18 0 6 12 18 0 6 12 18 24 o-OO U n iv e r s a l T im e 6:00 12:00 18:00 U niversal T im e Fig. 1 Geomagnetic characteristics The variations Kp, Dst, Ae and IMF Bz component during 10-12 October are presented on the Fig.l (left panel). The storm-time variations of the geomagnetic field at Loparskaya station ( http://pgia.ru ) are demonstrated the right panel. At storm day the Bz component was positive before 09:30 UT and turned negative after with maximal values -13 nT, the Z component geomagnetic field at Laparskaya decrease after 12 UT and reached minimal value near 16 UT. 166