2001, Merzlyakov, E.G., Portnyagin, Yu.I., Jacobi, C., Mitchell, N.J., Muller, H.G., Manson, A.H., Fachrutdinova, A.N., Singer, W., Hoffmann, P.

The longitudinal structure of the day-to-day variations of semidiurnal tide amplitudes is analysed based on coordinated mesosphere/lower thermosphere wind measurements at several stations during three winter campaigns. Possible excitation sources of these variations are discussed. Special attention is given to a nonlinear interaction between the semidiurnal tide and the day-to-day mean wind variations. Data processing includes the S-transform analysis which takes into account transient behaviour of secondary waves. It is shown that strong tidal modulations appear during a stratospheric warming and may be caused by aperiodic mean wind variations during this event.