An unusual reduction in the mesospheric semi-diurnal tidal amplitude over Tirunelveli (8.7°N, 77.8°E) prior to the 2011 minor warming and its relationship with stratospheric ozone

There is an unusual decrease of semi-diurnal tidal amplitude in zonal wind at 88 km over Tirunelveli (8.7°N, 77.8°E) prior to the onset of a minor warming event of 2011. During that time, there is a sudden decrease of TIMED-SABER observed ozone volume mixing ratio (VMR) at equator and 60°N. It is suggested that the enhanced planetary wave activity prior to the occurrence of SSW increases the strength of the Brewer–Dobson circulation, which transports stratospheric ozone, the solar insolation absorption of which mainly generates semi-diurnal tide, to high-latitude lower stratosphere and as expected, ozone VMR at 70°N increases in the lower stratosphere.

► Prior to minor SSW 2011, unusual decrease of low-latitude mesospheric 12 h tide. ► Upper stratospheric ozone VMR decreases drastically at equator and at 60°N. ► Lower stratospheric ozone VMR increases at 70°N due to poleward ozone transport. ► The strengthened Brewer–Dobson circulation causes ozone transport to polar stratosphere.