Abstract:
This study delved into atmospheric tides and their dynamics during two major boreal sudden stratospheric warmings (SSWs). Using meteor radar wind data, our investigation unveiled compelling indications of non-linear interactions between the semidiurnal solar tide and the quasi-20-day wave (Q20dw) in the high latitude mesosphere and lower thermosphere (MLT) during SSWs. Additionally, the diagnosis of zonal wavenumbers indicated potential non-linear interaction between the dominant semidiurnal migrating tide (SW2) and the zonally symmetric 20-day wave (20dw0) component, generating secondary waves. The study emphasized the significance of the non-linear interaction between the zonal wavenumber 2 component of the stationary planetary wave (SPW2) and the westward propagating 20-day wave (20dwW2) in the stratosphere, crucial in producing the 20dw0. The meteor radar wind spectra suggested that the excited 20dw0 possibly engages in non-linear interactions with SW2, further generating secondary waves in the MLT. Therefore, this study presents the observational evidence of a two-step non-linear interaction associated with zonally symmetric planetary waves during major SSWs.