Scattering of Coastal-Trapped Waves by Irregularities in Coastline and Topography

Abstract

The scattering of freely-propapting coastal-trapped waves (CTWs) by large variations in coastline and topography is studied using a numerical model which accomodates arbitrary density stratification, bathymetry and coastline. Particular attention is paid to the role of stratification which in moderate amounts can eliminate backscattered free-waves which occur. theoretically, in a barotropic ocean. Numerical simulations using widening and narrowing shelf topographies show that the strength of the forward scattering into transmitted CTW modes is proportional to a topographic warp factor which estimates the severity of the topographic irregularities. The forward-scattering is further amplified by density stratification. Within the scattering region itself, the strengths of the scattered-wave-induced currents exhibit substantial variation over short spatial scales. There is generally a marked intensification of the flow within the scattering region, and rapid variations in phase. On narrowing shelves... Abstract The scattering of freely-propapting coastal-trapped waves (CTWs) by large variations in coastline and topography is studied using a numerical model which accomodates arbitrary density stratification, bathymetry and coastline. Particular attention is paid to the role of stratification which in moderate amounts can eliminate backscattered free-waves which occur. theoretically, in a barotropic ocean. Numerical simulations using widening and narrowing shelf topographies show that the strength of the forward scattering into transmitted CTW modes is proportional to a topographic warp factor which estimates the severity of the topographic irregularities. The forward-scattering is further amplified by density stratification. Within the scattering region itself, the strengths of the scattered-wave-induced currents exhibit substantial variation over short spatial scales. There is generally a marked intensification of the flow within the scattering region, and rapid variations in phase. On narrowing shelves...