Physics of auroral phenomena : proceedings of the 38th annual seminar, Apatity, 2-6 march, 2015 / [ed. board: A. G. Yahnin, N. V. Semenova]. - Апатиты : Издательство Кольского научного центра РАН, 2015. - 189 с. : ил., табл.

Occurrence o f GPS signals phasefluctuations during auroral activity observations with 30 sec sampling interval provide information about occurrence of ionospheric irregularities with size more than 1 0 km. As a measure of fluctuation activity the rate of TEC (ROT, in the unit of TECU/min, 1 TECU=10 16 electron/m2) at 1min. interval was used [7]. As measure intensity fluctuations index ROTI was used [ 8 ]. r o t i = A /( r o t 2) - ( r o t )2 Results 3.1 Comparison of TEC fluctuation data during weak and strong geomagnetic activity The temporal occurrence of the TEC fluctuations is clearly observed in time variations of the dual frequency carrier phase along satellite passes. For example, the TEC variations, observed at midlatitude stations Kaliningrad for quiet and disturbed conditions, are presented at Fig. 2. The picture demonstrates the rates of TEC changes (ROT) along all Figure 2. Development of TEC fluctuations at midlatitude Kaliningrad station for quiet (1 October) and disturbed (2 October) days For quiet day the fluctuations were very low. During geomagnetic disturbed day the intensity of fluctuations was detected in satellite pass of PRN 14 around 05 UT. Detaille picture fluctuations for PRN 14 for quiet and disturbed days is presented in Fig. 3. The satellite trajectory in the ionosphere (cross line) also shown on the picture. 8 9 10 11 12 13 8 9 10 11 12 13 8 - : i longitude 00 с сс . 1 1 1 1 1 longitude 4 - 4 - U • + + + + f ~1------------------------------------------------------------------- 1— RO T 0 1 i atitude - 5 5 § 0 - 1 i f V atitude _4_ - 4 - + ч ................ - 8 - 1 1 1 i 1 | i 1 1 1 1 ' | 1 1 1 11'"1 - 5 0 - 8 - - “ I—т—r "1 " I j 1 1 ! : 1 1 1 i I J 5 6 7 8 5 6 7 8 U T (hours) U T (hours) Figure 3. Development of TEC fluctuations at midlatitude Kaliningrad station for quiet and disturbed days The intensive TEC fluctuations during storm day was localized at latitudes 57-58°N when magnetic bays were occurred on magnetogram of the Scandinavian network in time interval 05-06 UT (Fig. 4.). Obviously, the time course of. these effects coincide, moreover, the time course of events in both diagrams coincide with the temporal variations parameter ROT at Tromso and Kaliningrad stations together with records of spectral and temporal variations of the geomagnetic field at the stations Lovozero and Sodaynkyula shown in Fig. 5. It appears that bear upon the maximum variations, as well as the pulsations of the geomagnetic field, we can determine the source which affect a destruction of the navigation signal in the ionosphere in the presence of auroral disturbances. This is particularly noticeable in the intervals substorm intensification of disturbances. For example, a small perturbation around 01.10.2013 21:00 UT, localized exclusively in the polar region, had little effect on variations of ROT in Kaliningrad. At the same time, strong disturbance about 02/10/2013 05:00 UT as reflected in magnetic observations at the latitude of Kaliningrad and in the values of ROT on this point. This correspondence suggests the possibility of diagnostics and prognosis of the state of the reception of navigation signals from measurements of geomagnetic field variations. 108