ORIGINAL ARTICLE Statistics of GPS ionospheric scintillation and irregularities over polar regions at solar minimum

Abstract A statistical study of the occurrence charac-teristic of GPS ionospheric scintillation and irregularity in the polar latitude is presented. These measurements were made at Ny-Alesund, Svalbard [78.9N, 11.9E; 75.8N corrected geomagnetic latitude (CGMLat)] and Larsemann Hills, East Antarctica (69.4S, 76.4E; 74.6S CGMLat) during 2007–2008. It is found that the GPS phase scintil-lation and irregularity activity mainly takes place in the months 10, 11 and 12 at Ny-Alesund, and in the months 5, 6 at Larsemann Hills. The seasonal pattern of phase scin-tillation with respect to the station indicates that the GPS phase scintillation occurrence is a local winter phenome-non, which shows consistent results with past studies of 250 MHz satellite beacon measurements. The occurrence rates of GPS amplitude scintillation at the two stations are below 1%. A comparison with the interplanetary magnetic field (IMF) By and Bz components shows that the phase scintillation occurrence level is higher during the period from later afternoon to sunset (16–19 h) at Ny-Alesund, and from sunset to pre-midnight (18–23 h) at Larsemann Hills for negative IMF components. The findings seem to indicate that the dependence of scintillation and irregularity occurrence on geomagnetic activity appears to be associ-ated with the magnetic local time (MLT)