Generation mechanism of near-inertial internal waves observed off the East Coast of Korea

Abstract

Near-inertial internal waves of frequency 0.0535 cph with upward or downward phase propagations were observed off the east coast of Korea where the local inertial frequency is 0.0510 cph. Using a linear model in which the motion in the mixed layer is driven by the local wind stress as in earlier studies, we have investigated generation mechanism of the observed waves. The model reproduces waves with upward phase velocity well and shows that the waves were driven by the local wind stress. The model, however, cannot reproduce the waves with downward phase velocity, because the model requires an energy source at the surface while the waves require an energy source at the bottom. The waves, instead, were due to bottom reflection of waves propagating from the south along the isobaths.