Fig. 4From: 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 variations of AM2, AM2', ERM2, AS1, AS2, AS3, and TEC0 (a to g) calculated with Eq. (1) from TEC data in Fig. 3. The vertical dashed lines are the same as those in Fig. 2a. The horizontal dashed lines represent the geomagnetic equatorBack to article page