The ionospheric convection pattern and locations of selected GPS satellites which were tracked at Ny-Ålesund (NYA) and Longyearbyen (LYB) stations in the prenoon (a) and postnoon (b) convection cells. The data are projected onto a geomagnetic coordinate grid. The GPS satellites are projected onto the map by assuming an ionospheric pierce point (IPP) altitude of 350 km.The start and end time of each track are indicated by “HH:MM” in UT near the start and end of each track. The GPS IPPs are shown using different symbols and colors: black crosses indicate σ _ϕ < 0.1 rad, cyan dots indicate σ _ϕ between 0.1and 0.5 rad whose sizes are according to the GPS phase scintillation level, and red triangles indicate σ _ϕ > 0.5 rad. The tracks of different GPS satellites are annotated by the receiving station and their PRN (pseudorandom noise) code. For example N5 indicates PRN5 tracked at NYA station, while L5 indicates PRN5 tracked at LYB station. The locations of NYA and LYB are shown by black dots which are annotated in panel a.