MF RADAR OBSERVATIONS OF TIDES AND THEIR INTERACTIONS OVER WUHAN （30°N, 114°E）

Data obtained from the medium-frequency （MF） radar at Wuhan （30°N, 114°E） from 11 to 25 February and from 28 February to 13 March have been used to study the tidal oscillations and their interactions at mesopause （80-98km） region over Wuhan in winter. A dynamic spectral variation of disturbance amplitude illustrates a prominent peak at a period of 24 hours at all heights and almost uninterrupted, and there are occasionally slightly strong semidiurnal and weak terdiurnal tidal disturbances. These indicate that in the mid-latitude regions, the diurnal tide is the dominant tidal disturbance at mesopause in winter. A detailed analysis of tidal amplitudes and their wave kinematical energies implies that there may be significant resonant interaction among the diurnal, semidiurnal and terdiurnal tides. The phase profiles of the diurnal tides show obvious increase trend with the increasing heights in both the zonal and meridional directions, which indicate that the observed diurnal tides are propagating upward. The mean vertical wavelengths of the diurnal tides obtained from the zonal and meridional phases are 45km and 47km, respectively, and the corresponding downward phase velocities are 1.88km/h and 1.97km/h, respectively.