Evidence for SSW triggered Q6DW-tide and Q6DW-gravity wave interactions observed by meteor radars at 30°S

An exceptionally strong westward propagating quasi-6-day wave (Q6DW) with zonal wavenumber 1 in connection with the rare 2019 Southern Hemispheric Sudden Stratospheric Warming (SSW) is observed by two meteor radars at 30 degrees S and is found to modulate and interact with the diurnal tide and gravity waves (GWs). The diurnal tide is amplified every 6 days and a prominent 21 hr child wave attributed to Q6DW-diurnal tide nonlinear interaction occurs. Q6DW modulation on GWs is confirmed as the 4-5 day periodicity in GW variances. Simultaneously, the Q6DW appears to shift its period toward the periodicity of the modulated GW variances. Enhancement is also observed in the first results of meteor radar observed Q6DW Eliassen-Palm flux, which may facilitate the global perturbation and persistence of this Q6DW. We conclude that the observed SSW triggered Q6DW-tide and Q6DW-GW interactions play an important role in coupling the lower atmospheric forcings to ionospheric variabilities.