Observation and simulation of internal tides on the continental slope of the southwestern East Sea

Abstract

Internal tides near the continental slope of the southwestern East Sea are investigated using two sets of 25-hour-long hourly CTD and LADCP profiles obtained during spring and neap tidal periods. The profiles span the whole water column from the surface to about 260 m. Semi-diurnal internal tide is strongest below the main thermocline (150&#8722 200 m) where the isotherm displacement is more than 50 m. The low Richardson numbers (0-0.25) found below the thermocline imply that internal tidal waves with large vertical displacement of the water column could be one of the major turbulent mixing energy sources in this continental slope region. Numerical simulations using an idealized vertical 2.5-dimensional numerical model using the ROMS reveal that semi-diurnal internal tides are generated near the observation site. from the surface to about 260 m. Semi-diurnal internal tide is strongest below the main thermocline (150&#8722 200 m) where the isotherm displacement is more than 50 m. The low Richardson numbers (0-0.25) found below the thermocline imply that internal tidal waves with large vertical displacement of the water column could be one of the major turbulent mixing energy sources in this continental slope region. Numerical simulations using an idealized vertical 2.5-dimensional numerical model using the ROMS reveal that semi-diurnal internal tides are generated near the observation site.