Internal Waves in the northern East China Sea

Abstract

The bottom mounted ADCP data obtained in the area southwest of Jeju-do in the northern East China Sea in the summer of 2005 and 2006 are used to study internal waves. The observed internal waves generally influenced the whole water column. Manifestation of large-amplitude internal waves was mostly observed during the low tidal phase in 2005, but during a transition phase from high to low tide in 2006. During several internal wave episodes, large-amplitude solitary wave-like features emerged preceding higher frequency internal waves. Shear instability of tidal currents is explored as a possible mechanism for sustaining or regenerating internal waves. The spectral densities of the horizontal velocities approximately followed f^-1 in the frequency subrange between f_0~cpmin and the buoyancy frequency, where f_0 is a transition point between the f^-1 subrange and the steep falloff of energy from the tidal peak at f_M2 towards higher frequencies.