Typhoon-induced, highly nonlinear internal solitary waves off the east coast of Korea

Abstract

Highly nonlinear internal solitary waves (ISWs) propagating both onshore and offshore were detected in a SAR image taken approximately 19 hours after typhoon MAEMI's passage across the east coast of Korea. Analysis of ocean buoy data suggests that the ISWs were generated by near-inertial waves in response to typhoon wind. The near-inertial waves can propagate seaward due to a downwelling coastal jet (positive relative vorticity offshore of the jet), and interact with sharply varying topography, producing the ISWs. The area of sharply varying topography approximately 28 km off the coast is suggested as a source region for the ISWs. Simple calculations of wave speed based on the two-layered Korteweg-de Vries (KdV) equation with upper layer thickness and densities at both layers fixed indicate that the ISWs were generated 6 hours prior to the time of the acquisition of the SAR image (approximately 13 hours after the typhoon passage), consistent with simultaneous buoy measurements. Copyright 2007 by the American Geophysical Union.