AMPLIFICATION OF TIDAL CURRENTS BY OVERFLOW ON THE ICELAND-FAEROE RIDGE

During several days in July 1990, there was an abrupt increase in semidiurnal tidal current in the upper part of the water column seaward of the steep continental rise southeast of Iceland. This tidal burst was coincident with an alongslope current pulse formed by water from the Nordic seas, which had overflowed the Iceland-Faeroe Ridge, The tidal increase is shown to be caused by enhanced generation of internal tide when the alongshore current elevated otherwise deep isopycnals to higher levels, thereby increasing conversion from barotropic to baroclinic tides. A two-dimensional model, used to illustrate the mechanism, underpredicts the increased tidal amplitude and suggests that three-dimensional effects play a role in the present case.