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 the strongest below the main thermocline (150&#8722 200 m) where the observed 5oC isotherm displacement is more than 50 m. The Richardson numbers show low values (0&#8722 0.25) in layers where large vertical displacements occur, suggesting that internal tides could be a major process for ocean mixing around the observation site. Numerical simulations using an idealized vertical 2.5-dimensional numerical model based on the ROMS reveal that semi-diurnal internal tides are dominantly generated close to the observation site. Simulations using different configurations are also conducted for further understanding of internal tide generation mechanism and its impact on ocean mixing in this region.