Global distribution, seasonal, and inter-annual variations of mesospheric semidiurnal tide observed by TIMED TIDI

► The SW1 peaks near the South Pole in December and near the North Pole in March. ► SW1 is stronger in the southern hemisphere. ► The two-year variations in the March northern SW1 zonal amplitude may be QBO related. ► Increases in the mid-latitude SW2 during SSW events were observed but not always consistent. ► SW2 increases may be related to an increase of ozone at mid and high latitudes during SSWs.