Variations of the Quasi 6‐Day and 16‐Day Waves From the Troposphere to the Lower Thermosphere During the 2018/2019 Major SSW

Abstract Combining meteor radar observations at Mohe (MH; 53.5°N, 122.5°E), Wuhan (WH; 30.5°N, 114.4°E), and Ledong (LD; 18.5°N, 108.8°E) stations and reanalysis data, we studied planetary wave (PW) activities from the troposphere to the mesosphere and lower thermosphere (MLT) during the major 2018/2019 sudden stratospheric warming (SSW). The quasi 4‐day wave (Q4DW), quasi 6‐day wave (Q6DW), and quasi 16‐day wave (Q16DW) were all enhanced; however, the Q4DW is the smallest increase in zonal and meridional wind amplitude. The maximum amplitudes of the Q16DW and Q6DW reached about 34.3 m/s at 55.4 km and 23.3 m/s at 53.6 km at MH, respectively. Overall, significant Q16DW and Q6DW were observed in the high‐latitude stratosphere and MLT region. However, at LD, they were only evident in the MLT region. In general, the amplitude peaks decreased sequentially from the MH to WH and LD stations. More interestingly, the peak amplitudes at lower latitudes occurred behind those at higher latitudes, suggesting that these planetary waves propagated equatorward and upward. This suggests that during the SSW, strong PW activity affects not only the vertical coupling but also the dynamics at the low latitudes in the MLT region, resulting in atmospheric coupling across different latitudes. The E‐P flux and zonal wave drag analyses confirmed that numerous planetary waves propagated upward and equatorward above ∼30 km. The stationary planetary wave (SPW) exerted significantly stronger drag than the Q16DW and Q6DW, indicating that SPW played a crucial role in the reversal of the zonal wind and the formation of the 2018/2019 SSW.