Large-scale traveling ionospheric disturbances observed using GPS receivers over high-latitude and equatorial regions

This paper presents the first results of large-scale traveling ionospheric disturbances (LSTIDs) observation during two moderate magnetic storm events on 28 May 2011 (SYM-H∼ −94 nT and Dst∼−80 nT) and 6 August 2011 (SYM-H∼−126 nT and Dst∼−113 nT) over the high-latitude region in Russia, Sweden, Norway, Iceland and Greenland and equatorial region in the Peninsular Malaysia using vertical total electron content (VTEC) from the Global Positioning System (GPS) observations measurement. The propagation of the LSTID signatures in the GPS TEC measurements over Peninsular Malaysia was also investigated using VTEC map. The LSTIDs were found to propagate both equatorward and poleward directions during these two events. The results showed that the LSTIDs propagated faster at high-latitude region with an average phase velocity of 1074.91 m/s than Peninsular Malaysia with an average phase velocity of 604.84 m/s. The LSTIDs at the high-latitude region have average periods of 150 min whereas the ones observed over Peninsular Malaysia have average periods of 115 min. The occurrences of these LSTIDs were also found to be the subsequent effects of substorm activities in the auroral region. To our knowledge, this is the first result of observation of LSTIDs over Peninsular Malaysia during the 24th solar cycle.