Fig. 1From: Latitudinal and interhemispheric differences of the ionospheric semi-diurnal lunitidal perturbations during the 2009 Arctic sudden stratospheric warming event in the eastern Asia–Australia sectorThe locations of the used ground-based observation stations. The curved dashed and solid lines represent the geomagnetic latitudes. The GNSS, ionosonde, and magnetometer stations are illustrated with red, black, and blue triangles, respectivelyBack to article page