TIDAL FRONT AT OSAKA BAY, JAPAN, IN WINTER

The detailed structure of an oceanic front at Osaka Bay, Japan was obs erved in January 1992. The front separates the stratified nearshore re gion from the well-mixed region of the central part of the bay. The fr ont runs in the domain where the value of log(h/U-3) (where h is the w ater depth in meters and U the amplitude of the M(2) tidal current in m s(-1)) ranges from 3.0 to 3.5, showing that tidal stirring plays an important role in its formation. We may consider this front as a tidal front in winter, because the large fresh water inflow generates the d ensity stratification in spite of the strong sea surface cooling. The difference of positions of the tidal front at Osaka Bay between winter and summer is also discussed.