High-order solar migrating tides quench at SSW onsets | CU Experts

Sudden stratospheric warming events (SSWs) are the most spectacular; atmospheric vertical coupling processes, well-known for being associated; with diverse wave activities in the upper atmosphere and ionosphere. The; first four solar tidal harmonics have been reported as being engaged.; Here, combining mesospheric winds detected by three mid-latitude radars,; we demonstrate at least the first six harmonics occur during SSW 2018.; Wavenumber diagnosis demonstrates that all six harmonics are dominated; by migrating components. Wavelet analyses reveal that the 4th, 5th, and; 6th harmonics quench after the SSW onset. The six harmonics and the; quenching appear also in a statistical analysis based on near-12-year; observations from one of the radars. We attribute the quenching to; reversal of the background eastward wind.

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