Tidally generated internal wave packets in Massachusetts Bay

Observations in Massachusetts Bay of high-frequency internal wave packets indicate that they are caused by lee waves generated outside a submarine bank at the bay's seaward margin during ebb tide. The lee waves propagate into the bay as the tide turns to flood, steepen nonlinearly, and develop into the packet. A 200-kHz acoustic back-scattering system detected the evolution of the packets. Large overturning events were observed acoustically and in density profiles. Plankton distributions undergo strong vertical displacements and mixing associated with the wave packet passage.