Fig. 2From: Impact of strong and weak stratospheric polar vortices on geomagnetic semidiurnal solar and lunar tidesScatter plot between the anomalies in S2 and L2 geomagnetic tides versus the Northern Annular Mode (NAM) at 10Â hPa. Results are restricted to the period of 15 December to 1 March for all the available data between 1980 and 2020. The S2 and L2 tidal anomalies are plotted against NAM with a lag of 10 and 0Â days, respectivelyBack to article page