Southern Hemisphere (SH) Midlatitude MLT response to the 2019 SH SSW, revealed by two meteor radar observations and SD-WACCM-X simulations

An exceptionally strong quasi-6-day wave (Q6DW) activity broadly observed in the mesosphere, thermosphere, and ionosphere (MTI) is believed to be associated with the rare September 2019 SH minor SSW and coupled the whole atmosphere. In this study we present evidence of its modulation with the amplified diurnal tides and gravity waves (GW) at SH midlatitudes, using two meteor radar observations and a recently developed 3DVAR algorithm. This algorithm creates a tomographic reconstruction of the 3D wind field based on optimal estimation technique and Bayesian statistics as well as GW variances. It is particularly suitable for investigating GW dynamics on regional scales. We further present the first results of meteor radar observed Q6DW E-P flux and its comparison with SD-WACCM-X simulated Q6DW E-P flux. The results demonstrated that this SSW-related Q6DW activity had a significant impact on the dynamically coupled MTI system at SH midlatitudes. This work also demonstrated the capability of the multi-static CONDOR meteor radar system (centered at 31.2˚S,70.0˚W) in resolving oscillations of small spatial scales over a broad range of periods, and for calculating E-P flux of planetary waves.