Signature of Sudden Stratospheric Warming in the Pole and Its Antipode

In this study, the boreal sudden stratospheric warming (SSW) event of 2013 and the austral SSW event of 2019 are considered to investigate the influence of the SSW events on the polar and antipodal upper mesosphere and lower thermosphere (UMLT) regions using ground-based, space-borne, reanalysis and model data sets. During the SSW events, the solar semi-diurnal tidal (SDT) amplitudes are much larger than the lunar amplitudes in both UMLT regions. Besides, the solar SDT shows an increase in its amplitude in both the polar UMLT heights during the SSW events. However, the lunar tides show enhancement in its amplitude in the boreal polar UMLT region during both the SSW events. In the antipodal UMLT region, a peak enhancement in solar SDT amplitude is observed a few days after the onset of the boreal SSW and near to the onset time of the austral SSW. No concurrent stratospheric ozone volume mixing ratio (vmr) increase is observed which indicates that the SDT peak can be unlikely due to the underlying stratospheric ozone vmr changes. However, similar periodicity in the UMLT zonal winds of both poles indicates the possibility of cross equatorial propagation of planetary wave (PW). As the SDT amplitude also reveal similar planetary wave periodicity as observed in zonal wind, it is suggested that the PW modulation of the SDT could be the reason for the enhancement of SDT in the opposite polar UMLT region. This work provides an observational evidence of the cross equatorial propagation of PWs associated with the SSW events that affect the UMLT region extending up to the next pole. Using ground-based, space-borne, reanalysis and model outputs, the tidal and PW activity during two SSWs (2013 and 2019) are studied simultaneously over both the poles. The meteor radar observation reveals the dominance of solar SDT in the polar UMLT region compared to the lunar tides and its amplitude increases around the SSW onset days. A peak in the antipodal SDT is observed in the UMLT region with no simultaneous increase in the stratospheric ozone. It is suggested that a cross equatorial propagation of PW periodicity associated with the SSW events may modulate the solar SDT in the antipodal UMLT region and result in its increased amplitude after the SSW events. Solar semi-diurnal tide enhances in both polar mesosphere during sudden stratospheric warming but at no relation with stratospheric ozone Solar tides are relatively stronger than lunar tides with the enhancement of the latter observed only in the boreal polar mesosphere Similar planetary waves in both polar mesosphere and their modulation of solar tides in antipode show their cross equatorial propagation